Intriguing Morphology Evolution from Noncrosslinked Poly(tert-butyl acrylate) Seeds with Polar Functional Groups in Soap-Free Emulsion Polymerization of Styrene.

PubMed

Wang, Lu; Pan, Mingwang; Song, Shaofeng; Zhu, Lei; Yuan, Jinfeng; Liu, Gang

2016-08-09

Herein, we demonstrate a facile approach to prepare anisotropic poly(tert-butyl acrylate)/polystyrene (PtBA/PS) composite particles with controllable morphologies by soap-free seeded emulsion polymerization (SSEP). In the first step, noncrosslinked PtBA seeds with self-stabilizing polar functional groups (e.g., ester groups and radicals) are synthesized by soap-free emulsion polymerization. During the subsequent SSEP of styrene (St), PS bulges are nucleated on the PtBA seeds due to the microphase separation confined in the latex particles. The morphology evolution of PtBA/PS composite particles is tailored by varying the monomer/seed feed ratio, polymerization time, and polymerization temperature. Many intriguing morphologies, including hamburger-like, litchi-like, mushroom-like, strawberry-like, bowl-like, and snowman-like, have been acquired for PtBA/PS composite particles. The polar groups on the PtBA seed surface greatly influence the formation and further merging of PS/St bulges during the polymerization. A possible formation mechanism is proposed on the basis of experimental results. These complex composite particles are promising for applications in superhydrophobic coatings.

A novel headspace gas chromatographic method for in situ monitoring of monomer conversion during polymerization in an emulsion environment.

PubMed

Chai, Xin-Sheng; Zhong, Jin-Feng; Hu, Hui-Chao

2012-05-18

This paper describes a novel multiple-headspace extraction/gas chromatographic (MHE-GC) technique for monitoring monomer conversion during a polymerization reaction in a water-based emulsion environment. The polymerization reaction of methyl methacrylate (MMA) in an aqueous emulsion is used as an example. The reaction was performed in a closed headspace sample vial (as a mini-reactor), with pentane as a tracer. In situ monitoring of the vapor concentration of the tracer, employing a multiple headspace extraction (sampling) scheme, coupled to a GC, makes it possible to quantitatively follow the conversion of MMA during the early stages of polymerization. Data on the integrated amount of the tracer vapor released from the monomer droplet phase during the polymerization is described by a mathematic equation from which the monomer conversion can be calculated. The present method is simple, automated and economical, and provides an efficient tool in the investigation of the reaction kinetics and effects of the reaction conditions on the early stage of polymerization. Copyright © 2012 Elsevier B.V. All rights reserved.

Synthesis of dodecylamine-functionalized graphene quantum dots and their application as stabilizers in an emulsion polymerization of styrene.

PubMed

Xuan, Wang; Ruiyi, Li; Zaijun, Li; Junkang, Liu

2017-11-01

Pickering emulsions have attracted considerable interest due to their potential applications in many fields, such as the food, pharmaceutical, petroleum and cosmetics industries. The study reports the synthesis of dodecylamine-functionalized graphene quantum dots (d-GQDs) and their implementation as stabilizers in an emulsion polymerization of styrene. First, d-GQDs are prepared by thermal pyrolysis of citric acid and dodecylamine in 0.1M ammonium hydroxide. The resulting d-GQDs consist of small graphene sheets with abundant amino, carboxyl, acylamino, hydroxyl and alkyl chains on the edge. The amphiphilic structure gives the d-GQDs high surface activity. The addition of d-GQDs can reduce the surface tension of water to 30.8mNm -1 and the interfacial tension of paraffin oil/water to 0.0182mNm -1 . The surface activity is much better than that of previously reported solid particle surfactants for Pickering emulsions and is close to that of sodium dodecylbenzenesulfonate, which is, a classical organic surfactants. Then, d-GQDs are employed as solid particle surfactants for stabilizing styrene-in-water emulsions. The emulsions exhibit excellent stability at pH 7. However, stability is lost when the pH is more than 9 or less than 4. The pH-switchable behaviour can be attributed to the protonation of amino groups in a weak acid medium and dissociation of carboxyl groups in a weak base medium. Finally, 2,2'-azobis(2-methylpropionitrile) is introduced into the Pickering emulsions to trigger emulsion polymerization of styrene. The as-prepared polystyrene spheres display a uniform morphology with a narrow diameter distribution. The fluorescent d-GQDs coated their surfaces. This study presents an approach for the fabrication of amphiphilic GQDs and GQDs-based functional materials, which have a wide range of potential applications in emulsion polymerization, as well as in sensors, catalysts, and energy storage. Copyright © 2017 Elsevier Inc. All rights reserved.

Various aspects of ultrasound assisted emulsion polymerization process.

PubMed

Korkut, Ibrahim; Bayramoglu, Mahmut

2014-07-01

In this paper, the effects of ultrasonic (US) power, pulse ratio, probe area and recipe composition were investigated on two process responses namely, monomer (methyl methacrylate, MMA) conversion and electrical energy consumption per mass of product polymer (PMMA). Pulsed mode US is more suitable than continuous mode US for emulsion polymerization. The probe (tip) area has little effect on the yield of polymerization when comparing 19 and 13 mm probes, 13 mm probe performing slightly better for high conversion levels. Meanwhile, large probe area is beneficial for high conversion efficiency of electric energy to US energy as well as for high radical generation yield per energy consumed. The conversion increased slightly and electrical energy consumption decreased substantially by using a recipe with high SDS and monomer concentrations. Conclusions presented in this paper may be useful for scale-up of US assisted emulsion polymerization. Copyright © 2014 Elsevier B.V. All rights reserved.

Fine-tuning of process conditions to improve product uniformity of polystyrene particles used for wind tunnel velocimetry

NASA Technical Reports Server (NTRS)

Ray, Asit K.

1990-01-01

Monodisperse polymer particles (having uniform diameter) were used for the last two decades in physical, biological, and chemical sciences. In NASA Langley Research Center monodisperse polystyrene particles are used in wind tunnel laser velocimeters. These polystyrene (PS) particles in latex form were formulated at the Engineering Laboratory of FENGD using emulsion-free emulsion polymerization. Monodisperse PS latices particles having different particle diameters were formulated and useful experimental data involving effects of process conditions on particle size were accumulated. However, similar process conditions and chemical recipes for polymerization of styrene monomer have often yielded monodisperse particles having varying diameters. The purpose was to improve the PS latex product uniformity by fine-tuning the process parameters based on the knowledge of suspension and emulsion polymerization.

In situ functionalization and PEO coating of iron oxide nanocrystals using seeded emulsion polymerization.

PubMed

Kloust, Hauke; Schmidtke, Christian; Feld, Artur; Schotten, Theo; Eggers, Robin; Fittschen, Ursula E A; Schulz, Florian; Pöselt, Elmar; Ostermann, Johannes; Bastús, Neus G; Weller, Horst

2013-04-16

Herein we demonstrate that seeded emulsion polymerization is a powerful tool to produce multiply functionalized PEO coated iron oxide nanocrystals. Advantageously, by simple addition of functional surfactants, functional monomers, or functional polymerizable linkers-solely or in combinations thereof-during the seeded emulsion polymerization process, a broad range of in situ functionalized polymer-coated iron oxide nanocrystals were obtained. This was demonstrated by purposeful modulation of the zeta potential of encapsulated iron oxide nanocrystals and conjugation of a dyestuff. Successful functionalization was unequivocally proven by TXRF. Furthermore, the spatial position of the functional groups can be controlled by choosing the appropriate spacers. In conclusion, this methodology is highly amenable for combinatorial strategies and will spur rapid expedited synthesis and purposeful optimization of a broad scope of nanocrystals.

Synthesis of amphipathic block copolymers based on polyisobutylene and polyoxyethylene and their application in emulsion polymerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sar, B.

1992-12-31

Polymer colloids stabilized by polymeric surfactants are of great interest both commercially and academically. It has been found that these materials enhance latex stabilization in a number of applications. The polymeric surfactants are amphipathic block and graft copolymers containing both hydrophilic and hydrophobic moieties. The current study involved the synthesis of a series of amphipathic triblock copolymers, polyisobutylene-block-polyoxyethylene-block-polyisobutylene (PIB-b-POE-b-PIB), for use in the emulsion polymerization of styrene (STY), methyl methacrylate (MMA), and vinyl acetate (VAc). The stabilizing effectiveness of these triblock copolymers was studied as a function of their blocklength. When the molecular weight of the POE center block wasmore » changed from M{sub n} = 2,000 to 20,000 g/mole, stable lattices were obtained in emulsion polymerization with MMA, STY, and VAc as the monomers. In all cases, the polymerization rates remained constant, while the number of particles/volume decreased with increasing POE chain length. When the molecular weight of the PIB end blocks was changed from M{sub n} = 400 to 2,600 g/mole keeping the molecular weight of the POE center block constant at M{sub n} = 20,000 g/mole, the poly(methyl methacrylate) and poly(vinyl acetate) lattices exhibited similar behavior, i.e., the number of particles and particle sizes remained the same, but the rate of polymerization reached a maximum at 87 wt% POE content. In the case of poly(styrene) both the rate of polymerization and the number of particles remained constant. The emulsion polymerization of other monomers such as butadiene, acrylonitrile, methyl acrylate, ethyl acrylate, and butyl acrylate was carried out by using one triblock copolymer, i.e., PIB(400)-b-POE (8,000)-b-PIB-(400). Stable lattices were also formed in all cases.« less

21 CFR 175.210 - Acrylate ester copolymer coating.

Code of Federal Regulations, 2014 CFR

2014-04-01

... polymerized copolymer of ethyl acrylate, methyl methacrylate, and methacrylic acid applied in emulsion form to... of the polymer and in the preparation and application of the emulsion may include substances named in... amount required as a preservative in emulsion defoamer. Disodium hydrogen phosphate Do. Formaldehyde...

Synthesis and characterization of functional acrylic copolymers via RAFT mini-emulsion polymerization

NASA Astrophysics Data System (ADS)

Yılmaz, Onur; Özkan, ćiǧdem Kılıçarislan; Yılmaz, Catalina N.; Yorgancıoǧlu, Ali; Özgünay, Hasan; Karavana, Hüseyin Ata

2017-12-01

Copolymers bearing reactive functional groups with controlled molecular weights are of importance since they can be used in many fields such as composites, coatings, membranes, catalysis, biology, optoelectronics, pharmaceuticals, etc. In the present study low molecular weight copolymers based on butyl acrylate (BA) and methyl methacrylate (MMA) in combination with reactive functional monomers of vinyl trietoxysilane (VTES), 3-trimetoxysilylpropyl methacrylate (TMSPMA) and glycidyl methacrylate (GMA) were synthesized via RAFT mini-emulsion technique using 2-cyano 2-propyldodecyldithiocarbonate as CTA agent. The results showed that the average molecular weights of copolymers were close to the theoretical values. On the other hand, PDI values were found to be higher than conventional RAFT polymers. The particle sizes of the latexes were small with very homogenous distributions and good stability. FTIR, H-NMR and TGA results verified the success of copolymer syntheses.

Production methodologies of polymeric and hydrogel particles for drug delivery applications.

PubMed

Lima, Ana Catarina; Sher, Praveen; Mano, João F

2012-02-01

Polymeric particles are ideal vehicles for controlled delivery applications due to their ability to encapsulate a variety of substances, namely low- and high-molecular mass therapeutics, antigens or DNA. Micro and nano scale spherical materials have been developed as carriers for therapies, using appropriated methodologies, in order to achieve a prolonged and controlled drug administration. This paper reviews the methodologies used for the production of polymeric micro/nanoparticles. Emulsions, phase separation, spray drying, ionic gelation, polyelectrolyte complexation and supercritical fluids precipitation are all widely used processes for polymeric micro/nanoencapsulation. This paper also discusses the recent developments and patents reported in this field. Other less conventional methodologies are also described, such as the use of superhydrophobic substrates to produce hydrogel and polymeric particulate biomaterials. Polymeric drug delivery systems have gained increased importance due to the need for improving the efficiency and versatility of existing therapies. This allows the development of innovative concepts that could create more efficient systems, which in turn may address many healthcare needs worldwide. The existing methods to produce polymeric release systems have some critical drawbacks, which compromise the efficiency of these techniques. Improvements and development of new methodologies could be achieved by using multidisciplinary approaches and tools taken from other subjects, including nanotechnologies, biomimetics, tissue engineering, polymer science or microfluidics.

Preparation of polystyrene/SiO2 microsphere via Pickering emulsion polymerization: Synergistic effect of SiO2 concentrations and initiator sorts

NASA Astrophysics Data System (ADS)

Zhou, Haiou; Shi, Tiejun; Zhou, Xun

2013-02-01

In this paper, polystyrene (PS)/SiO2 microspheres were successfully prepared via Pickering emulsion polymerization stabilized solely by ethacryloxypropyltrimethoxysilane (MPTMS) modified SiO2 nanoparticles. The formation mechanisms of PS/SiO2 microspheres with different morphology were investigated under various Pickering emulsion polymerization conditions. The results showed that SiO2 concentrations and initiator sorts would synergistically impact on the morphology of products corresponding to distinct formation mechanisms. When SiO2 concentrations was low and water-solute initiator potassium persulfate (KPS) was used, aqueous nucleation was dominant, which was deduced to the formation of dispersive microspheres sparsely anchored by SiO2 particles. When SiO2 concentrations was increased and oil-solute initiator azobisisobutyronitrile (AIBN) was applied, nucleation in oil phase prevailed which lead to the formation of microspheres densely packed by SiO2 particles.

SOURCE ASSESSMENT: POLYVINYL CHLORIDE

EPA Science Inventory

This report summarizes data on air emissions from the polyvinyl chloride (PVC) industry. PVC is manufactured by 20 companies at 35 plants. Each plant uses one or more of four possible polymerization processes: (1) suspension polymerization, (2) emulsion polymerization, (3) bulk p...

Bio-Functional, Lanthanide-Labeled Polymer Particles by Seeded Emulsion Polymerization and their Characterization by Novel ICP-MS Detection.

PubMed

Thickett, Stuart C; Abdelrahman, Ahmed I; Ornatsky, Olga; Bandura, Dmitry; Baranov, Vladimir; Winnik, Mitchell A

2010-01-01

We present the synthesis and characterization of monodisperse, sub-micron poly(styrene) (PS) particles loaded with up to and including 10(7) lanthanide (Ln) ions per particle. These particles have been synthesized by seeded emulsion polymerization with a mixture of monomer and a pre-formed Ln complex, and analyzed on a particle-by-particle basis by a unique inductively coupled plasma mass cytometer. Seed particles were prepared by surfactant-free emulsion polymerization (SFEP) to obtain large particle sizes in aqueous media. Extensive surface acid functionality was introduced using the acid-functional initiator ACVA, either during seed latex synthesis or in the second stage of polymerization. The loading of particles with three different Ln ions (Eu, Tb, and Ho) has proven to be close to 100 % efficient on an individual and combined basis. Covalent attachment of metal-tagged peptides and proteins such as Neutravidin to the particle surface was shown to be successful and the number of bound species can be readily determined. We believe these particles can serve as precursors for multiplexed, bead-based bio-assays utilizing mass cytometric detection.

Bio-Functional, Lanthanide-Labeled Polymer Particles by Seeded Emulsion Polymerization and their Characterization by Novel ICP-MS Detection

PubMed Central

Thickett, Stuart C.; Abdelrahman, Ahmed I.; Ornatsky, Olga; Bandura, Dmitry; Baranov, Vladimir; Winnik, Mitchell A.

2010-01-01

We present the synthesis and characterization of monodisperse, sub-micron poly(styrene) (PS) particles loaded with up to and including 107 lanthanide (Ln) ions per particle. These particles have been synthesized by seeded emulsion polymerization with a mixture of monomer and a pre-formed Ln complex, and analyzed on a particle-by-particle basis by a unique inductively coupled plasma mass cytometer. Seed particles were prepared by surfactant-free emulsion polymerization (SFEP) to obtain large particle sizes in aqueous media. Extensive surface acid functionality was introduced using the acid-functional initiator ACVA, either during seed latex synthesis or in the second stage of polymerization. The loading of particles with three different Ln ions (Eu, Tb, and Ho) has proven to be close to 100 % efficient on an individual and combined basis. Covalent attachment of metal-tagged peptides and proteins such as Neutravidin to the particle surface was shown to be successful and the number of bound species can be readily determined. We believe these particles can serve as precursors for multiplexed, bead-based bio-assays utilizing mass cytometric detection. PMID:20396648

Self-Assembled Colloidal Particle Clusters from In Situ Pickering-Like Emulsion Polymerization via Single Electron Transfer Mechanism.

PubMed

Yuan, Jinfeng; Zhao, Weiting; Pan, Mingwang; Zhu, Lei

2016-08-01

A simple route is reported to synthesize colloidal particle clusters (CPCs) from self-assembly of in situ poly(vinylidene fluoride)/poly(styrene-co-tert-butyl acrylate) [PVDF/P(St-co-tBA)] Janus particles through one-pot seeded emulsion single electron transfer radical polymerization. In the in situ Pickering-like emulsion polymerization, the tBA/St/PVDF feed ratio and polymerization temperature are important for the formation of well-defined CPCs. When the tBA/St/PVDF feed ratio is 0.75 g/2.5 g/0.5 g and the reaction temperature is 35 °C, relatively uniform raspberry-like CPCs are obtained. The hydrophobicity of the P(St-co-tBA) domains and the affinity of PVDF to the aqueous environment are considered to be the driving force for the self-assembly of the in situ formed PVDF/P(St-co-tBA) Janus particles. The resultant raspberry-like CPCs with PVDF particles protruding outward may be promising for superhydrophobic smart coatings. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Silicone-containing aqueous polymer dispersions with hybrid particle structure.

PubMed

Kozakiewicz, Janusz; Ofat, Izabela; Trzaskowska, Joanna

2015-09-01

In this paper the synthesis, characterization and application of silicone-containing aqueous polymer dispersions (APD) with hybrid particle structure are reviewed based on available literature data. Advantages of synthesis of dispersions with hybrid particle structure over blending of individual dispersions are pointed out. Three main processes leading to silicone-containing hybrid APD are identified and described in detail: (1) emulsion polymerization of organic unsaturated monomers in aqueous dispersions of silicone polymers or copolymers, (2) emulsion copolymerization of unsaturated organic monomers with alkoxysilanes or polysiloxanes with unsaturated functionality and (3) emulsion polymerization of alkoxysilanes (in particular with unsaturated functionality) and/or cyclic siloxanes in organic polymer dispersions. The effect of various factors on the properties of such hybrid APD and films as well as on hybrid particles composition and morphology is presented. It is shown that core-shell morphology where silicones constitute either the core or the shell is predominant in hybrid particles. Main applications of silicone-containing hybrid APD and related hybrid particles are reviewed including (1) coatings which show specific surface properties such as enhanced water repellency or antisoiling or antigraffiti properties due to migration of silicone to the surface, and (2) impact modifiers for thermoplastics and thermosets. Other processes in which silicone-containing particles with hybrid structure can be obtained (miniemulsion polymerization, polymerization in non-aqueous media, hybridization of organic polymer and polysiloxane, emulsion polymerization of silicone monomers in silicone polymer dispersions and physical methods) are also discussed. Prospects for further developments in the area of silicone-containing hybrid APD and related hybrid particles are presented. Copyright © 2015. Published by Elsevier B.V.

Effect of cationic monomer content on polyacrylamide copolymers by frit-inlet asymmetrical flow field-flow fractionation/multi-angle light scattering.

PubMed

Lee, Hyejin; Kim, Jin Yong; Choi, Woonjin; Moon, Myeong Hee

2017-06-23

In this study, ultrahigh-molecular-weight (MW) (>10 7 Da) cationic polyacrylamides (C-PAMs), which are water-soluble polymers used in waste water treatment, were characterized using frit-inlet asymmetrical flow field-flow fractionation coupled with multi-angle light scattering and differential refractive detection. C-PAMs copolymerized with acryloxyethyltrimethyl ammonium chloride (DAC) were prepared by varying the feed amount of cationic monomer, polymerization method (solution vs. emulsion), and degree of branching. The MW of the copolymers prepared using emulsion polymerization (10 7 -10 9 Da) was generally larger than that of copolymers prepared using solution polymerization (4×10 7 -10 8 Da). When the amount of cationic monomer was increased from 10 to 55mol% in solution polymerization, hydrophobic contraction of the core induced formation of more compact C-PAMs. The copolymers prepared using emulsion polymerization formed highly aggregated or supercoil structures owing to increased intermolecular hydrophobic interaction when less cationic monomer was used. However, the MW decreased with increased cationic group content. In addition, C-PAMs larger than ∼10 8 Da prepared using the emulsion method were separated by steric/hyperlayer elution mode while those in the 10 7 -10 8 Da range were analyzed in either normal or steric/hyperlayer mode depending on the decay patterns of field programming. Moreover, branched copolymers were found to be resolved with different elution modes under the same field decay pattern depending on the degree of branching: steric/hyperlayer for low-branching and normal for high-branching C-PAMs. Copyright © 2017 Elsevier B.V. All rights reserved.

A general strategy to synthesize chemically and topologically anisotropic Janus particles

PubMed Central

Fan, Jun-Bing; Song, Yongyang; Liu, Hong; Lu, Zhongyuan; Zhang, Feilong; Liu, Hongliang; Meng, Jingxin; Gu, Lin; Wang, Shutao; Jiang, Lei

2017-01-01

Emulsion polymerization is the most widely used synthetic technique for fabricating polymeric particles. The interfacial tension generated with this technique limits the ability to tune the topology and chemistry of the resultant particles. We demonstrate a general emulsion interfacial polymerization approach that involves introduction of additional anchoring molecules surrounding the microdroplets to synthesize a large variety of Janus particles with controllable topological and chemical anisotropy. This strategy is based on interfacial polymerization mediated by an anchoring effect at the interface of microdroplets. Along the interface of the microdroplets, the diverse topology and surface chemistry features of the Janus particles can be precisely tuned by regulating the monomer type and concentration as well as polymerization time. This method is applicable to a wide variety of monomers, including positively charged, neutrally charged, and negatively charged monomers, thereby enriching the community of Janus particles. PMID:28691089

Galantamine-loaded PLGA nanoparticles, from nano-emulsion templating, as novel advanced drug delivery systems to treat neurodegenerative diseases

NASA Astrophysics Data System (ADS)

Fornaguera, C.; Feiner-Gracia, N.; Calderó, G.; García-Celma, M. J.; Solans, C.

2015-07-01

Polymeric nanoparticles could be promising drug delivery systems to treat neurodegenerative diseases. Among the various methods of nanoparticle preparation, nano-emulsion templating was used in the present study to prepare galantamine-loaded nano-emulsions by a low-energy emulsification method followed by solvent evaporation to obtain galantamine-loaded polymeric nanoparticles. This approach was found to be suitable because biocompatible, biodegradable and safe nanoparticles with appropriate features (hydrodynamic radii around 20 nm, negative surface charge and stability higher than 3 months) for their intravenous administration were obtained. Encapsulation efficiencies higher than 90 wt% were obtained with a sustained drug release profile as compared to that from aqueous and micellar solutions. The enzymatic activity of the drug was maintained at 80% after its encapsulation into nanoparticles that were non-cytotoxic at the required therapeutic concentration. Therefore, novel galantamine-loaded polymeric nanoparticles have been designed for the first time using the nano-emulsification approach and showed the appropriate features to become advanced drug delivery systems to treat neurodegenerative diseases.Polymeric nanoparticles could be promising drug delivery systems to treat neurodegenerative diseases. Among the various methods of nanoparticle preparation, nano-emulsion templating was used in the present study to prepare galantamine-loaded nano-emulsions by a low-energy emulsification method followed by solvent evaporation to obtain galantamine-loaded polymeric nanoparticles. This approach was found to be suitable because biocompatible, biodegradable and safe nanoparticles with appropriate features (hydrodynamic radii around 20 nm, negative surface charge and stability higher than 3 months) for their intravenous administration were obtained. Encapsulation efficiencies higher than 90 wt% were obtained with a sustained drug release profile as compared to that from aqueous and micellar solutions. The enzymatic activity of the drug was maintained at 80% after its encapsulation into nanoparticles that were non-cytotoxic at the required therapeutic concentration. Therefore, novel galantamine-loaded polymeric nanoparticles have been designed for the first time using the nano-emulsification approach and showed the appropriate features to become advanced drug delivery systems to treat neurodegenerative diseases. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03474d

Synthesis and Characterization of Graft Copolymers Poly(isoprene-g-styrene) of High Molecular Weight by a Combination of Anionic Polymerization and Emulsion Polymerization

DOE PAGES

Wang, Wenwen; Wang, Weiyu; Li, Hui; ...

2015-01-14

In this study, high molecular weight “comb-shaped” graft copolymers, poly(isoprene-g-styrene), with polyisoprene as the backbone and polystyrene as side chains, were synthesized via free radical emulsion polymerization by copolymerization of isoprene with a polystyrene macromonomer synthesized using anionic polymerization. A small amount of toluene was used in order to successfully disperse the macromonomer. Both a redox and thermal initiation system were used in the emulsion polymerization, and the latex particle size and distribution were investigated by dynamic light scattering. The structural characteristics of the macromonomer and comb graft copolymers were investigated through use of size exclusion chromatography, spectroscopy, microscopy, thermalmore » analysis, and rheology. While the macromonomer was successfully copolymerized to obtain the desired multigraft copolymers, small amounts of unreacted macromonomer remained in the products, reflecting its reduced reactivity due to steric effects. Nevertheless, the multigraft copolymers obtained were very high in molecular weight (5–12 × 10 5 g/mol) and up to 10 branches per chain, on average, could be incorporated. A material incorporating 29 wt% polystyrene exhibits a disordered microphase separated morphology and elastomeric properties. As a result, these materials show promise as new, highly tunable, and potentially low cost thermoplastic elastomers.« less

Investigation of in vitro Hydrophilic and Hydrophobic Dual Drug Release from Polymeric Films Produced by Sodium alginate-MaterBi® Drying Emulsions.

PubMed

Setti, Chiara; Suarato, Giulia; Perotto, Giovanni; Athanassiou, Athanassia; Bayer, Ilker S

2018-06-18

Emulsions are known to be effective carriers of hydrophobic drugs, and particularly injectable emulsions have been successfully implemented for in vivo controlled drug release. Recently, high internal phase emulsions have also been used to produce porous polymeric templates for pharmaceutical applications. However, emulsions containing dissolved biopolymers both in the oil and water phases are very scarce. In this study, we demonstrate such an emulsion, in which the oil phase contains a hydrophobic biodegradable polymer, MaterBi ® , and the water phase is aqueous sodium alginate dispersion. The two phases were emulsified simply by ultrasonic processing without any surfactants. The emulsions were stable for several days and were dried into composite solid films with varying MaterBi ® /alginate fractions. The films were loaded with two model drugs, a hydrophilic eosin-based cutaneous antiseptic and the hydrophobic curcumin. Drug release capacity of the films was investigated in detail, and controlled release of each model drug was achieved either by tuning the polymer fraction in the films during emulsification or by crosslinking sodium alginate fraction of the films by calcium salt solution immersion. The emulsions can be formulated to carry either a single model drug or both drugs depending on the desired application. Films demonstrate excellent cell biocompatibility against human dermal fibroblast, adult cells. Copyright © 2018. Published by Elsevier B.V.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Habercorn, Lasse; Merkl, Jan-Philip; Kloust, Hauke Christian

With the polymer encapsulation of quantum dots via seeded emulsion polymerization we present a powerful tool for the preparation of fluorescent nanoparticles with an extraordinary stability in aqueous solution. The method of the seeded emulsion polymerization allows a straightforward and simple in situ functionalization of the polymer shell under preserving the optical properties of the quantum dots. These requirements are inevitable for the application of semiconductor nanoparticles as markers for biomedical applications. Polymer encapsulated quantum dots have shown only a marginal loss of quantum yields when they were exposed to copper(II)-ions. Under normal conditions the quantum dots were totally quenchedmore » in presence of copper(II)-ions. Furthermore, a broad range of in situ functionalized polymer-coated quantum dots were obtained by addition of functional monomers or surfactants like fluorescent dye molecules, antibodies or specific DNA aptamers. Furthermore the emulsion polymerization can be used to prepare multifunctional hybrid systems, combining different nanoparticles within one construct without any adverse effect of the properties of the starting materials.{sup 1,2}.« less

Application of mercapto-silica polymerized high internal phase emulsions for the solid-phase extraction and preconcentration of trace lead(II).

PubMed

Su, Rihui; Ruan, Guihua; Chen, Zhengyi; Du, Fuyou; Li, Jianping

2015-12-01

A new class of solid-phase extraction column prepared with grafted mercapto-silica polymerized high internal phase emulsion particles was used for the preconcentration of trace lead. First, mercapto-silica polymerized high internal phase emulsion particles were synthesized by using high internal phase emulsion polymerization and carefully assembled in a polyethylene syringe column. The influences of various parameters including adsorption pH value, adsorption and desorption solvents, flow rate of the adsorption and desorption procedure were optimized, respectively, and the suitable uploading sample volumes, adsorption capacity, and reusability of solid phase extraction column were also investigated. Under the optimum conditions, Pb(2+) could be preconcentrated quantitatively over a wide pH range (2.0-5.0). In the presence of foreign ions, such as Na(+) , K(+) , Ca(2+) , Zn(2+) , Mg(2+) , Cu(2+) , Fe(2+) , Cd(2+) , Cl(-) and NO3 (-) , Pb(2+) could be recovered successfully. The prepared solid-phase extraction column performed with high stability and desirable durability, which allowed more than 100 replicate extractions without measurable changes of performance. The feasibility of the developed method was further validated by the extraction of Pb(2+) in rice samples. At three spiked levels of 40.0, 200 and 800 μg/kg, the average recoveries for Pb(2+) in rice samples ranged from 87.3 to 105.2%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surfactant-free, cationic latices of poly(BMA-co-MMA) using AIBA initiator.

PubMed

Lee, Ki-Chang

2013-09-01

When polymer particles come into use, especially, for photonic crystal applications, their diameter, dispersivity, and refractive indices become very important. Poly(benzyl methacrylate) is known to be a kind of high refracive materials (n = 1.57) compared to poly(methyl methacrylate) (n = 1.49). Not many work was concerned for surfactant-free emulsion polymerization of benzyl methacrylate or its copolymerization using cationic initiators. Narrowly dispersed cationic poly(BMA-co-MMA) and PBMA latices were synthesized successfully by surfactant-free emulsion polymerization with AIBA. The influences of BMA/MMA ratio, BMA/MMA monomer and initiator concentrations, addition of DVB/EGDMA crosslink agent, and polymerization temperature on the kinetics and on the particle size and molecular weight were studied. Monodisperse cationic charged PBMA and poly(BMA-coMMA) latices with particle diameters varying between 160-494 nm and polymer molecular weights of the order 1.25 x 10(4) to 7.55 x 10(4) g/mol were prepared. The rate of polymerization increased with increasing MMA concentration in BMA/MMA ratio, AIBA concentration, DVB crosslink agent, and polymerization temperature. The particle diameter increased with BMA concentration in BMA/MMA ratio, AIBA concentration, and BMA/MMA monomer concentration. The molecular weight increased with BMA concentration in BMA/MMA ratio and BMA/MMA monomer concentration. The glass transition temperature of the latex copolymers decreased with increasing amount of BMA from 375 K for PMMA to 321 K for PBMA. It was, thus, found that the particle diameter and rate of polymerization as well as the polymer molecular weight for surfactant-free emulsion polymerization of BMA and MMA can be controlled easily by controlling the BMA/MMA ratio, BMA/MMA monomer concentration, AIBA concentration, and polymerization temperature.

Contribution of galloylation and polymerization to the antioxidant activity of polyphenols in fish lipid systems.

PubMed

Iglesias, Jacobo; Pazos, Manuel; Lois, Salomé; Medina, Isabel

2010-06-23

Polyphenolic fractions extracted from pine (Pinus pinaster) bark, grape (Vitis vinifera) pomace, and witch hazel (Hamamelis virginiana) bark were selected for investigating the influence of the number of phenolic units, polymerization, and the content of esterified galloyl residues (galloylation) on their efficacy for inhibiting lipid oxidation in fish lipid enriched foodstuffs. Experiments carried out with nongalloylated pine bark fractions with different polymerization degrees demonstrated that the number of catechin residues per molecule modulates their reducing and chelating properties in solution. In real food systems such as bulk fish oil and fish oil-in-water emulsions, the efficacy against lipid oxidation was highly dependent on the physical location of the antioxidant at the oxidative sensitive sites. The lowest polymerized fractions were the most efficient in bulk fish oil samples, whereas proanthocyanidins with an intermediate polymerization degree showed the highest activity in fish oil-in-water emulsions. Galloylation did not influence the antioxidant effectiveness of proanthocyanidins in bulk fish oils. The presence of galloyl groups favored the antioxidant activity of the polyphenols in emulsions, although results indicated that a high degree of galloylation did not improve significantly the activity found with medium galloylated proanthocyanidins. The results obtained in this research provide useful information about the relationship between structure and antioxidant activity in order to design antioxidant additives with application in fish oil-enriched functional foods.

Synthetic Polymers at Interfaces: Monodisperse Emulsions Multiple Emulsions and Liquid Marbles

NASA Astrophysics Data System (ADS)

Sun, Guanqing

The adsorption of polymeric materials at interfaces is an energetically favorable process which is investigated in much diversified fields, such as emulsions, bubbles, foams, liquid marbles. Pickering emulsion, which is emulsion stabilized by solid particles has been investigated for over one century and preparation of Pickering emulsion with narrow size distribution is crucial for both the theoretical study of the stabilization mechanism and practical application, such as templated fabrication of colloidosomes. The precise control over the size and functionality of polymer latices allows the preparation of monodisperse Pickering emulsions with desired sizes through SPG membrane emulsification at rather rapid rate compared to microfludic production. Double or multiple emulsions have long been investigated but its rapid destabilization has always been a major obstacle in applying them into practical applications. The modern living polymerization techniques allow us to prepare polymers with designed structure of block copolymers which makes it possible to prepare ultra-stable multiple emulsions. The precise tuning of the ratio of hydrophobic part over the hydrophilic can unveil the stabilization mechanism. Liquid marble is a new type of materials of which liquid droplets are coated by dry particles. The coating of an outer layer of dry particles renders the liquid droplets non-sticky at solid surface which is useful in transportation of small amount of liquid without leakage at extreme low friction force. The property of liquid marbles relies largely on the stabilizers and the drying condition of polymeric latices is shown to have great influence on the property of liquid marbles. Firstly, an introduction to the interfacial and colloidal science with special attention to topics on emulsions, multiple emulsion and liquid marbles is given in Chapter 1. The unique features of an interface and a discussion on the definition of colloids are introduced prior to the discussion of emulsion stabilization and preparation. A historical review of multiple emulsions is presented subsequently and the stability mechanism is discussed in details with regard to the transportation kinetics of small molecules through the separating membrane of double emulsions. The principle, property and applications of liquid marbles are then summarized. Secondly, the preparation of monodisperse Pickering emulsions stabilized by soft PNIPAM-co-MAA microgels through SPG membrane emulsification is described. The influence of the membrane pore size, pH of the particle dispersion, particle size and the operating parameters of the membrane emulsification device on the size of the emulsion droplets was investigated systematically. The improvement in monodispersity of the emulsion droplets allows us to measure the release profiles of a small molecular dye and a larger nanoparticle through the colloidosomes. It is further demonstrated that the preparation of monodisperse emulsions stabilized by other types of soft particles allows us control the stability of the emulsion with a pH trigger and improved biocompatibility. Thirdly, the preparation of multiple emulsions stabilized by a special designed PEG-b-PS diblock copolymer with desired hydrophobicity by one-step method was presented. The ultra-stability of the as-obtained multiple emulsions was ascribed to the effective steric stabilization of the two interfaces with different polymer configurations at the interfaces. A series of diblock copolymer with increasing PS chain length was then synthesized to investigate the influence of asymmetry ratio on the type of emulsions prepared. It is found that the diblock copolymers with the asymmetry ratio of approximately 1 had the highest power to stabilize multiple emulsions. The multiple emulsions were demonstrated to be a promising platform for controlled release. In the end, particle-stabilized water-in-air liquid marbles were investigated. PSco-MAA nanoparticles synthesized from surfactant-free emulsion polymerization were proved to be effective liquid marble stabilizers. The influence of drying conditions on the properties of liquid marbles was investigated through a macroscopic way. The pH value of the particle dispersion, which influences the protonation states of the particles before freeze-drying, has a profound influence on the property of the stabilized liquid marbles. A brief comment to the future of work of these investigated systems is delivered in the last part.

Glycosylated polyacrylate nanoparticles by emulsion polymerization

PubMed Central

Abeylath, Sampath C.; Turos, Edward

2007-01-01

A selection of glycosylated polyacrylate nanoparticles has been prepared by radical-initiated emulsion polymerization in aqueous media. Using ethyl acrylate as a co-monomer, carbohydrate acrylates were incorporated into the poly(ethyl acrylate) framework to give stable emulsions of glyconanoparticles with an average particle size of around 40 nm. Using this technique a variety of glyconanoparticles were prepared from 3-O-acryloyl-1,2:5,6-di-O-isopropylidene-α-D-glucofuranose, 1-O-acryloyl-2,3:5,6-di-O-isopropylidene-α-D-mannofuranose, 6-O-acryloyl-1,2:3,4-di-O-isopropylidene-α-D-galactopyranose, 2-N-acryloyl-1,3,4,6-tetra-O-acetyl-β-D-glucosamine, 5-O-acryloyl-2,3-isopropylidene-1-methoxy-β-D-ribofuranose and 4-N-acetyl-5’-O-acryloyl-2’,3’-O-isopropylidene cytidine. Scanning electron microscopy, dynamic light scattering and proton NMR analysis of the emulsions indicated essentially 100% incorporation of the carbohydrate acrylate monomer into the polymer with the exception of O-benzyl- and O-benzoyl-protected carbohydrate acrylates, which gave incomplete incorporation. Formation of larger glyconanoparticles of ~80nm with (unprotected) 3-O-acryloyl-D-glucose and 5-O-acryloyl-1-methoxy-β-D-ribofuranose revealed the influence of free hydroxyl groups in the monomer on the particle size during polymerization, a feature which is also apparently dependent on the amount of carbohydrate in the matrix. This methodology allows for a new, simple route to the synthesis of polymeric glyconanoparticles with potential applications in targeted drug delivery and materials development. PMID:18677404

Advanced analysis of polymer emulsions: Particle size and particle size distribution by field-flow fractionation and dynamic light scattering.

PubMed

Makan, Ashwell C; Spallek, Markus J; du Toit, Madeleine; Klein, Thorsten; Pasch, Harald

2016-04-15

Field flow fractionation (FFF) is an advanced fractionation technique for the analyses of very sensitive particles. In this study, different FFF techniques were used for the fractionation and analysis of polymer emulsions/latexes. As model systems, a pure acrylic emulsion and emulsions containing titanium dioxide were prepared and analyzed. An acrylic emulsion polymerization was conducted, continuously sampled from the reactor and subsequently analyzed to determine the particle size, radius of gyration in specific, of the latex particles throughout the polymerization reaction. Asymmetrical flow field-flow fractionation (AF4) and sedimentation field-flow fractionation (SdFFF), coupled to a multidetector system, multi-angle laser light scattering (MALLS), ultraviolet (UV) and refractive index (RI), respectively, were used to investigate the evolution of particle sizes and particle size distributions (PSDs) as the polymerization progressed. The obtained particle sizes were compared against batch-mode dynamic light scattering (DLS). Results indicated differences between AF4 and DLS results due to DLS taking hydration layers into account, whereas both AF4 and SdFFF were coupled to MALLS detection, hence not taking the hydration layer into account for size determination. SdFFF has additional separation capabilities with a much higher resolution compared to AF4. The calculated radii values were 5 nm larger for SdFFF measurements for each analyzed sample against the corresponding AF4 values. Additionally a low particle size shoulder was observed for SdFFF indicating bimodality in the reactor very early during the polymerization reaction. Furthermore, different emulsions were mixed with inorganic species used as additives in cosmetics and coatings such as TiO2. These complex mixtures of species were analyzed to investigate the retention and particle interaction behavior under different AF4 experimental conditions, such as the mobile phase. The AF4 system was coupled online to inductively coupled plasma mass spectrometry (ICP-MS) for elemental speciation and identification of the inorganic additive. SdFFF had a larger separation power to distinguish different particle size populations whereas AF4 had the capability of separating the organic particles and inorganic TiO2 particles, with high resolution. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation of l-phenylalanine-imprinted solid-phase extraction sorbent by Pickering emulsion polymerization and the selective enrichment of l-phenylalanine from human urine.

PubMed

Li, Ji; Hu, Xiaoling; Guan, Ping; Zhang, Xiaoyan; Qian, Liwei; Zhang, Nan; Du, Chunbao; Song, Renyuan

2016-05-01

A novel l-phenylalanine molecularly imprinted solid-phase extraction sorbent was synthesized by the combination of Pickering emulsion polymerization and ion-pair dummy template imprinting. Compared to other polymerization methods, the molecularly imprinted polymers thus prepared exhibit a high specific surface, large pore diameter, and appropriate particle size. The key parameters for solid-phase extraction were optimized, and the result indicated that the molecularly imprinted polymer thus prepared exhibits a good recovery of 98.9% for l-phenylalanine. Under the optimized conditions of the procedure, an analytical method for l-phenylalanine was well established. By comparing the performance of the molecularly imprinted polymer and a commercial reverse-phase silica gel, the obtained molecularly imprinted polymer as an solid-phase extraction sorbent is more suitable, exhibiting high precision (relative standard deviation 3.2%, n = 4) and a low limit of detection (60.0 ± 1.9 nmol·L(-1) ) for the isolation of l-phenylalanine. Based on these results, the combination of the Pickering emulsion polymerization and ion-pair dummy template imprinting is effective for preparing selective solid-phase extraction sorbents for the separation of amino acids and organic acids from complex biological samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

New hybrid latexes from a soybean oil-based waterborne polyurethane and acrylics via emulsion polymerization.

PubMed

Lu, Yongshang; Larock, Richard C

2007-10-01

A series of new waterborne polyurethane (PU)/acrylic hybrid latexes have been successfully synthesized by the emulsion polymerization of acrylic monomers (butyl acrylate and methyl methacrylate) in the presence of a soybean oil-based waterborne PU dispersion using potassium persulfate as an initiator. The waterborne PU dispersion has been synthesized by a polyaddition reaction of toluene 2,4-diisocyanate and a soybean oil-based polyol (SOL). The resulting hybrid latexes, containing 15-60 wt % SOL as a renewable resource, are very stable and exhibit uniform particle sizes of 125 +/- 20 nm as determined by transmittance electronic microscopy. The structure, thermal, and mechanical properties of the resulting hybrid latex films have been investigated by Fourier transform infrared spectroscopy, solid state 13C NMR spectroscopy, dynamic mechanical analysis, extraction, and mechanical testing. Grafting copolymerization of the acrylic monomers onto the PU network occurs during the emulsion polymerization, leading to a significant increase in the thermal and mechanical properties of the resulting hybrid latexes. This work provides a new way of utilizing renewable resources to prepare environmentally friendly hybrid latexes with high performance for coating applications.

Study and Optimization on graft polymerization under normal pressure and air atmospheric conditions, and its application to metal adsorbent

NASA Astrophysics Data System (ADS)

Ueki, Yuji; Chandra Dafader, Nirmal; Hoshina, Hiroyuki; Seko, Noriaki; Tamada, Masao

2012-07-01

Radiation-induced graft polymerization of glycidyl methacrylate (GMA) onto non-woven polyethylene (NWPE) fabric was achieved under normal pressure and air atmospheric conditions, without using unique apparatus such as glass ampoules or vacuum lines. To attain graft polymerization under normal pressure and air atmospheric conditions, the effects of the pre-irradiation dose, pre-irradiation atmosphere, pre-irradiation temperature, de-aeration of GMA-emulsion, grafting atmosphere in a reactor, and dissolved oxygen (DO) concentration in GMA-emulsion on the degree of grafting (Dg) were investigated in detail. It was found that the DO concentration had the strongest influence, the pre-irradiation dose, de-aeration of emulsion and grafting atmosphere had a relatively strong impact, and the pre-irradiation atmosphere and pre-irradiation temperature had the least effect on Dg. The optimum DO concentration before grafting was 2.0 mg/L or less. When a polyethylene bottle was used as a reactor instead of a glass ampoule, graft polymerization under normal pressure and air atmospheric conditions could be achieved under the following conditions; the pre-irradiation dose was more than 50 kGy, the volume ratio of GMA-emulsion to air was 50:1 or less, and the DO concentration in GMA-emulsion during grafting was below 2.0 mg/L. Under these grafting conditions, Dg was controlled within a range of up to 362%. The prepared GMA-grafted NWPE (GMA-g-NWPE) fabric was modified with a phosphoric acid to obtain an adsorbent for heavy metal ions. In the column-mode adsorption tests of Pb(II), the adsorption performance of the produced phosphorylated GMA-g-NWPE fabric (fibrous metal adsorbent) was not essentially dependent on the flow rate of the feed. The breakthrough points of 200, 500, and 1000 h-1 in space velocity were 483, 477 and 462 bed volumes, and the breakthrough capacities of the three flow rates were 1.16, 1.15 and 1.16 mmol-Pb(II)/g-adsorbent.

Photopolymerization Of Levitated Droplets

NASA Technical Reports Server (NTRS)

Rembaum, Alan; Rhim, Won-Kyu; Hyson, Michael T.; Chang, Manchium

1989-01-01

Experimental containerless process combines two established techniques to make variety of polymeric microspheres. In single step, electrostatically-levitated monomer droplets polymerized by ultraviolet light. Faster than multiple-step emulsion polymerization process used to make microspheres. Droplets suspended in cylindrical quadrupole electrostatic levitator. Alternating electrostatic field produces dynamic potential along axis. Process enables tailoring of microspheres for medical, scientific, and industrial applications.

Non-coalescence of oppositely charged droplets in pH-sensitive emulsions

PubMed Central

Liu, Tingting; Seiffert, Sebastian; Thiele, Julian; Abate, Adam R.; Weitz, David A.; Richtering, Walter

2012-01-01

Like charges stabilize emulsions, whereas opposite charges break emulsions. This is the fundamental principle for many industrial and practical processes. Using micrometer-sized pH-sensitive polymeric hydrogel particles as emulsion stabilizers, we prepare emulsions that consist of oppositely charged droplets, which do not coalesce. We observe noncoalescence of oppositely charged droplets in bulk emulsification as well as in microfluidic devices, where oppositely charged droplets are forced to collide within channel junctions. The results demonstrate that electrostatic interactions between droplets do not determine their stability and reveal the unique pH-dependent properties of emulsions stabilized by soft microgel particles. The noncoalescence can be switched to coalescence by neutralizing the microgels, and the emulsion can be broken on demand. This unusual feature of the microgel-stabilized emulsions offers fascinating opportunities for future applications of these systems. PMID:22203968

Characterization of cinematographic films by Laser Induced Breakdown Spectroscopy

NASA Astrophysics Data System (ADS)

Gaspard, S.; Oujja, M.; Rebollar, E.; Abrusci, C.; Catalina, F.; Castillejo, M.

2007-12-01

The emulsion-coated transparent plastic-base film has been the main carrier for production and preservation of motion picture contents since the 19th century. The knowledge of the composition of black and white silver gelatine cinematographic films is of great importance for the characterization of the photographic process and for identifying the optimum conditions for conservation. A cinematographic film is a multi-component system that consists of a layer of photographic emulsion overcoating a polymeric support (plasticized cellulose triacetate) and a protective transparent cross-linked gelatine layer coating the emulsion. In the present work, Laser Induced Breakdown Spectroscopy (LIBS) is used to characterize the composition of the materials of cinematographic films. LIB spectra of film samples and of different individual film components, polymeric support and reference gelatines, were acquired in vacuum by excitation at 266 nm (Q-switched Nd:YAG laser, 6 ns, 10 Hz). In the cinematographic film, silver lines from the light-sensitive silver halide salts of the photographic emulsion are accompanied by iron, lead, chrome and phosphorus lines. Iron and lead are constituents of film developers, chrome is included in the composition of the hardening agents and phosphorus has its origin in the plasticizer used in the polymeric support. By applying successive pulses on the same spot of the film sample, it was possible to observe through stratigraphic analysis the different layers composition. Additionally, the results obtained reveal the analytical capacity of LIBS for the study and classification of the different gelatine types and qualities used for the protecting layer and the photographic emulsion.

Emulsifier-free emulsion polymerization produces highly charged, monodisperse particles for near infrared photonic crystals.

PubMed

Reese, Chad E; Asher, Sanford A

2002-04-01

We have developed emulsifier-free, emulsion polymerization recipes for the synthesis of highly charged, monodisperse latex particles of diameters between 500 and 1100 nm. These latexes consist of poly[styrene-(co-2-hydroxyethyl methacrylate)] spherical particles whose surfaces are functionalized with sulfate and carboxylic acid groups. These highly charged, monodisperse particles readily self-assemble into robust, three-dimensionally ordered crystalline colloidal array photonic crystals that Bragg diffract light in the near infrared spectral region. By altering the particle number density, the diffraction wavelength can be tuned from approximately 1000 to approximately 4000 nm.

Preparation, characterization, and in vitro gastrointestinal digestibility of oil-in-water emulsion-agar gels.

PubMed

Wang, Zheng; Neves, Marcos A; Kobayashi, Isao; Uemura, Kunihiko; Nakajima, Mitsutoshi

2013-01-01

Soybean oil-in-water (O/W) emulsion-agar gel samples were prepared and their digestibility evaluated by using an in vitro gastrointestinal digestion model. Emulsion-agar sols were obtained by mixing the prepared O/W emulsions with a 1.5 wt % agar solution at 60 °C, and their subsequent cooling at 5 °C for 1 h formed emulsion-agar gels. Their gel strength values increased with increasing degree of polymerization of the emulsifiers, and the relative gel strength increased in the case of droplets with an average diameter smaller than 700 nm. Flocculation and coalescence of the released emulsion droplets depended strongly on the emulsifier type; however, the emulsifier type hardly affected the ζ-potential of emulsion droplets released from the emulsion-agar gels during in vitro digestion. The total FFA content released from each emulsion towards the end of the digestion period was nearly twice that released from the emulsion-agar gel, indicating that gelation of the O/W emulsion may have delayed lipid hydrolysis.

Preparation of Pickering Double Emulsions Using Block Copolymer Worms

PubMed Central

2015-01-01

The rational formulation of Pickering double emulsions is described using a judicious combination of hydrophilic and hydrophobic block copolymer worms as highly anisotropic emulsifiers. More specifically, RAFT dispersion polymerization was utilized to prepare poly(lauryl methacrylate)–poly(benzyl methacrylate) worms at 20% w/w solids in n-dodecane and poly(glycerol monomethacrylate)–poly(2-hydroxypropyl methacrylate)–poly(benzyl methacrylate) worms at 13% w/w solids in water by polymerization-induced self-assembly (PISA). Water-in-oil-in-water (w/o/w) double emulsions can be readily prepared with mean droplet diameters ranging from 30 to 80 μm using a two-stage approach. First, a w/o precursor emulsion comprising 25 μm aqueous droplets is prepared using the hydrophobic worms, followed by encapsulation within oil droplets stabilized by the hydrophilic worms. The double emulsion droplet diameter and number of encapsulated water droplets can be readily varied by adjusting the stirring rate employed during the second stage. For each stage, the droplet volume fraction is relatively high at 0.50. The double emulsion nature of the final formulation was confirmed by optical and fluorescence microscopy studies. Such double emulsions are highly stable to coalescence, with little or no change in droplet diameter being detected over storage at 20 °C for 10 weeks as judged by laser diffraction. Preliminary experiments indicate that the complementary o/w/o emulsions can also be prepared using the same pair of worms by changing the order of homogenization, although somewhat lower droplet volume fractions were required in this case. Finally, we demonstrate that triple and even quadruple emulsions can be formulated using these new highly anisotropic Pickering emulsifiers. PMID:25834923

Investigation of Four Different Laponite Clays as Stabilizers in Pickering Emulsion Polymerization.

PubMed

Brunier, Barthélémy; Sheibat-Othman, Nida; Chniguir, Mehdi; Chevalier, Yves; Bourgeat-Lami, Elodie

2016-06-21

Clay-armored polymer particles were prepared by emulsion polymerization in the presence of Laponite platelets that adsorb at the surface of latex particles and act as stabilizers during the course of the polymerization. While Laponite RDS clay platelets are most often used, the choice of the type of clay still remains an open issue that is addressed in the present article. Four different grades of Laponite were investigated as stabilizers in the emulsion polymerization of styrene. First, the adsorption isotherms of the clays, on preformed polystyrene particles, were determined by ICP-AES analysis of the residual clay in the aqueous phase. Adsorption of clay depended on the type of clay at low concentrations corresponding to adsorption as a monolayer. Adsorption of clay particles as multilayers was observed for all the grades above a certain concentration under the considered ionic strength (mainly due to the initiator ionic species). The stabilization efficiency of these clays was investigated during the polymerization reaction (free of any other stabilizer). The clays did not have the same effect on stabilization, which was related to differences in their compositions and in their adsorption isotherms. The different grades led to different polymer particles sizes and therefore to different polymerization reaction rates. Laponite RDS and S482 gave similar results, ensuring the best stabilization efficiency and the fastest reaction rate; the number of particles increased as the clay concentration increased. Stabilization with Laponite XLS gave the same particles size and number as the latter two clays at low clay concentrations, but it reached an upper limit in the number of nucleated polymer particles at higher concentrations indicating a decrease of stabilization efficiency at high concentrations. Laponite JS did not ensure a sufficient stability of the polymer particles, as the polymerization results were comparable to a stabilizer-free polymerization system.

The influence of droplet size on the stability, in vivo digestion, and oral bioavailability of vitamin E emulsions.

PubMed

Parthasarathi, S; Muthukumar, S P; Anandharamakrishnan, C

2016-05-18

Vitamin E (α-tocopherol) is a nutraceutical compound, which has been shown to possess potent antioxidant and anticancer activity. However, its biological activity may be limited by its poor bioavailability. Colloidal delivery systems have shown wide applications in the food and pharmaceutical industries to deliver lipophilic bioactive compounds. In this study, we have developed conventional and nanoemulsions of vitamin E from food grade ingredients (sunflower oil, saponin, and water) and showed the nanoemulsion formulation increased the oral bioavailability when compared to the conventional emulsion. The mean droplet diameters in the nano and conventional emulsions were 0.277 and 1.285 μm, respectively. The stability of the emulsion formulation after thermal processing, long-term storage at different temperatures, mechanical stress and in plasma was determined. The results showed that the saponin coated nanoemulsion was stable to droplet coalescence during thermal processing (30-90 °C), long-term storage and mechanical stress when compared to the conventional emulsion. The biological fate of the emulsion formulations were studied using male Wistar rats as an animal model. The emulsion droplet stability during passage through the gastrointestinal tract was evaluated by their introduction into rat stomachs. Microscopy was used to investigate the structural changes that occurred during digestion. Both the conventional emulsion and nanoemulsion formulations showed strong evidence of droplet flocculation and coalescence during in vivo digestion. The in vivo oral bioavailability study revealed that vitamin E in a nanoemulsion form showed a 3-fold increase in the AUC when compared to the conventional emulsion. The information reported in this study will facilitate the design of colloidal delivery systems using nanoemulsion formulations.

Differences in antioxidant activity between two rice protein concentrates in an oil-in-water emulsion

USDA-ARS?s Scientific Manuscript database

Two formulations of rice protein concentrates (RPC) derived from brown rice were evaluated for their antioxidant activity in bulk oil and in oil-in-water emulsions. Bulk oils were mixed with RPC and heated to 180°C, and total polar compounds and triacylglycerol polymerization were measured. Minimal ...

Annatto Polymeric Microparticles: Natural Product Encapsulation by the Emulsion-Solvent Evaporation Method

ERIC Educational Resources Information Center

Teixeira, Zaine; Duran, Nelson; Guterres, Silvia S.

2008-01-01

In this experiment, the extract from annatto seeds was encapsulated in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) particles by the emulsion-solvent evaporation method. The particles were washed and centrifuged to remove excess stabilizer and then freeze-dried. The main compound of annatto seeds, bixin, has antioxidant properties as well…

Preparation of Fe 3O 4/poly(styrene-butyl acrylate-[2-(methacryloxy)ethyl]trimethylammonium chloride) by emulsifier-free emulsion polymerization and its interaction with DNA

NASA Astrophysics Data System (ADS)

Li, Xiaolong; Liu, Guoqiang; Yan, Wei; Chu, Paul K.; Yeung, Kelvin W. K.; Wu, Shuilin; Yi, Changfeng; Xu, Zushun

2012-04-01

Cationic magnetic polymer particles Fe3O4/poly(styrene-butyl acrylate-[2-(methacryloxy)ethyl]trimethylammonium chloride), a type of potential gene carrier, were prepared by emulsifier-free emulsion polymerization with oleic acid modified magnetite Fe3O4, styrene, butyl acrylate and [2-(methacryloxy)ethyl]trimethylammonium chloride) (METAC). The morphology of the particles was characterized by transmission electron microscopy and the composites of particles were characterized by FT-IR spectroscopy, X-ray diffraction. These results showed that magnetic particles were well dispersed in polymers with the content of about 15%(wt/wt). The composites exhibited superparamagnetism and possessed a certain level of magnetic response. The interactions between the particles with calf-thymus DNA (ct DNA) were confirmed by zeta potential measurement, UV-vis spectroscopy and fluorescence spectroscopy. The DNA-binding capacity determined by the agarose gel electrophoresis showed good binding capacity of the emulsion to DNA. These results suggested the potential of the cationic magnetic polymer emulsion as gene target delivery carrier.

Fabrication and evaluation of magnetic/hollow double-shelled imprinted sorbents formed by Pickering emulsion polymerization.

PubMed

Pan, Jianming; Li, Linzi; Hang, Hui; Wu, Runrun; Dai, Xiaohui; Shi, Weidong; Yan, Yongsheng

2013-06-25

Magnetic/hollow double-shelled imprinted polymers (MH-MIPs) were synthesized by Pickering emulsion polymerization. In this method, attapulgite (ATP) particles were used as stabilizers to establish a stable oil-in-water emulsion, and a few hydrophilic Fe3O4 nanoparticles were allowed to be magnetic separation carriers. The imprinting system was fabricated by radical polymerization in the presence of the functional and polymeric monomers in the oil phase. The results of characterization indicated that MH-MIPs exhibited magnetic sensitivity (Ms = 4.76 emu g(-1)), thermal stability (especially below 200 °C), and hollow structure and were composed of exterior ATP shells and interior imprinted polymers shells. Then MH-MIPs were evaluated as sorbents for the selective binding of λ-cyhalothrin as a result of their magnetism, enhanced mechanical strength, hydrophilic surface, and recognition ability. The kinetic properties of MH-MIPs were well described by the pseudo-second-order equation, indicating that the chemical process could be the rate-limiting step in the adsorption process for λ-cyhalothrin. The equilibrium adsorption capacity of MH-MIPs was 60.06 μmol g(-1) at 25 °C, and the Langmuir isotherm model gave a better fit to the experimental data, indicating the monolayer molecular adsorption for λ-cyhalothrin. The selective recognition experiments also demonstrated the high affinity and selectivity of MH-MIIPs toward λ-cyhalothrin over fenvalerate and diethyl phthalate.

Magnetic properties of the Fe{sup II} spin crossover complex in emulsion polymerization of trifluoroethylmethacrylate using poly(vinyl alcohol)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Atsushi, E-mail: suzuki@mat.usp.ac.j; Iguchi, Motoi; Oku, Takeo

2010-04-15

Influence of chemical substitution in the Fe{sup II} spin crossover complex on magnetic properties in emulsion polymerization of trifluoroethylmethacrylate using poly(vinyl alcohol) as a protective colloid was investigated near its high spin/low spin (HS/LS) phase transition. The obvious bi-stability of the HS/LS phase transition was considered by the identification of multiple spin states between the quintet (S=2) states to single state (S=0) across the excited triplet state (S=1). Magnetic parameters of gradual shifts of anisotropy g-tensor supported by the molecular distortion of the spin crossover complex would arise from a Jahn-Teller effect regarding ligand field theory on the basis ofmore » a B3LYP density functional theory using electron spin resonance (ESR) spectrum and X-ray powder diffraction. - Graphical abstract: AFM surface image of the emulsion particles with the spin crossover complex.« less

Synthesis of mesoporous poly(melamine-formaldehyde) particles by inverse emulsion polymerization.

PubMed

Schwarz, Dana; Weber, Jens

2017-07-15

Mesoporous poly(melamine-formaldehyde) (MF) particles with surface areas of up to 200m 2 g -1 were synthesized by an inverse emulsion polymerization using dodecane and Span80® as continuous phase. The finer details of the shape control (using emulsion techniques) and the porosity control (using silica nanoparticles as hard-template) are discussed. The impact of phase-separation processes on the observable porosity of the 20-200µm sized spherical particles is analysed by gas sorption methods and electron microscopy. The high density of amine and triazine functional groups in the porous MF particles make the material a promising adsorber for heavy metal ions and methylene blue. In a preliminary column experiment, the synthesized material exhibited a total capacity of 2.54mmol/g (≙ 812.4mg/g) for the adsorption of methylene blue. Copyright © 2017 Elsevier Inc. All rights reserved.

Fluorescent Labeling and Biodistribution of Latex Nanoparticles Formed by Surfactant-Free RAFT Emulsion Polymerization.

PubMed

Poon, Cheuk Ka; Tang, Owen; Chen, Xin-Ming; Kim, Byung; Hartlieb, Matthias; Pollock, Carol A; Hawkett, Brian S; Perrier, Sébastien

2017-10-01

The authors report the preparation of a novel range of functional polyacrylamide stabilized polystyrene nanoparticles, obtained by surfactant-free reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization, their fluorescent tagging, cellular uptake, and biodistribution. The authors show the versatility of the RAFT emulsion process for the design of functional nanoparticles of well-defined size that can be used as drug delivery vectors. Functionalization with a fluorescent tag offers a useful visualization tool for tracing, localization, and clearance studies of these carriers in biological models. The studies are carried out by labeling the sterically stabilized latex particles chemically with rhodamine B. The fluorescent particles are incubated in a healthy human renal proximal tubular cell line model, and intravenously injected into a mouse model. Cellular localization and biodistribution of these particles on the biological models are explored. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of Paraffin@Poly(styrene-co-acrylic acid) Phase Change Nanocapsules via Combined Miniemulsion/Emulsion Polymerization.

PubMed

Zhang, Feng; Liu, Tian-Yu; Hou, Gui-Hua; Guan, Rong-Feng; Zhang, Jun-Hao

2018-06-01

The fast development of solid-liquid phase change materials calls for nanomaterials with large specific surface area for rapid heat transfer and encapsulation of phase change materials to prevent potential leakage. Here we report a combined miniemulsion/emulsion polymerization method to prepare poly(styrene-co-acrylic acid)-encapsulated paraffin (paraffin@P(St-co-AA)) nanocapsules. The method could suppress the shortcomings of common miniemulsion polymerization (such as evaporation of monomer and decomposition of initiator during ultrasonication). The paraffin@P(St-co-AA) nanocapsules are uniform in size and the polymer shell can be controlled by the weight ratio of St to paraffin. The phase change behavior of the nanocapsules is similar to that of pure paraffin. We believe our method can also be utilized to synthesize other core-shell phase change materials.

Synthesis and Characterization of Novel Fluorine-Containing Water-Based Antirust Coating

NASA Astrophysics Data System (ADS)

Wang, Huiru; Wang, Xin; Zhao, Xiongyan

2018-01-01

A fluorine-containing polyacrylate copolymer emulsion was synthesized by a seed emulsion polymerization method, in which styrene(St) and butyl acrylate (BA) were used as main monomers and dodecafluoroheptyl methacrylate(DFMA) as fluorine-containing monomer. The structure and properties were characterized by Fourier transform infrared spectrum (FT-IR), scanning electron microscopy (SEM), particle size analysis, differential scanning calorimetry (DSC). The FTIR results showed that DFMA was effectively involved in the emulsion copolymerization, and the formed emulsion particles had a narrow particle size distribution. From the results salt spray test presented, it seems when the content of DFMA was 5wt% anti-rust performance of emulsion is relatively better. DSC and TGA also showed that their film exhibited higher thermal stability than that of fluorine-free emulsion.

An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions.

PubMed

Ruan, Guihua; Wu, Zhenwei; Huang, Yipeng; Wei, Meiping; Su, Rihui; Du, Fuyou

2016-04-22

A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of Nα-benzoyl-l-arginine ethyl ester to Nα-benzoyl-l-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast and easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas. Copyright © 2016 Elsevier Inc. All rights reserved.

Structural micro-porous carbon anode for rechargeable lithium-ion batteries

DOEpatents

Delnick, Frank M.; Even, Jr., William R.; Sylwester, Alan P.; Wang, James C. F.; Zifer, Thomas

1995-01-01

A secondary battery having a rechargeable lithium-containing anode, a cathode and a separator positioned between the cathode and anode with an organic electrolyte solution absorbed therein is provided. The anode comprises three-dimensional microporous carbon structures synthesized from polymeric high internal phase emulsions or materials derived from this emulsion source, i.e., granules, powders, etc.

Characterization of Chemically and Thermally Treated Oil-in-Water Heteroaggregates and Comparison to Conventional Emulsions.

PubMed

Maier, Christiane; Reichert, Corina L; Weiss, Jochen

2016-10-01

Heteroaggregated oil-in-water (O/W) emulsions formed by targeted combination of oppositely charged emulsion droplets were proposed to be used for the modulation of physical properties of food systems, ideally achieving the formation of a particulate 3-dimensional network at comparably low-fat content. In this study, rheological properties of Quillaja saponins (QS), sugar beet pectin (SBP), and whey protein isolate (WPI) stabilized conventional and heteroaggregated O/W emulsions at oil contents of 10% to 60% (w/w) were investigated. Selected systems having an oil content of 30% (w/w) and different particle sizes (d 43 ≤ 1.1 or ≥16.7 μm) were additionally subjected to chemical (genipin or glutaraldehyde) and thermal treatments, aiming to increase network stability. Subsequently, their rheological properties and stability were assessed. Yield stresses (τ 0 ) of both conventional and heteroaggregated O/W emulsions were found to depend on emulsifier type, oil content, and initial droplet size. For conventional emulsions, high yield stresses were only observed for SBP-based emulsions (τ 0 , SBP approximately 157 Pa). Highest yield stresses of heteroaggregates were observed when using small droplets stabilized by SBP/WPI (approximately 15.4 Pa), being higher than those of QS/WPI (approximately 1.6 Pa). Subsequent treatments led to significant alterations in rheological properties for SBP/WPI systems, with yield stresses increasing 29-fold (glutaraldehyde) and 2-fold (thermal treatment) compared to untreated heteroaggregates, thereby surpassing yield stresses of similarly treated conventional SBP emulsions. Genipin-driven treatments proved to be ineffective. Results should be of interest to food manufacturers wishing to design viscoelastic food emulsion based systems at lower oil droplet contents. © 2016 Institute of Food Technologists®.

Fluorescence correlation spectroscopy directly monitors coalescence during nanoparticle preparation.

PubMed

Schaeffel, David; Staff, Roland Hinrich; Butt, Hans-Juergen; Landfester, Katharina; Crespy, Daniel; Koynov, Kaloian

2012-11-14

Dual color fluorescence cross-correlation spectroscopy (DC FCCS) experiments were conducted to study the coalescence and aggregation during the formation of nanoparticles. To assess the generality of the method, three completely different processes were selected to prepare the nanoparticles. Polymeric nanoparticles were formed either by solvent evaporation from emulsion nanodroplets of polymer solutions or by miniemulsion polymerization. Inorganic nanocapsules were formed by polycondensation of alkoxysilanes at the interface of nanodroplets. In all cases, DC FCCS provided fast and unambiguous information about the occurrence of coalescence and thus a deeper insight into the mechanism of nanoparticle formation. In particular, it was found that coalescence played a minor role for the emulsion-solvent evaporation process and the miniemulsion polymerization, whereas substantial coalescence was detected during the formation of the inorganic nanocapsules. These findings demonstrate that DC FCCS is a powerful tool for monitoring nanoparticles genesis.

Synthesis of porous poly(styrene-co-acrylic acid) microspheres through one-step soap-free emulsion polymerization: whys and wherefores.

PubMed

Yan, Rui; Zhang, Yaoyao; Wang, Xiaohui; Xu, Jianxiong; Wang, Da; Zhang, Wangqing

2012-02-15

Synthesis of porous poly(styrene-co-acrylic acid) (PS-co-PAA) microspheres through one-step soap-free emulsion polymerization is reported. Various porous PS-co-PAA microspheres with the particle size ranging from 150 to 240 nm and with the pore size ranging from 4 to 25 nm are fabricated. The porous structure of the microspheres is confirmed by the transmission electron microscopy measurement and Brunauer-Emmett-Teller (BET) analysis. The reason for synthesis of the porous PS-co-PAA microspheres is discussed, and the phase separation between the encapsulated hydrophilic poly(acrylic acid) segment and the hydrophobic polystyrene domain within the PS-co-PAA microspheres is ascribed to the pore formation. The present synthesis of the porous PS-co-PAA microspheres is anticipated to be a new and convenient way to fabricate porous polymeric particles. Copyright © 2011 Elsevier Inc. All rights reserved.

Synthesis and characterization of magnetic and non-magnetic core-shell polyepoxide micrometer-sized particles of narrow size distribution.

PubMed

Omer-Mizrahi, Melany; Margel, Shlomo

2009-01-15

Core polystyrene microspheres of narrow size distribution were prepared by dispersion polymerization of styrene in a mixture of ethanol and 2-methoxy ethanol. Uniform polyglycidyl methacrylate/polystyrene core-shell micrometer-sized particles were prepared by emulsion polymerization at 73 degrees C of glycidyl methacrylate in the presence of the core polystyrene microspheres. Core-shell particles with different properties (size, surface morphology and composition) have been prepared by changing various parameters belonging to the above seeded emulsion polymerization process, e.g., volumes of the monomer glycidyl methacrylate and the crosslinker monomer ethylene glycol dimethacrylate. Magnetic Fe(3)O(4)/polyglycidyl methacrylate/polystyrene micrometer-sized particles were prepared by coating the former core-shell particles with magnetite nanoparticles via a nucleation and growth mechanism. Characterization of the various particles has been accomplished by routine methods such as light microscopy, SEM, FTIR, BET and magnetic measurements.

A Study of Functional Polymer Colloids Prepared Using Thiol-Ene/Yne Click Chemistry

NASA Astrophysics Data System (ADS)

Durham, Olivia Z.

This project demonstrates the first instance of thiol-ene chemistry as the polymerization method for the production of polymer colloids in two-phase heterogeneous suspensions, miniemulsions, and emulsions. This work was also expanded to thiol-yne chemistry for the production of polymer particles containing increased crosslinking density. The utility of thiol-ene and thiol-yne chemistries for polymerization and polymer modification is well established in bulk systems. These reactions are considered 'click' reactions, which can be defined as processes that are both facile and simple, offering high yields with nearly 100% conversion, no side products, easy product separation, compatibility with a diverse variety of commercially available starting materials, and orthogonality with other chemistries. In addition, thiol-ene and thiol-yne chemistry follow a step-growth mechanism for the development of highly uniform polymer networks, where polymer growth is dependent on the coupling of functional groups. These step-growth polymerization systems are in stark contrast to the chain-growth mechanisms of acrylic and styrenic monomers that have dominated the field of conventional heterogeneous polymerizations. Preliminary studies evaluated the mechanism of particle production in suspension and miniemulsion systems. Monomer droplets were compared to the final polymer particles to confirm that particle growth occurred through the polymerization of monomer droplets. Additional parameters examined include homogenization energy (mechanical mixing), diluent species and concentration, and monomer content. These reactions were conducted using photoinitiation to yield particles in a matter of minutes with diameters in the size range of several microns to hundreds of microns in suspensions or submicron particles in miniemulsions. Improved control over the particle size and size distribution was examined through variation of reaction parameters. In addition, a method of seeded suspension polymerization was attempted. This project was further expanded through an extensive evaluation of stabilizers in thiol-ene suspension polymerizations. The scope of stabilizers used included synthetic surfactants (ionic and nonionic), natural gums, and colloidal silica (Pickering stabilization). Suspension polymerizations were further expanded to include thiol-yne chemistry for the evaluation of polymer composition and thermal properties. In addition, polymer particles with excess ene, yne, or thiol functionality were successfully developed to demonstrate the potential for further functionalization. The self-limiting behavior of thiol-ene/yne reactions allows for successful synthesis of functional polymer colloids using off-stoichiometric amounts of monomers. This capacity to control functionality is illustrated through the creation of fluorescent polymer particles using both an in situ thiol-ene polymerization reaction with a vinyl chromophore as well as through post-polymerization modification of thiol-ene and thiol-yne polymers with excess thiol functionality via thiol-isocyanate chemistry. To produce smaller polymer particles without the need for intense homogenization energy or high stabilizer concentrations, an emulsion polymerization system was implemented using a water soluble-thermal initiator. It was found that unlike thiol-ene suspensions, which are limited to crosslinked systems, thiol-ene emulsion polymerizations allowed for the production of polymer particles comprised of either crosslinked or linear polymer networks. For the crosslinked systems, various anionic SDS surfactant concentrations were examined to observe the influence on particle size. In linear polymer systems, variations in polymer composition were examined. Preliminary studies performed with a monomer with an ethylene glycol-like structure indicated that the synthesis of polymer particles with narrower size distributions compared to any of the other emulsion compositions was possible. Finally, thiol-ene chemistry was also employed toward the synthesis of degradable polyanhydride polymer particles. Unlike the aforementioned studies, the approach to particle synthesis was conducted by using a premade thiol-ene polymer. Various linear thiol-ene polyanhydrides were emulsified in water or buffered solutions via sonication. Polymer latex was obtained upon solvent evaporation of the dichloromethane (DCM) solvent used to solubilize the polymer. In this work, variation of polymer composition as well as degradation was examined. Additional experiments included a study of the release of Rhodamine B dye, functionalization of the linear polymers, and studies involving the delay of degradation through the incorporation of crosslinking in the polymer particles. The projects presented herein provide an innovative approach to the synthesis of polymer colloids using thiol-ene and thiol-yne 'click' chemistry in both heterogeneous polymerizations as well as through solvent evaporation of premade polymer solutions. Polymer colloids prove to be an area of great interest for numerous applications that encompass various areas involving biomedical and industrial technologies including paints and coatings, cosmetics, diagnostics, and drug delivery. Improvements in methods of chemical synthesis as well as advances in the tailoring of material properties are of utmost importance for the ever increasing demands of new technologies and educational enlightenment.

Flow curve analysis of a Pickering emulsion-polymerized PEDOT:PSS/PS-based electrorheological fluid

NASA Astrophysics Data System (ADS)

Kim, So Hee; Choi, Hyoung Jin; Leong, Yee-Kwong

2017-11-01

The steady shear electrorheological (ER) response of poly(3, 4-ethylenedioxythiophene): poly(styrene sulfonate)/polystyrene (PEDOT:PSS/PS) composite particles, which were initially fabricated from Pickering emulsion polymerization, was tested with a 10 vol% ER fluid dispersed in a silicone oil. The model independent shear rate and yield stress obtained from the raw torque-rotational speed data using a Couette type rotational rheometer under an applied electric field strength were then analyzed by Tikhonov regularization, which is the most suitable technique for solving an ill-posed inverse problem. The shear stress-shear rate data also fitted well with the data extracted from the Bingham fluid model.

Penicillin-Bound Polyacrylate Nanoparticles: Restoring the Activity of β-Lactam Antibiotics Against MRSA

PubMed Central

Reddy, G. Suresh Kumar; Greenhalgh, Kerriann; Ramaraju, Praveen; Abeylath, Sampath C.; Jang, Seyoung; Dickey, Sonja; Lim, Daniel V.

2007-01-01

This report describes the preparation of antibacterially-active emulsified polyacrylate nanoparticles in which a penicillin antibiotic is covalently conjugated onto the polymeric framework. These nanoparticles were prepared in water by emulsion polymerization of an acrylated penicillin analogue pre-dissolved in a 7:3 (w:w) mixture of butyl acrylate and styrene in the presence of sodium dodecyl sulfate (surfactant) and potassium persulfate (radical initiator). Dynamic light scattering analysis and atomic force microscopy images show that the emulsions contain nanoparticles of approximately 40 nm in diameter. The nanoparticles have equipotent in vitro antibacterial properties against methicillin-susceptible and methicillin-resistant forms of Staphylococcus aureus and indefinite stability towards β-lactamase. PMID:17420125

Structural micro-porous carbon anode for rechargeable lithium-ion batteries

DOEpatents

Delnick, F.M.; Even, W.R. Jr.; Sylwester, A.P.; Wang, J.C.F.; Zifer, T.

1995-06-20

A secondary battery having a rechargeable lithium-containing anode, a cathode and a separator positioned between the cathode and anode with an organic electrolyte solution absorbed therein is provided. The anode comprises three-dimensional microporous carbon structures synthesized from polymeric high internal phase emulsions or materials derived from this emulsion source, i.e., granules, powders, etc. 6 figs.

An investigation into the characteristics and drug release properties of multiple W/O/W emulsion systems containing low concentration of lipophilic polymeric emulsifier.

PubMed

Vasiljevic, Dragana; Parojcic, Jelena; Primorac, Marija; Vuleta, Gordana

2006-02-17

Multiple W/O/W emulsions with high content of inner phase (Phi1=Phi2=0.8) were prepared using relatively low concentrations of lipophilic polymeric primary emulsifier, PEG 30-dipolyhydroxystearate, and diclofenac diethylamine (DDA) as a model drug. The investigated formulations were characterized and their stability over the time was evaluated by dynamic and oscillatory rheological measurements, microscopic analysis and in vitro drug release study. In vitro release profiles of the selected model drug were evaluated in terms of the effective diffusion coefficients and flux of the released drug. The multiple emulsion samples exhibited good stability during the ageing time. Concentration of the lipophilic primary emulsifier markedly affected rheological behaviour as well as the droplet size and in vitro drug release kinetics of the investigated systems. The multiple emulsion systems with highest concentration (2.4%, w/w) of the primary emulsifier had the lowest droplet size and the highest apparent viscosity and highest elastic characteristics. Drug release data indicated predominately diffusional drug release mechanism with sustained and prolonged drug release accomplished with 2.4% (w/w) of lipophilic emulsifier employed.

Radiation induced emulsion graft polymerization of 4-vinylpyridine onto PE/PP nonwoven fabric for As(V) adsorption

NASA Astrophysics Data System (ADS)

Akkaş Kavaklı, Pınar; Kavaklı, Cengiz; Seko, Noriaki; Tamada, Masao; Güven, Olgun

2016-10-01

A novel nonwoven fabric adsorbent having 4-vinylpyridine functional groups was prepared by using radiation-induced emulsion graft polymerization method and grafting 4-vinylpyridine monomer onto a polyethylene-coated polypropylene nonwoven fabric (NWF) in aqueous emulsion solution. The grafting conditions of the 4-vinylpyridine monomer onto the NWF were optimised and 150% Dg VP-g-NWF was prepared using 30 kGy pre-irradiation dose, 5% VP monomer concentration and 0.5% (w/w) Tween 20 in aqueous emulsion. Grafted 4-vinylpyridine chains on the NWF were then quaternized for the preparation of QVP-g-NWF adsorbent. All fabric structures were characterized by using Fourier-transform infrared spectrometer, x-ray photoelectron spectrometer and scanning electron microscope. QVP-g-NWF adsorbent was used in batch adsorption experiments for As(V) ions by studying the pH, contact time, and initial As(V) ion concentration parameters. Results showed that QVP-g-NWF adsorbent has significant As(V) adsorption and experimental As(V) adsorption capacity was 98.04 mg As(V)/g polymer from 500 mg/L initial As(V) concentration at pH 7.00.

ABC Triblock Copolymer Worms: Synthesis, Characterization, and Evaluation as Pickering Emulsifiers for Millimeter-Sized Droplets

PubMed Central

2016-01-01

Polymerization-induced self-assembly (PISA) is used to prepare linear poly(glycerol monomethacrylate)–poly(2-hydroxypropyl methacrylate)–poly(benzyl methacrylate) [PGMA–PHPMA–PBzMA] triblock copolymer nano-objects in the form of a concentrated aqueous dispersion via a three-step synthesis based on reversible addition–fragmentation chain transfer (RAFT) polymerization. First, GMA is polymerized via RAFT solution polymerization in ethanol, then HPMA is polymerized via RAFT aqueous solution polymerization, and finally BzMA is polymerized via “seeded” RAFT aqueous emulsion polymerization. For certain block compositions, highly anisotropic worm-like particles are obtained, which are characterized by small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The design rules for accessing higher order morphologies (i.e., worms or vesicles) are briefly explored. Surprisingly, vesicular morphologies cannot be accessed by targeting longer PBzMA blocks—instead, only spherical nanoparticles are formed. SAXS is used to rationalize these counterintuitive observations, which are best explained by considering subtle changes in the relative enthalpic incompatibilities between the three blocks during the growth of the PBzMA block. Finally, the PGMA–PHPMA–PBzMA worms are evaluated as Pickering emulsifiers for the stabilization of oil-in-water emulsions. Millimeter-sized oil droplets can be obtained using low-shear homogenization (hand-shaking) in the presence of 20 vol % n-dodecane. In contrast, control experiments performed using PGMA–PHPMA diblock copolymer worms indicate that these more delicate nanostructures do not survive even these mild conditions. PMID:27795581

USING ACID-RESISTANT PHOTOSENSITIVE EMULSIONS TO OBTAIN LOCAL INHOMOGENEITIES WITH A HIGH RESOLVING POWER ON MONOCRYSTALS AND FILMS OF GERMANIUM AND SILICON (PRIMENENIE KISLOTOSTOYKHIKH SVETOCHUVSTVITELNYKH EMULSII DLYA POLUCHENIYA LOKALNYKH NEODNORODNOSTEI S VYSOKIM RAZRESHENIEM NA MONOKRISTALLAKH I PLENKAKH GERMANIYA I KREMNIYA),

DTIC Science & Technology

It was found that the esters of polystyrene and cinnamic acid , polyvinyl alcohol, and cinnamic acid have high dielectric characteristics that change...Photosensitive acid -resisting emulsions for use in photoengraving of semiconductor parts and semiconductor surfaces were synthesized and tested...organosilicon compounds, cinnamic aldehyde, emulsions based on azo and diazo compounds and polymeric polyesters--were tested. The photoengraving method

Ultra-High Pressure Homogenization improves oxidative stability and interfacial properties of soy protein isolate-stabilized emulsions.

PubMed

Fernandez-Avila, C; Trujillo, A J

2016-10-15

Ultra-High Pressure Homogenization (100-300MPa) has great potential for technological, microbiological and nutritional aspects of fluid processing. Its effect on the oxidative stability and interfacial properties of oil-in-water emulsions prepared with 4% (w/v) of soy protein isolate and soybean oil (10 and 20%, v/v) were studied and compared to emulsions treated by conventional homogenization (15MPa). Emulsions were characterized by particle size, emulsifying activity index, surface protein concentration at the interface and by transmission electron microscopy. Primary and secondary lipid oxidation products were evaluated in emulsions upon storage. Emulsions with 20% oil treated at 100 and 200MPa exhibited the most oxidative stability due to higher amount of oil and protein surface load at the interface. This manuscript addresses the improvement in oxidative stability in emulsions treated by UHPH when compared to conventional emulsions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Emulsion based cast booster - a priming system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, R.N.; Mishra, A.K.

2005-07-01

This paper explores the potential of emulsion based cast booster to be used as primer to initiate bulk delivered emulsion explosives used in mines. An attempt has been made for comparative study between conventional cast booster and emulsion based cast booster in terms of the initiation process developed and their capability to develop and maintain the stable detonation process in the column explosives. The study has been conducted using a continuous velocity of detonation (VOD) measuring instrument. During this study three blasts have been monitored. In each blast two holes have been selected for study, the first hole being initiatedmore » with conventional cast booster while the other one with emulsion based cast booster. The findings of the study advocates that emulsion based cast booster is capable of efficient priming of bulk delivered column explosive with stable detonation process in the column. Further, the booster had advantages over the conventional PETN/TNT based cast booster. 5 refs., 2 figs., 1 tab., 1 photo.« less

Antibiotic-conjugated polyacrylate nanoparticles: new opportunities for development of anti-MRSA agents.

PubMed

Turos, Edward; Shim, Jeung-Yeop; Wang, Yang; Greenhalgh, Kerriann; Reddy, G Suresh Kumar; Dickey, Sonja; Lim, Daniel V

2007-01-01

This report describes the preparation of polyacrylate nanoparticles in which an N-thiolated beta-lactam antibiotic is covalently conjugated onto the polymer framework. These nanoparticles are formed in water by emulsion polymerization of an acrylated antibiotic pre-dissolved in a liquid acrylate monomer (or mixture of co-monomers) in the presence of sodium dodecyl sulfate as a surfactant and potassium persulfate as a radical initiator. Dynamic light scattering analysis and electron microscopy images of these emulsions show that the nanoparticles are approximately 40 nm in diameter. The emulsions have potent in vitro antibacterial properties against methicillin-resistant Staphylococcus aureus and have improved bioactivity relative to the non-polymerized form of the antibiotic. A unique feature of this methodology is the ability to incorporate water-insoluble drugs directly into the nanoparticle framework without the need for post-synthetic modification. Additionally, the antibiotic properties of the nanoparticles can be modulated by changing the length or location of the acrylate linker on the drug monomer.

Structure- and oil type-based efficacy of emulsion adjuvants.

PubMed

Jansen, Theo; Hofmans, Marij P M; Theelen, Marc J G; Manders, Frans; Schijns, Virgil E J C

2006-06-29

Oil-based emulsions are well-known immunopotentiators for inactivated, "killed" vaccines. We addressed the relationship between emulsion structure and levels of in vivo antibody formation to inactivated New Castle Disease virus (NDV) and Infectious Bronchitis virus (IBV) as antigens in 3-week-old chickens. The use of a polymeric emulsifier allowed for direct comparison of three types of emulsions, water-in-oil (W/O), oil-in-water (O/W) and W/O-in-water (W/O/W), while maintaining an identical content of components for each vehicle. They were prepared with either non-metabolizable, mineral oil or metabolizable, Miglyol 840. In addition, we assessed the inherent release capacity of each emulsion variant in vitro. Remarkably, we noted that W/O-type emulsions induced the best immune responses, while they released no antigen during 3 weeks. In general, mineral oil vaccines showed superior efficacy compared to Miglyol 840-based vaccines.

Thiolated alkyl-modified carbomers: Novel excipients for mucoadhesive emulsions.

PubMed

Bonengel, Sonja; Hauptstein, Sabine; Leonaviciute, Gintare; Griessinger, Julia; Bernkop-Schnürch, Andreas

2015-07-30

The aim of this study was the design and evaluation of mucoadhesive emulsifying polymeric excipients. Three thiol bearing ligands with increasing pKa values of their sulfhydryl group, namely 4-aminothiophenol (pKa=6.86), l-cysteine (pKa=8.4) and d/l-homocysteine (pKa=10.0) were coupled to the polymeric backbone of alkyl-modified carbomer (PA1030). Resulting conjugates displayed 818.5μmol 4-aminothiophenol, 698.5μmol cysteine and 651.5μmol homocysteine per gram polymer and were evaluated regarding the reactivity of thiol groups, emulsifying and mucoadhesive properties. In general, the synthesized conjugates showed a pH dependent reactivity, whereby the fastest oxidation occurred in PA1030-cysteine, as almost no free thiol groups could be detected after 120min. Emulsification of medium chain triglycerides was feasible with all synthesized conjugates leading to oil-in-water-emulsions. Emulsions with PA1030-cysteine displayed the highest stability and the smallest droplet size among the tested formulations. Oxidation and consequently cross-linking of the thiomers prior to the emulsification process led to an overall decreased emulsion stability. Evaluating mucosal residence time of thiomer emulsions on porcine buccal mucosa, a 9.2-fold higher amount of formulation based on PA1030-cysteine remained on the mucosal tissue within 3h compared to the unmodified polymer. According to these results, the highest reactive ligand l-cysteine seems to be most promising in order to obtain thiolated polymers for the preparation of mucoadhesive o/w-emulsions. Copyright © 2015 Elsevier B.V. All rights reserved.

The Effect of Surfactant and Compatibilizer on Inorganic Loading and Properties of PPO-based EPMM Membranes

NASA Astrophysics Data System (ADS)

Bissadi, Golnaz

Hybrid membranes represent a promising alternative to the limitations of organic and inorganic materials for high productivity and selectivity gas separation membranes. In this study, the previously developed concept of emulsion-polymerized mixed matrix (EPMM) membranes was further advanced by investigating the effects of surfactant and compatibilizer on inorganic loading in poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)-based EPMM membranes, in which inorganic part of the membranes originated from tetraethylorthosilicate (TEOS). The polymerization of TEOS, which consists of hydrolysis of TEOS and condensation of the hydrolyzed TEOS, was carried out as (i) one- and (ii) two-step processes. In the one-step process, the hydrolysis and condensation take place in the same environment of a weak acid provided by the aqueous solution of aluminum hydroxonitrate and sodium carbonate. In the two-step process, the hydrolysis takes place in the environment of a strong acid (solution of hydrochloric acid), whereas the condensation takes place in weak base environment obtained by adding excess of the ammonium hydroxide solution to the acidic solution of the hydrolyzed TEOS. For both one- and two-step processes, the emulsion polymerization of TEOS was carried out in two types of emulsions made of (i) pure trichloroethylene (TCE) solvent, and (ii) 10 w/v% solution of PPO in TCE, using different combinations of the compatibilizer (ethanol) and the surfactant (n-octanol). The experiments with pure TCE, which are referred to as a gravimetric powder method (GPM) allowed assessing the effect of different experimental parameters on the conversion of TEOS. The GPM tests also provided a guide for the synthesis of casting emulsions containing PPO, from which the EPMM membranes were prepared using a spin coating technique. The synthesized EPMM membranes were characterized using 29Si nuclear magnetic resonance (29Si NMR), differential scanning calorimetry (DSC), inductively coupled plasma mass spectrometry (ICP-MS), and gas permeation measurements carried out in a constant pressure (CP) system. The 29Si NMR analysis verified polymerization of TEOS in the emulsions made of pure TCE, and the PPO solution in TCE. The conversions of TEOS in the two-step process in the two types of emulsions were very close to each other. In the case of the one-step process, the conversions in the TCE emulsion were significantly greater than those in the emulsion of the PPO solution in TCE. Consequently, the conversions of TEOS in the EPMM membranes made in the two-step process were greater than those in the EPMM membranes made in the one-step process. The latter ranged between 10 - 20%, while the highest conversion in the two-step process was 74% in the presence of pure compatibilizer with no surfactant. Despite greater conversions and hence the greater inorganic loadings, the EPMM membranes prepared in the two-step process had glass transition temperatures (Tg) only slightly greater than the reference PPO membranes. In contrast, despite relatively low inorganic loadings, the EPMM membranes prepared in the one-step process had Tgs markedly greater than PPO, and showed the expected trend of an increase in Tg with the inorganic loading. These results indicate that in the case of the one-step process the polymerized TEOS was well integrated with the PPO chains and the interactions between the two phases lead to high Tgs. On the other hand, this was not the case for the EPMM membranes prepared in the two-step process, suggesting possible phase separation between the polymerized TEOS and the organic phase. The latter was confirmed by detecting no selectivity in the EPMM membranes prepared by the two-step process. In contrast, the EPMM membranes prepared in the one-step process in the presence of the compatibilizer and no surfactant showed 50% greater O2 permeability coefficient and a slightly greater O2/N2 permeability ratio compared to the reference PPO membranes.

A Robust Oil-in-Oil Emulsion for the Nonaqueous Encapsulation of Hydrophilic Payloads.

PubMed

Lu, Xiaocun; Katz, Joshua S; Schmitt, Adam K; Moore, Jeffrey S

2018-03-14

Compartmentalized structures widely exist in cellular systems (organelles) and perform essential functions in smart composite materials (microcapsules, vasculatures, and micelles) to provide localized functionality and enhance materials' compatibility. An entirely water-free compartmentalization system is of significant value to the materials community as nonaqueous conditions are critical to packaging microcapsules with water-free hydrophilic payloads while avoiding energy-intensive drying steps. Few nonaqueous encapsulation techniques are known, especially when considering just the scalable processes that operate in batch mode. Herein, we report a robust oil-in-oil Pickering emulsion system that is compatible with nonaqueous interfacial reactions as required for encapsulation of hydrophilic payloads. A major conceptual advance of this work is the notion of the partitioning inhibitor-a chemical agent that greatly reduces the payload's distribution between the emulsion's two phases, thus providing appropriate conditions for emulsion-templated interfacial polymerization. As a specific example, an immiscible hydrocarbon-amine pair of liquids is emulsified by the incorporation of guanidinium chloride (GuHCl) as a partitioning inhibitor into the dispersed phase. Polyisobutylene (PIB) is added into the continuous phase as a viscosity modifier for suitable modification of interfacial polymerization kinetics. The combination of GuHCl and PIB is necessary to yield a robust emulsion with stable morphology for 3 weeks. Shell wall formation was accomplished by interfacial polymerization of isocyanates delivered through the continuous phase and polyamines from the droplet core. Diethylenetriamine (DETA)-loaded microcapsules were isolated in good yield, exhibiting high thermal and chemical stabilities with extended shelf-lives even when dispersed into a reactive epoxy resin. The polyamine phase is compatible with a variety of basic and hydrophilic actives, suggesting that this encapsulation technology is applicable to other hydrophilic payloads such as polyols, aromatic amines, and aromatic heterocyclic bases. Such payloads are important for the development of extended pot or shelf life systems and responsive coatings that report, protect, modify, and heal themselves without intervention.

Covalent bonding of polycations to small polymeric particles

NASA Technical Reports Server (NTRS)

Rembaum, A.

1975-01-01

Process produces small spherical polymeric particles which have polycations bound to them. In emulsion form, particles present large positively charged surface which is available to absorb polyanions. This properly can be used in removing heparin from blood or bile acids from the digestive tract. Other anions, such as DNA and RNA, can also be removed from aqueous solutions.

Protein specific polymeric immunomicrospheres

NASA Technical Reports Server (NTRS)

Yen, Shiao-Ping S. (Inventor); Dreyer, William J. (Inventor); Rembaum, Alan (Inventor)

1980-01-01

Small, round, bio-compatible microspheres capable of covalently bonding proteins and having a uniform diameter below about 3500 A are prepared by substantially instantaneously initiating polymerization of an aqueous emulsion containing no more than 35% total monomer including an acrylic monomer substituted with a covalently bondable group such as hydroxyl, amino or carboxyl and a minor amount of a cross-linking agent.

Highly temperature responsive core-shell magnetic particles: synthesis, characterization and colloidal properties.

PubMed

Rahman, Md Mahbubor; Chehimi, Mohamed M; Fessi, Hatem; Elaissari, Abdelhamid

2011-08-15

Temperature responsive magnetic polymer submicron particles were prepared by two step seed emulsion polymerization process. First, magnetic seed polymer particles were obtained by emulsion polymerization of styrene using potassium persulfate (KPS) as an initiator and divinylbenzne (DVB) as a cross-linker in the presence of oil-in-water magnetic emulsion (organic ferrofluid droplets). Thereafter, DVB cross-linked magnetic polymer particles were used as seed in the precipitation polymerization of N-isopropylacrylamide (NIPAM) to induce thermosensitive PNIPAM shell onto the hydrophobic polymer surface of the cross-linked magnetic polymer particles. To impart cationic functional groups in the thermosensitive PNIPAM backbone, the functional monomer aminoethylmethacrylate hydrochloride (AEMH) was used to polymerize with NIPAM while N,N'-methylenebisacrylamide (MBA) and 2, 2'-azobis (2-methylpropionamidine) dihydrochloride (V-50) were used as a cross-linker and as an initiator respectively. The effect of seed to monomer (w/w) ratio along with seed nature on the final particle morphology was investigated. Dynamic light scattering (DLS) results demonstrated particles swelling at below volume phase transition temperature (VPTT) and deswelling above the VPTT. The perfect core (magnetic) shell (polymer) structure of the particles prepared was confirmed by Transmission Electron Microscopy (TEM). The chemical composition of the particles were determined by thermogravimetric analysis (TGA). The effect of temperature, pH, ionic strength on the colloidal properties such as size and zeta potential of the micron sized thermo-sensitive magnetic particles were also studied. In addition, a short mechanistic discussion on the formation of core-shell morphology of magnetic polymer particles has also been discussed. Copyright © 2011 Elsevier Inc. All rights reserved.

A flexible, robust and antifouling asymmetric membrane based on ultra-long ceramic/polymeric fibers for high-efficiency separation of oil/water emulsions.

PubMed

Wang, Kui; Yiming, Wubulikasimu; Saththasivam, Jayaprakash; Liu, Zhaoyang

2017-07-06

Polymeric and ceramic asymmetric membranes have dominated commercial membranes for water treatment. However, polymeric membranes are prone to becoming fouled, while ceramic membranes are mechanically fragile. Here, we report a novel concept to develop asymmetric membranes based on ultra-long ceramic/polymeric fibers, with the combined merits of good mechanical stability, excellent fouling resistance and high oil/water selectivity, in order to meet the stringent requirements for practical oil/water separation. The ultra-long dimensions of ceramic nanofibers/polymeric microfibers endow this novel membrane with mechanical flexibility and robustness, due to the integrated and intertwined structure. This membrane is capable of separating oil/water emulsions with high oil-separation efficiency (99.9%), thanks to its nanoporous selective layer made of ceramic nanofibers. Further, this membrane also displays superior antifouling properties due to its underwater superoleophobicity and ultra-low oil adhesion of the ceramic-based selective layer. This membrane exhibits high water permeation flux (6.8 × 10 4 L m -2 h -1 bar -1 ) at low operation pressures, which is attributed to its 3-dimensional (3D) interconnected fiber-based structure throughout the membrane. In addition, the facile fabrication process and inexpensive materials required for this membrane suggest its significant potential for industrial applications.

Synthesis of High Molecular Weight Poly(glycerol monomethacrylate) via RAFT Emulsion Polymerization of Isopropylideneglycerol Methacrylate

PubMed Central

2018-01-01

High molecular weight water-soluble polymers are widely used as flocculants or thickeners. However, synthesis of such polymers via solution polymerization invariably results in highly viscous fluids, which makes subsequent processing somewhat problematic. Alternatively, such polymers can be prepared as colloidal dispersions; in principle, this is advantageous because the particulate nature of the polymer chains ensures a much lower fluid viscosity. Herein we exemplify the latter approach by reporting the convenient one-pot synthesis of high molecular weight poly(glycerol monomethacrylate) (PGMA) via the reversible addition–fragmentation chain transfer (RAFT) aqueous emulsion polymerization of a water-immiscible protected monomer precursor, isopropylideneglycerol methacrylate (IPGMA) at 70 °C, using a water-soluble poly(glycerol monomethacrylate) (PGMA) chain transfer agent as a steric stabilizer. This formulation produces a low-viscosity aqueous dispersion of PGMA–PIPGMA diblock copolymer nanoparticles at 20% solids. Subsequent acid deprotection of the hydrophobic core-forming PIPGMA block leads to particle dissolution and affords a viscous aqueous solution comprising high molecular weight PGMA homopolymer chains with a relatively narrow molecular weight distribution. Moreover, it is shown that this latex precursor route offers an important advantage compared to the RAFT aqueous solution polymerization of glycerol monomethacrylate since it provides a significantly faster rate of polymerization (and hence higher monomer conversion) under comparable conditions. PMID:29805184

Preparation of hybrid thiol-acrylate emulsion-templated porous polymers by interfacial copolymerization of high internal phase emulsions.

PubMed

Langford, Caitlin R; Johnson, David W; Cameron, Neil R

2015-05-01

Emulsion-templated highly porous polymers (polyHIPEs), containing distinct regions differing in composition, morphology, and/or properties, are prepared by the simultaneous polymerization of two high internal phase emulsions (HIPEs) contained within the same mould. The HIPEs are placed together in the mould and subjected to thiol-acrylate photopolymerization. The resulting polyHIPE material is found to contain two distinct semicircular regions, reflecting the composition of each HIPE. The original interface between the two emulsions becomes a copolymerized band between 100 and 300 μm wide, which is found to be mechanically robust. The separate polyHIPE layers are distinguished from one another by their differing average void diameter, chemical composition, and extent of contraction upon drying. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methods for purifying and detoxifying sodium dodecyl sulfate-stabilized polyacrylate nanoparticles.

PubMed

Garay-Jimenez, Julio C; Young, Ashley; Gergeres, Danielle; Greenhalgh, Kerriann; Turos, Edward

2008-06-01

Recent research in our laboratory has centered on studies of polyacrylate and polyacrylamide nanoparticle emulsions for use in antibiotic delivery. Our goal is to develop these nanoparticle emulsions for treatment of life-threatening bacterial infections such as those caused by methicillin-resistant Staphylococcus aureus. For this intended application it is necessary to ensure that the biological activity of the emulsion is due only to the drug attached to the polymeric chain and not to any extraneous components. To investigate this we evaluated cytotoxicity and microbiological activity of the nanoparticle emulsions before and after purification by centrifugation, dialysis, and gel filtration. Depending on the amount of surfactant used, all or most of the microbial and cellular toxicity can be removed by a simple purification procedure.

Waterborne Polymeric Films.

DTIC Science & Technology

1979-12-01

resin types: 1) acrylic latex, 2) acrylic solution polymer, 3) epoxy emulsions, 4) polyurethane, 5) butadiene elastomeric latex, 6) polyester/ alkyd , 7...emulsions and the class of polyester/ alkyd resins were evaluated only as network, crosslinked films. -53- j z I, ACRYLIC SOLUTIONLATEX URE THANE ACRYLIC ...amount of "plasticizing" monomer such as ethyl acrylate . 2.3.1.3 Aqueous Polyester Alkyd Resins As indicated in section 2.2.7 of this report,

Sulfonated amphiphilic block copolymers : synthesis, self-assembly in water, and application as stabilizer in emulsion polymerization

Treesearch

Jiguang Zhang; Matthew R. Dubay; Carl J. Houtman; Steven J. Severtson

2009-01-01

Described is the synthesis of diblock copolymers generated via sequential atom transfer radical polymerization (ATRP) of poly(n-butyl acrylate) (PnBA) followed by chain augmentation with either sulfonated poly(2-hydroxyethyl methacrylate) (PHEMA) or poly(2-hydroxyethyl acrylate) (PHEA) blocks. ATRP of PHEMA or PHEA from PnBA macroinitiator was conducted in acetone/...

Particulate Coacervation of Associative Polymer Brushes-Grafted Nanoparticles To Produce Structurally Stable Pickering Emulsions.

PubMed

Yang, Taeseung; Choi, Sang Koo; Park, Daehwan; Lee, Yea Ram; Chung, Chan Bok; Kim, Jin Woong

2016-12-20

This study introduces a new type of associative nanoparticle (ANP) that provides controlled chain-to-chain attraction with an associative polymer rheology modifier (APRM) to produce highly stable Pickering emulsions. The ANPs were synthesized by grafting hydrophobically modified hygroscopic zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine-co-stearyl methacrylate) brushes onto 20 nm sized silica NPs via surface-mediated living radical polymerization. The ANP-stabilized Pickering emulsions show significant viscosity enhancement in the presence of the APRM. This indicates that the ANPs act as particulate concentration agents at the interface owing to their hydrophobic association with the APRM in the aqueous phase, which leads to the generation of an ANP-mediated complex colloidal film. Consequently, the described ANP-reinforced Pickering emulsion system exhibits improved resistance to pH and salinity changes. This coacervation approach is advantageous because the complex colloidal layer at the interface provides the emulsion drops with a mechanically robust barrier, thus guaranteeing the improved Pickering emulsion stability against harsh environmental factors.

Specially Treated Aramid Fiber Stabilized Gel-Emulsions: Preparation of Porous Polymeric Monoliths and Highly Efficient Removing of Airborne HCHO.

PubMed

Liu, Jianfei; Chen, Xiangli; Wang, Pei; Fu, Xuwei; Liu, Kaiqiang; Fang, Yu

2017-08-01

Porous polymeric monoliths with densities as low as ≈0.060 g cm -3 are prepared in a gel-emulsion template way, of which the stabilizer employed is a newly discovered acidified aramid fiber that is so efficient that 0.05% (w/v, accounts for continuous phase) is enough to gel the system. The porous monoliths as obtained can be dried at ambient conditions, avoiding energy-consuming processes. Importantly, the monoliths show selective adsorption to HCHO, and the corresponding adsorption capacity (M6) is ≈2700 mg g -1 , the best result that is reported until now. More importantly, the monoliths can be reused after drying. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of ultrahigh-molecular weight cationic polyacrylamide using frit-inlet asymmetrical flow field-flow fractionation and multi-angle light scattering.

PubMed

Woo, Sohee; Lee, Ju Yong; Choi, Woonjin; Moon, Myeong Hee

2016-01-15

In this study, frit inlet asymmetrical flow field-flow fractionation (FlFFF) with multi-angle light scattering (MALS) and differential refractive index (DRI) detection is utilized for size separation, determination of molecular weight (MW), and conformation of ultrahigh-MW (10(7)-10(9) g/mol) cationic polyacrylamides (C-PAMs), a class of water-soluble copolymers based on acrylamide and vinyl-type comonomers with quaternary ammonium cations that are widely used in wastewater treatment and in paper industries. Linear and branched C-PAM copolymers prepared in two different polymerization methods (solution and emulsion) from varying amounts of crosslinking agent and initiator were size fractionated by FlFFF with field-programming. It was found experimentally that the linear copolymers from both polymerization methods were less than 10(8) g/mol in MW with compact, nearly spherical structures, while the branched C-PAM copolymers from the emulsion polymerization showed a significant increase in average MW up to ∼ 10(9)g/mol, which was about 20-fold greater than those from the solution method, and the branched copolymers had more compact or shrunken conformations. While both linear and branched copolymers less than 10(8) g/mol MW were well resolved in an increasing order of MW (normal mode), it was noted that branched copolymers prepared through emulsion polymerization exhibited significantly larger MWs of 10(8-)10(9) g/mol and eluted in the steric/hyperlayer mode, in which the elution order is reversed in an extreme run condition (strong initial field strength followed by a fast field decay during programming). Copyright © 2015 Elsevier B.V. All rights reserved.

Preparation of poly(BMA-co-MMA) particles by soap-free emulsion polymerization and its optical properties as photonic crystals.

PubMed

Lee, Ki-Chang; Choo, Hun-Seung

2014-11-01

Narrowly dispersed poly(BMA-co-MMA) and PBMA latices with particle diameters ranging within 216-435 nm were synthesized successfully by surfactant-free emulsion polymerization with KPS and AIBA. The average particle diameter and particle size distribution, average molecular weight and its distribution, glass transition temperature, reflectance spectra in visible wavelength, and refractive indices for the respective poly(BMA-co-MMA) latices and their photonic crystals were systematically investigated in terms of BMA/MMA ratio, BMA content, polymerization temperature, and DVB effect. The rate of polymerization increased with increasing MMA concentration in BMA/MMA ratio. The particle diameter increased with BMA concentration in BMA/MMA ratio. The molecular weight increased with BMA concentration in BMA/MMA ratio and monomer concentration. The drying of the latices offered self-assembled shiny colloidal crystal films showing the characteristic structural colors in visible wavelength. All the poly(BMA-co-MMA) latices prepared in the study were fallen within the range of photonic grade microspheres. The reflectance measurement on the colloidal photonic crystals having different particle diameters clearly exhibited narrow stopbands. The reflection maxima (λ(max)) measured in this study were well close to the λ(max) calculated, derived from the Bragg's equation. The refractive indices of poly(BMA-co-MMA) photonic crystals were found to be almost same as the theoretical values and increased proportionally from 1.50 to 1.57 with BMA content in BMA/MMA ratios. It was, thus, found that the optical reflectance properties of the poly(BMA-co-MMA) colloidal photonic crystals can be controlled easily by adjusting the reaction conditions and BMA/MMA ratio in soap-free emulsion copolymerization of BMA and MMA.

Methods for Purifying and Detoxifying Sodium Dodecyl Sulfate-Stabilized Polyacrylate Nanoparticles

PubMed Central

Garay-Jimenez, Julio C.; Young, Ashley; Gergeres, Danielle; Greenhalgh, Kerriann; Turos, Edward

2008-01-01

Recent research in our laboratory has centered on studies of polyacrylate and polyacrylamide nanoparticle emulsions for use in antibiotic delivery. Our goal is to develop these nanoparticle emulsions for treatment of life-threatening bacterial infections such as those caused by methicillin-resistant Staphylococcus aureus (MRSA). For this intended application, it is necessary to ensure that the biological activity of the emulsion is due only to the drug attached to the polymeric chain, rather than to any extraneous components. To investigate this, we evaluated cytotoxicity and microbiological activity of the nanoparticle emulsions before and after purification by centrifugation, dialysis, and gel filtration. Depending on the amount of surfactant used, all or most of the microbial and cellular toxicity can be removed by a simple purification procedure. PMID:18472305

Superparamagnetic polymer emulsion particles from a soap-free seeded emulsion polymerization and their application for lipase immobilization.

PubMed

Cui, Yanjun; Chen, Xia; Li, Yanfeng; Liu, Xiao; Lei, Lin; Zhang, Yakui; Qian, Jiayu

2014-01-01

Using emulsion copolymer of styrene (St), glycidyl methacrylate (GMA) and 2-hydroxyethyl methacrylate (HEMA) as seed latexes, the superparamagnetic polymer emulsion particles were prepared by seeded emulsion copolymerization of butyl methacrylate (BMA), vinyl acetate (VAc) and ethylene glycol dimethacrylate in the presence of the seed latexes and superparamagnetic Fe3O4/SiOx nanoparticles (or Fe3O4-APTS nanoparticles) through a two-step process, without addition of any emulsifier. The magnetic emulsion particles named P(St-GMA-HEMA)/P(BMA-VAc) were characterized by transmission electron microscope and vibrating sample magnetometry. The results showed that the magnetic emulsion particles held a structure with a thinner shell (around 100 nm) and a bigger cavity (around 200 nm), and possessed a certain level of magnetic response. The resulting magnetic emulsion particles were employed in the immobilization of lipase by two strategies to immobilized lipase onto the resulting magnetic composites directly (S-1) or using glutaraldehyde as a coupling agent (S-2), thus, experimental data showed that the thermal stability and reusability of immobilized lipase based on S-2 were higher than that of S-1.

Synthesis and characterization of novel polyacid-stabilized latexes.

PubMed

Yang, Pengcheng; Armes, S P

2012-09-18

A series of novel polyacid macromonomers based on 2-hydroxypropyl methacrylate (HPMA) were prepared by atom transfer radical polymerization (ATRP) via a two-step route. First, a range of well-defined PHPMA homopolymer precursors were synthesized by ATRP using a tertiary amine-functionalized initiator, 2-(dimethylamino)ethyl-2-bromoisobutyrylamide, and a CuCl/2, 2'-bipyridine (bpy) catalyst in alcoholic media at 50 °C. ATRP polymerizations were relatively slow and poorly controlled in pure isopropanol (IPA), especially when targeting higher degrees of polymerization (DP > 30). Improved control was achieved by addition of water: low polydispersity (M(w)/M(n) < 1.25) PHPMA homopolymers of DP = 30, 40, 50, 60, or 70 were successfully prepared using a 9:1 w/w % IPA/water mixture at 50 °C. These PHPMA homopolymer precursors were then derivatized to produce the corresponding poly(2-(succinyloxy)propyl methacrylate) (PSPMA) macromonomers by quaternizing the tertiary amine end-group with excess 4-vinylbenzyl chloride, followed by esterification of the pendent hydroxyl groups using excess succinic anhydride at 20 °C. These polyacid macromonomers were evaluated as reactive steric stabilizers for polystyrene latex synthesis under either aqueous emulsion polymerization or alcoholic dispersion polymerization conditions. Near-monodisperse polystyrene latexes were obtained via aqueous emulsion polymerization using 10 wt % PSPMA macromonomer (with respect to styrene monomer) with various initiators as evidenced by scanning electron microscopy, disk centrifuge photosedimentometry and light scattering studies. PSPMA macromomer concentrations as low as 1.0 wt % also produced near-monodisperse latexes, suggesting that these PSPMA macromonomers are highly effective stabilizers. Alcoholic dispersion polymerization of styrene conducted in various ethanol/water mixtures with 10 wt % PSPMA(50) macromonomer produced relatively large near-monodisperse latexes. Increasing the water content in such formulations led to smaller latexes, as expected. Control experiments conducted with 10 wt % PSPMA(50) homopolymer produced relatively large polydisperse latexes via emulsion polymerization and only macroscopic precipitates via alcoholic dispersion polymerization. Thus the terminal styrene group on the macromonomer chains is essential for the formation of well-defined latexes. FT-IR spectroscopy indicated that these latexes contained PSPMA macromonomer, whereas (1)H NMR spectroscopy studies of dissolved latexes allowed stabilizer contents to be determined. Aqueous electrophoresis and X-ray photoelectron spectroscopy studies confirmed that the PSPMA macromonomer chains were located at the latex surface, as expected. Finally, these polyacid-stabilized polystyrene latexes exhibited excellent freeze-thaw stability and remained colloidally stable in the presence of electrolyte.

Rapid crystallization and morphological adjustment of zeolite ZSM-5 in nonionic emulsions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang Ying, E-mail: yingzh1977@163.co; Jin Chao; Research Institute of Petroleum Processing, Beijing 100083

2011-01-15

Zeolite ZSM-5 was synthesized for the first time in a nonionic emulsion composed of polyoxyethylated alkylphenol, butanol, cyclohexane and tetraethylammonium hydroxide (TEAOH)-containing zeolite synthesis mixture. The crystallization kinetics in the emulsion was investigated and the ZSM-5 product was characterized in detail by XRD, SEM, FT-IR, TG, N{sub 2} adsorption and CHN analysis techniques. Compared with the conventionally hydrothermal synthesis with the same structure directing agent TEAOH, the emulsion system allows rapid crystallization of ZSM-5. The ZSM-5 product exhibits unusual agglomerated structure and possesses larger specific surface area. The FT-IR, TG results plus CHN analysis show the encapsulation of a tracemore » of emulsion components in the emulsion ZSM-5. Control experiments show the emulsion system exerts the crystallization induction and morphological adjustment effects mainly during the aging period. The effects are tentatively attributed to the confined space domains, surfactant-water interaction as well as surfactant-growing crystals interaction existing in the emulsion. -- Graphical abstract: The nonionic emulsion synthesis allows rapid crystallization and morphological adjustment of zeolite ZSM-5 compared with the conventional hydrothermal synthesis. Display Omitted« less

The Morphology of Emulsion Polymerized Latex Particles

DOE R&D Accomplishments Database

Wignall, G. D.; Ramakrishnan, V. R.; Linne, M. A.; Klein, A.; Sperling, L. H.; Wai, M. P.; Gelman, R. A.; Fatica, M. G.; Hoerl, R. H.; Fisher, L. W.

1987-11-01

Under monomer starved feed conditions, emulsion polymerization of perdeuterated methyl methacrylate and styrene in the presence of preformed polymethylmethacrylate latexes resulted in particles with a core-shell morphology, as determined by small-angle neutron scattering (SANS) analysis for a hollow sphere. The locus of polymerization of the added deuterated monomer is therefore at the particle surface. In similar measurements a statistical copolymer of styrene and methyl methacrylate was used as seed particles for further polymerization of trideuteromethyl methacrylate. The resulting polymer latex was again shown to have a core-shell morphological structure as determined by SANS. SANS experiments were also undertaken on polystyrene latexes polymerized by equilibrium swelling methods, with deuterated polymer forming the first or second step. The experiments covered a molecular weight range of 6 x 10{sup 4} 10{sup 6} the molecular weights are consistent with the experimental errors, indicating that the deuterium labeled molecules are randomly distributed in the latex. These results led to the finding that the polymer chains were constrained in the latex particles by factors of 2 to 4 from the relaxed coil dimensions. For M < 10{sup 6} g/mol SANS gave zero angle scattering intensities much higher than expected on the basis of a random distribution of labeled molecules. Several models were examined, including the possible development of core-shell structures at lower molecular weights.

Lipid transfer in oil-in-water isasome emulsions: influence of arrested dynamics of the emulsion droplets entrapped in a hydrogel.

PubMed

Iglesias, Guillermo Ramón; Pirolt, Franz; Sadeghpour, Amin; Tomšič, Matija; Glatter, Otto

2013-12-17

The transfer kinetics of lipids between internally self-assembled droplets of O/W emulsions is studied. The droplets (isasomes) consist of various liquid-crystalline phases or W/O microemulsions stabilized by a polymeric stabilizer F127. The various internal phases were identified by the relative peak positions in the small-angle X-ray scattering (SAXS) curves. An arrested system composed of isasomes embedded in a gel matrix actually provides an additional possibility to control these systems in terms of the release of various host molecules. These experiments have been applied to examine the kinetics of the internal phase reorganization imposed by the lipids' release and uptake by the droplets embedded in a κ-carrageenan (KC) hydrogel network. Increasing the concentration of the gelling agent slows down the transfer from one droplet to the other through the aqueous phase. We examined the region where the free diffusion is stopped. i.e., the point where the system changes from the ergodic to the nonergodic state and the kinetics is essentially slowed down. This effect can be balanced by the addition of small amounts of free polymeric stabilizer, which speeds up the kinetics. This is even possible in the case of highly arrested dynamics of the emulsion droplets, as found for the highest KC hydrogel concentrations forming nonergodic systems.

Arrays of size and distance controlled platinum nanoparticles fabricated by a colloidal method

NASA Astrophysics Data System (ADS)

Manzke, Achim; Vogel, Nicolas; Weiss, Clemens K.; Ziener, Ulrich; Plettl, Alfred; Landfester, Katharina; Ziemann, Paul

2011-06-01

Based on emulsion polymerization in the presence of a Pt complex, polystyrene (PS) particles were prepared exhibiting a well defined average diameter with narrow size-distribution. Furthermore, the colloids contain a controlled concentration of the Pt precursor complex. Optimized coating of Si substrates with such colloids leads to extended areas of hexagonally ordered close-packed PS particles. Subsequent application of plasma etching and annealing steps allows complete removal of the PS carriers and in parallel nucleation and growth of Pt nanoparticles (NPs) which are located at the original center of the PS colloids. In this way, hexagonally arranged spherical Pt NPs are obtained with controlled size and interparticle distances demonstrating variability and precision with so far unknown parameter scalability. This control is demonstrated by the fabrication of Pt NP arrays at a fixed particle distance of 185 nm while systematically varying the diameters between 8 and 15 nm. Further progress could be achieved by seeded emulsion polymerization. Here, Pt loaded PS colloids of 130 nm were used as seeds for a subsequent additional emulsion polymerization, systematically enlarging the diameter of the PS particles. Applying the plasma and annealing steps as above, in this way hexagonally ordered arrays of 9 nm Pt NPs could be obtained at distances up to 260 nm. To demonstrate their stability, such Pt particles were used as etching masks during reactive ion etching thereby transferring their hexagonal pattern into the Si substrate resulting in corresponding arrays of nanopillars.Based on emulsion polymerization in the presence of a Pt complex, polystyrene (PS) particles were prepared exhibiting a well defined average diameter with narrow size-distribution. Furthermore, the colloids contain a controlled concentration of the Pt precursor complex. Optimized coating of Si substrates with such colloids leads to extended areas of hexagonally ordered close-packed PS particles. Subsequent application of plasma etching and annealing steps allows complete removal of the PS carriers and in parallel nucleation and growth of Pt nanoparticles (NPs) which are located at the original center of the PS colloids. In this way, hexagonally arranged spherical Pt NPs are obtained with controlled size and interparticle distances demonstrating variability and precision with so far unknown parameter scalability. This control is demonstrated by the fabrication of Pt NP arrays at a fixed particle distance of 185 nm while systematically varying the diameters between 8 and 15 nm. Further progress could be achieved by seeded emulsion polymerization. Here, Pt loaded PS colloids of 130 nm were used as seeds for a subsequent additional emulsion polymerization, systematically enlarging the diameter of the PS particles. Applying the plasma and annealing steps as above, in this way hexagonally ordered arrays of 9 nm Pt NPs could be obtained at distances up to 260 nm. To demonstrate their stability, such Pt particles were used as etching masks during reactive ion etching thereby transferring their hexagonal pattern into the Si substrate resulting in corresponding arrays of nanopillars. Electronic supplementary information (ESI) available: Detailed description of the experimental part (S1-S4) platinum concentration inside the polymer particles synthesized by a seeded polymerization from the same seed particles measured by ICP-OES (Fig. S1 and S5); SEM image of Pt complex containing PS particles after oxygen plasma treatment (Fig. S2 and S6); effect of hydrofluoric acid treatment on silicon oxide elevation under Pt NPs (Fig. S3 and S6); SEM images demonstrating the variability of Pt NP distance while keeping the diameter constant (Fig. S4 and S8); results of experimental determination of Pt content by ICP-OES (Tables S1 and S9); diameter of the particles at different fabrication states (Tables S2 and S10). See DOI: 10.1039/c1nr10169b

Enhancement of thermal and mechanical properties of poly(MMA-co-BA)/Cloisite 30B nanocomposites by ultrasound-assisted in-situ emulsion polymerization.

PubMed

Sharma, Sachin; Kumar Poddar, Maneesh; Moholkar, Vijayanand S

2017-05-01

This study reports synthesis and characterization of poly(MMA-co-BA)/Cloisite 30B (organo-modified montmorillonite clay) nanocomposites by ultrasound-assisted in-situ emulsion polymerization. Copolymers have been synthesized with MMA:BA monomer ratio of 4:1, and varying clay loading (1-5wt% monomer). The poly(MMA-co-BA)/Cloisite 30B nanocomposites have been characterized for their thermal and mechanical properties. Ultrasonically synthesized nanocomposites have been revealed to possess higher thermal degradation resistance and mechanical strength than the nanocomposites synthesized using conventional techniques. These properties, however, show an optimum (or maxima) with clay loading. The maximum values of thermal and mechanical properties of the nanocomposites with optimum clay loading are as follows. Thermal degradation temperatures: T 10% =320°C (4wt%), T 50 =373°C (4wt%), maximum degradation temperature=384°C (4wt%); glass transition temperature=64.8°C (4wt%); tensile strength=20MPa (2wt%), Young's modulus=1.31GPa (2wt%), Percentage elongation=17.5% (1wt%). Enhanced properties of poly(MMA-co-BA)/Cloisite 30B nanocomposites are attributed to effective exfoliation and dispersion of clay nanoparticles in copolymer matrix due to intense micro-convection induced by ultrasound and cavitation. Clay platelets help in effective heat absorption with maximum surface interaction/adhesion that results in increased thermal resistivity of nanocomposites. Hindered motion of the copolymer chains due to clay platelets results in enhancement of tensile strength and Young's modulus of nanocomposite. Rheological (liquid) study of the nanocomposites reveals that nanocomposites have higher yield stress and infinite shear viscosity than neat copolymer. Nonetheless, nanocomposites still display shear thinning behavior - which is typical of the neat copolymer. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation and characterization of Phase change material microcapsules by a core-shell-like emulsion polymerization method

NASA Astrophysics Data System (ADS)

Ding, Li-ming; Pei, Guang-ling

2015-07-01

Phase change material microcapsules (MicroPCMs) were synthesized by a coreshell-like emulsion polymerization method. Styrene and methylacrylic acid copolymer (PS- MAA) was used as a wall material, and paraffin was used as a core material in order to prepare spherical, high resistance and high enthalpy MicroPCMs. Scanning Electron Microscope (SEM), laser particle size analyzer, Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TG) and Differential Scanning Calorimeter (DSC) were employed to characterize the MicroPCMs. The results indicated that the average particle size of MicroPCMs was 42.29 μm, and the content of paraffin within microcapsules was 57.6%. The melting temperature and crystallization temperature were 30.7°C and 25.2°C.The melting enthalpy and crystallization enthalpy were -84.1 J/g and 91.3 J/g, respectively.

Selective separation of lambdacyhalothrin by porous/magnetic molecularly imprinted polymers prepared by Pickering emulsion polymerization.

PubMed

Hang, Hui; Li, Chunxiang; Pan, Jianming; Li, Linzi; Dai, Jiangdong; Dai, Xiaohui; Yu, Ping; Feng, Yonghai

2013-10-01

Porous/magnetic molecularly imprinted polymers (PM-MIPs) were prepared by Pickering emulsion polymerization. The reaction was carried out in an oil/water emulsion using magnetic halloysite nanotubes as the stabilizer instead of a toxic surfactant. In the oil phase, the imprinting process was conducted by radical polymerization of functional and cross-linked monomers, and porogen chloroform generated steam under the high reaction temperature, which resulted in some pores decorated with easily accessible molecular binding sites within the as-made PM-MIPs. The characterization demonstrated that the PM-MIPs were porous and magnetic inorganic-polymer composite microparticles with magnetic sensitivity (M(s) = 0.7448 emu/g), thermal stability (below 473 K) and magnetic stability (over the pH range of 2.0-8.0). The PM-MIPs were used as a sorbent for the selective binding of lambdacyhalothrin (LC) and rapidly separated under an external magnetic field. The Freundlich isotherm model gave a good fit to the experimental data. The adsorption kinetics of the PM-MIPs was well described by pseudo-second-order kinetics, indicating that the chemical process could be the rate-limiting step in the adsorption of LC. The selective recognition experiments exhibited the outstanding selective adsorption effect of the PM-MIPs for target LC. Moreover, the PM-MIPs regeneration without significant loss in adsorption capacity was demonstrated by at least four repeated cycles. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Emulsion-Assisted Polymerization-Induced Hierarchical Self-Assembly of Giant Sea Urchin-like Aggregates in a Large Scale.

PubMed

Xu, Qingsong; Huang, Tong; Li, Shanlong; Li, Ke; Li, Chuanlong; Liu, Yannan; Wang, Yuling; Yu, Chunyang; Zhou, Yongfeng

2018-05-09

Hierarchical solution self-assembly has nowadays become an important biomimetic method to prepare highly complex and multifunctional supramolecular structures. However, despites the great progress, it is still highly challenging to prepare hierarchical self-assemblies in a large scale since the self-assembly processes are generally performed at high dilution. Herein, we report an emulsion-assisted polymerization-induced self-assembly (EAPISA) method with the advantages of in-situ self-assembly process, scalable preparation and facile functionalization to prepare hierarchical multiscale sea urchin-like aggregates (SUAs). It also extends horizons of PISA in monomers and in polymerization method. The obtained SUAs from amphiphilic alternating copolymers represent a novel self-assembled structure with micron-sized rattan ball-like capsule (RBC) acting as the hollow core body and radiating nanotubes tens of micrometers in length as the hollow spines. They can effectively capture model proteins at an ultra-low concentration (≈10 nM) after functionalized with amino groups through click copolymerization. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tunable poly(methacrylic acid-co-acrylamide) nanoparticles through inverse emulsion polymerization.

PubMed

Zhong, Justin X; Clegg, John R; Ander, Eric W; Peppas, Nicholas A

2018-06-01

Environmentally responsive biomaterials have played key roles in the design of biosensors and drug delivery vehicles. Their physical response to external stimuli, such as temperature or pH, can transduce a signal or trigger the release of a drug. In this work, we designed a robust, highly tunable, pH-responsive nanoscale hydrogel system. We present the design and characterization of poly(methacrylic acid-co-acrylamide) hydrogel nanoparticles, crosslinked with methylenebisacrylamide, through inverse emulsion polymerization. The effects of polymerization parameters (i.e., identities and concentrations of monomer and surfactant) and polymer composition (i.e., weight fraction of ionic and crosslinking monomers) on the nanoparticles' bulk and environmentally responsive properties were determined. We generated uniform, spherical nanoparticles which, through modulation of crosslinking, exhibit a volume swelling of 1.77-4.07, relative to the collapsed state in an acidic environment. We believe our system has potential as a base platform for the targeted, injectable delivery of hydrophilic therapeutics. With equal importance, however, we hope that our systematic analysis of the individual impacts of polymerization and purification conditions on nanoparticle composition, morphology, and performance can be used to expedite the development of alternate hydrophilic nanomaterials for a range of biomedical applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1677-1686, 2018. © 2018 Wiley Periodicals, Inc.

Dispersion Polymerization of Polystyrene Particles Using Alcohol as Reaction Medium

NASA Astrophysics Data System (ADS)

Cho, Young-Sang; Shin, Cheol Hwan; Han, Sujin

2016-02-01

In this study, monodisperse polystyrene nanospheres were prepared by dispersion polymerization using alcohol as reaction medium to prepare colloidal clusters of the latex beads. Polyvinylpyrrolidone (PVP) and 2-(methacryloyloxy)ethyltrimethylammonium chloride (MTC) were used as dispersion stabilizer and comonomer, respectively. The particle size could be controlled by adjusting the reactant compositions such as the amount of stabilizer, comonomer, and water in the reactant mixture. The size and monodispersity of the polymeric particles could be also controlled by changing the reaction medium with different alcohols other than ethanol or adjusting the polymerization temperature. The synthesized particles could be self-organized inside water-in-oil emulsion droplets by evaporation-driven self-assembly to produce colloidal clusters of the polymeric nanospheres.

Emulsion Inks for 3D Printing of High Porosity Materials.

PubMed

Sears, Nicholas A; Dhavalikar, Prachi S; Cosgriff-Hernandez, Elizabeth M

2016-08-01

Photocurable emulsion inks for use with solid freeform fabrication (SFF) to generate constructs with hierarchical porosity are presented. A high internal phase emulsion (HIPE) templating technique was utilized to prepare water-in-oil emulsions from a hydrophobic photopolymer, surfactant, and water. These HIPEs displayed strong shear thinning behavior that permitted layer-by-layer deposition into complex shapes and adequately high viscosity at low shear for shape retention after extrusion. Each layer was actively polymerized with an ultraviolet cure-on-dispense (CoD) technique and compositions with sufficient viscosity were able to produce tall, complex scaffolds with an internal lattice structure and microscale porosity. Evaluation of the rheological and cure properties indicated that the viscosity and cure rate both played an important role in print fidelity. These 3D printed polyHIPE constructs benefit from the tunable pore structure of emulsion templated material and the designed architecture of 3D printing. As such, these emulsion inks can be used to create ultra high porosity constructs with complex geometries and internal lattice structures not possible with traditional manufacturing techniques. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of PLGA-Lipid Hybrid Nanoparticles for siRNA Delivery Using the Emulsion Method PLGA-PEG-Lipid Nanoparticles for siRNA Delivery.

PubMed

Wang, Lei; Griffel, Benjamin; Xu, Xiaoyang

2017-01-01

The effective delivery of small interfering RNA (siRNA) to tumor cells remains a challenge for applications in cancer therapy. The development of polymeric nanoparticles with high siRNA loading efficacy has shown great potential for cancer targets. Double emulsion solvent evaporation technique is a useful tool for encapsulation of hydrophilic molecules (e.g., siRNA). Here we describe a versatile platform for siRNA delivery based on PLGA-PEG-cationic lipid nanoparticles by using the double emulsion method. The resulting nanoparticles show high encapsulation efficiency for siRNA (up to 90%) and demonstrate effective downregulation of the target genes in vitro and vivo.

Cold in-place recycling and full-depth recycling with asphalt products (CIR&FDRwAP).

DOT National Transportation Integrated Search

2009-03-01

In the 60s, 70s, and 80s, many Illinois local road agencies successfully used conventional asphalt : emulsions for In-Place Recycling to produce Emulsion-Aggregate-Mixtures (EAMs). In more recent years, these : emulsions have not been ...

A convenient method to prepare emulsified polyacrylate nanoparticles from powders [corrected] for drug delivery applications.

PubMed

Garay-Jimenez, Julio C; Turos, Edward

2011-08-01

We describe a method to obtain purified, polyacrylate nanoparticles in a homogeneous powdered form that can be readily reconstituted in aqueous media for in vivo applications. Polyacrylate-based nanoparticles can be easily prepared by emulsion polymerization using a 7:3 mixture of butyl acrylate and styrene in water containing sodium dodecyl sulfate as a surfactant and potassium persulfate as a water-soluble radical initiator. The resulting emulsions contain nanoparticles measuring 40-50 nm in diameter with uniform morphology, and can be purified by centrifugation and dialysis to remove larger coagulants as well as residual surfactant and monomers associated with toxicity. These purified emulsions can be lyophilized in the presence of maltose (a non-toxic cryoprotectant) to provide a homogeneous dried powder, which can be reconstituted as an emulsion by addition of an aqueous diluent. Dynamic light scattering and microbiological experiments were carried out on the reconstituted nanoparticles. This procedure allows for ready preparation of nanoparticle emulsions for drug delivery applications. Copyright © 2011 Elsevier Ltd. All rights reserved.

Stability of lutein encapsulated whey protein nano-emulsion during storage

PubMed Central

Guo, Mingruo

2018-01-01

Lutein is a hydrophobic carotenoid that has multiple health functions. However, the application of lutein is limited due to its poor solubility in water and instability under certain conditions during storage. Hereby we generated lutein loaded nano-emulsions using whey protein isolate (WPI) or polymerized whey protein isolate (PWP) with assistance of high intensity ultrasound and evaluate their stability during storage at different conditions. We measured the particle size, zeta-potential, physical stability and lutein content change. Results showed that the PWP based nano-emulsion system was not stable in the tested Oil/Water/Ethanol system indicated by the appearance of stratification within only one week. The WPI based nano-emulsion system showed stable physiochemical stability during the storage at 4°C. The lutein content of the system was reduced by only 4% after four weeks storage at 4°C. In conclusion, our whey protein based nano-emulsion system provides a promising strategy for encapsulation of lutein or other hydrophobic bioactive molecules to expand their applications. PMID:29415071

PHEA-PLA biocompatible nanoparticles by technique of solvent evaporation from multiple emulsions.

PubMed

Cavallaro, Gennara; Craparo, Emanuela Fabiola; Sardo, Carla; Lamberti, Gaetano; Barba, Anna Angela; Dalmoro, Annalisa

2015-11-30

Nanocarriers of amphiphilic polymeric materials represent versatile delivery systems for poorly water soluble drugs. In this work the technique of solvent evaporation from multiple emulsions was applied to produce nanovectors based on new amphiphilic copolymer, the α,β-poly(N-2-hydroxyethyl)-DL-aspartamide-polylactic acid (PHEA-PLA), purposely synthesized to be used in the controlled release of active molecules poorly soluble in water. To this aim an amphiphilic derivative of PHEA, a hydrophilic polymer, was synthesized by derivatization of the polymeric backbone with hydrophobic grafts of polylactic acid (PLA). The achieved copolymer was thus used to produce nanoparticles loaded with α tocopherol (vitamin E) adopted as lipophilic model molecule. Applying a protocol based on solvent evaporation from multiple emulsions assisted by ultrasonic energy and optimizing the emulsification process (solvent selection/separation stages), PHEA-PLA nanostructured particles with total α tocopherol entrapment efficiency (100%), were obtained. The drug release is expected to take place in lower times with respect to PLA due to the presence of the hydrophilic PHEA, therefore the produced nanoparticles can be used for semi-long term release drug delivery systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Influence of the Supramolecular Micro-Assembly of Multiple Emulsions on their Biopharmaceutical Features and In vivo Therapeutic Response.

PubMed

Cilurzo, Felisa; Cristiano, Maria Chiara; Di Marzio, Luisa; Cosco, Donato; Carafa, Maria; Ventura, Cinzia Anna; Fresta, Massimo; Paolino, Donatella

2015-01-01

The ability of some surfactants to self-assemble in a water/oil bi-phase environment thus forming supramolecular structure leading to the formation of w/o/w multiple emulsions was investigated. The w/o/w multiple emulsions obtained by self-assembling (one-step preparation method) were compared with those prepared following the traditional two-step procedure. Methyl-nicotinate was used as a hydrophilic model drug. The formation of the multiple emulsion structure was evidenced by optical microscopy, which showed a mean size of the inner oil droplets of 6 μm and 10 μm for one-step and two-step multiple emulsions, respectively. The in vitrobiopharmaceutical features of the various w/o/w multiple emulsion formulations were evaluated by means of viscosimetry studies, drug release and in vitro percutaneous permeation experiments through human stratum corneum and viable epidermis membranes. The self-assembled multiple emulsions allowed a more gradual percutaneous permeation (a zero-order permeation rate) than the two-step ones. The in vivotopical carrier properties of the two different multiple emulsions were evaluated on healthy human volunteers by using the spectrophotometry of reflectance, an in vivonon invasive method. These multiple emulsion systems were also compared with conventional emulsion formulations. Our findings demonstrated that the multiple emulsions obtained by self-assembling were able to provide a more sustained drug delivery into the skin and hence a longer therapeutic action than two-step multiple emulsions and conventional emulsion formulations. Finally, our findings showed that the supramolecular micro-assembly of multiple emulsions was able to influence not only the biopharmaceutical characteristics but also the potential in vivotherapeutic response.

Combinatorial and high-throughput approaches in polymer science

NASA Astrophysics Data System (ADS)

Zhang, Huiqi; Hoogenboom, Richard; Meier, Michael A. R.; Schubert, Ulrich S.

2005-01-01

Combinatorial and high-throughput approaches have become topics of great interest in the last decade due to their potential ability to significantly increase research productivity. Recent years have witnessed a rapid extension of these approaches in many areas of the discovery of new materials including pharmaceuticals, inorganic materials, catalysts and polymers. This paper mainly highlights our progress in polymer research by using an automated parallel synthesizer, microwave synthesizer and ink-jet printer. The equipment and methodologies in our experiments, the high-throughput experimentation of different polymerizations (such as atom transfer radical polymerization, cationic ring-opening polymerization and emulsion polymerization) and the automated matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MS) sample preparation are described.

Oil-in-oil-emulsions with enhanced substantivity for the treatment of chronic skin diseases.

PubMed

Lunter, Dominique Jasmin; Rottke, Michael; Daniels, Rolf

2014-05-01

The therapy of chronic skin diseases often requires several applications of creams or ointments per day. This is inconvenient to the patients and frequently leads to poor acceptance and compliance. We therefore developed oil-in-oil-emulsions that deliver the active pharmaceutical ingredient (API) to the skin over a prolonged period of time. In this study, we compare the permeation of the API from a conventional formulation to its permeation from an oil-in-oil-emulsion under infinite and finite dosing. Furthermore, we evaluate the substantivity of the formulations. Our results show that the permeation from oil-in-oil-emulsions is constant over a prolonged time and that the emulsions show significantly higher substantivity than conventional formulations. Because of that, the treatment intervals can be extended substantially and compliance can be increased. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Studies on the formation of polymeric nano-emulsions obtained via low-energy emulsification and their use as templates for drug delivery nanoparticle dispersions.

PubMed

Calderó, G; Montes, R; Llinàs, M; García-Celma, M J; Porras, M; Solans, C

2016-09-01

Ethylcellulose nanoparticles have been obtained from O/W nano-emulsions of the water/polyoxyethylene 10 oleyl ether/[ethyl acetate+4wt% ethylcellulose] system by low energy-energy emulsification at 25°C. Nano-emulsions with droplet sizes below 200nm and high kinetic stability were chosen for solubilising dexamethasone (DXM). Phase behaviour, conductivity and optical analysis studies of the system have evidenced for the first time that both, the polymer and the drug play a role on the structure of the aggregates formed along the emulsification path. Nano-emulsion formation may take place by both, phase inversion and self-emulsification. Spherical polymeric nanoparticles containing surfactant, showing sizes below 160nm have been obtained from the nano-emulsions by organic solvent evaporation. DXM loading in the nanoparticles was high (>90%). The release kinetics of nanoparticle dispersions with similar particle size and encapsulated DXM but different polymer to surfactant ratio were studied and compared to an aqueous DXM solution. Drug release from the nanoparticle dispersions was slower than from the aqueous solution. While the DXM solution showed a Fickian release pattern, the release behaviour from the nanoparticle dispersions was faster than that expected from a pure Fickian release. A coupled diffusion/relaxation model fitted the results very well, suggesting that polymer chains undergo conformational changes enhancing drug release. The contribution of diffusion and relaxation to drug transport in the nanoparticle dispersions depended on their composition and release time. Surfactant micelles present in the nanoparticle dispersion may exert a mild reservoir effect. The small particle size and the prolonged DXM release provided by the ethylcellulose nanoparticle dispersions make them suitable vehicles for controlled drug delivery applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Porous and magnetic molecularly imprinted polymers via Pickering high internal phase emulsions polymerization for selective adsorption of λ-cyhalothrin

NASA Astrophysics Data System (ADS)

Wu, Yunlong; Ma, Yue; Pan, Jianming; Gu, Runxing; Luo, Jialu

2017-03-01

A novel macroporous magnetic molecularly imprinted polymer (MMIPs) of was prepared by W/O Pickering (high internal phase emulsions) HIPEs polymerization, and then it was adopted as adsorbent for selective adsorption of λ-cyhalothrin (LC). In static conditions, adsorption capacity of LC increased rapidly in the first 60 min and reached to equilibrium in approximately 2.0 h. Excellent conformity of the second-order model confirmed the chemical nature of the interaction between the LC and imprinted sites. The fitting adsorption isotherm was a Langmuir type, and the maximum monolayer adsorption capacity at 298 K was 404.4 µmol g-1. Thermodynamic parameters suggested the specific adsorption at 298 K was an exothermic, spontaneous, and entropy decreased process. Competitive recognition studies of the MMIPs were performed with diethyl phthalate (DEP) and the structurally similar compound fenvalerate (FL), and the MMIPs, which displayed high selectivity for LC.

Porous and Magnetic Molecularly Imprinted Polymers via Pickering High Internal Phase Emulsions Polymerization for Selective Adsorption of λ-Cyhalothrin.

PubMed

Wu, Yunlong; Ma, Yue; Pan, Jianming; Gu, Runxing; Luo, Jialu

2017-01-01

A novel macroporous magnetic molecularly imprinted polymer (MMIPs) of was prepared by W/O Pickering (high internal phase emulsions) HIPEs polymerization, and then it was adopted as adsorbent for selective adsorption of λ-cyhalothrin (LC). In static conditions, adsorption capacity of LC increased rapidly in the first 60 min and reached to equilibrium in ~2.0 h. Excellent conformity of the second-order model confirmed the chemical nature of the interaction between the LC and imprinted sites. The fitting adsorption isotherm was a Langmuir type, and the maximum monolayer adsorption capacity at 298 K was 404.4 μmol g -1 . Thermodynamic parameters suggested the specific adsorption at 298 K was an exothermic, spontaneous, and entropy decreased process. Competitive recognition studies of the MMIPs were performed with diethyl phthalate (DEP) and the structurally similar compound fenvalerate (FL), and the MMIPs, which displayed high selectivity for LC.

Porous and Magnetic Molecularly Imprinted Polymers via Pickering High Internal Phase Emulsions Polymerization for Selective Adsorption of λ-Cyhalothrin

PubMed Central

Wu, Yunlong; Ma, Yue; Pan, Jianming; Gu, Runxing; Luo, Jialu

2017-01-01

A novel macroporous magnetic molecularly imprinted polymer (MMIPs) of was prepared by W/O Pickering (high internal phase emulsions) HIPEs polymerization, and then it was adopted as adsorbent for selective adsorption of λ-cyhalothrin (LC). In static conditions, adsorption capacity of LC increased rapidly in the first 60 min and reached to equilibrium in ~2.0 h. Excellent conformity of the second-order model confirmed the chemical nature of the interaction between the LC and imprinted sites. The fitting adsorption isotherm was a Langmuir type, and the maximum monolayer adsorption capacity at 298 K was 404.4 μmol g−1. Thermodynamic parameters suggested the specific adsorption at 298 K was an exothermic, spontaneous, and entropy decreased process. Competitive recognition studies of the MMIPs were performed with diethyl phthalate (DEP) and the structurally similar compound fenvalerate (FL), and the MMIPs, which displayed high selectivity for LC. PMID:28401145

Sequence-controlled methacrylic multiblock copolymers via sulfur-free RAFT emulsion polymerization

NASA Astrophysics Data System (ADS)

Engelis, Nikolaos G.; Anastasaki, Athina; Nurumbetov, Gabit; Truong, Nghia P.; Nikolaou, Vasiliki; Shegiwal, Ataulla; Whittaker, Michael R.; Davis, Thomas P.; Haddleton, David M.

2017-02-01

Translating the precise monomer sequence control achieved in nature over macromolecular structure (for example, DNA) to whole synthetic systems has been limited due to the lack of efficient synthetic methodologies. So far, chemists have only been able to synthesize monomer sequence-controlled macromolecules by means of complex, time-consuming and iterative chemical strategies such as solid-state Merrifield-type approaches or molecularly dissolved solution-phase systems. Here, we report a rapid and quantitative synthesis of sequence-controlled multiblock polymers in discrete stable nanoscale compartments via an emulsion polymerization approach in which a vinyl-terminated macromolecule is used as an efficient chain-transfer agent. This approach is environmentally friendly, fully translatable to industry and thus represents a significant advance in the development of complex macromolecule synthesis, where a high level of molecular precision or monomer sequence control confers potential for molecular targeting, recognition and biocatalysis, as well as molecular information storage.

Porous Polystyrene Monoliths and Microparticles Prepared from Core Cross-linked Star (CCS) Polymers-Stabilized Emulsions.

PubMed

Chen, Qijing; Shi, Ting; Han, Fei; Li, Zihan; Lin, Chao; Zhao, Peng

2017-08-17

A hydrophobic CCS polymer of poly(benzyl methacrylate) (PBzMA) was prepared in toluene by reversible addition-fragmentation chain transfer (RAFT)-mediated dispersion polymerization. The CCS polymer, with poly(benzyl methacrylate) as the arm and crosslinked N, N'-bis(acryloyl)cystamine (BAC) as the core, was confirmed by characterization with gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy. Three kinds of oils (toluene, anisole and styrene) were chosen to study the emulsification properties of PBzMA CCS polymer. The oils can be emulsified by CCS polymer to form water-in-oil (w/o) emulsions. Moreover, w/o high internal phase emulsions (HIPEs) can be obtained with the increase of toluene and styrene volume fractions from 75% to 80%. Porous polystyrene monolith and microparticles were prepared from the emulsion templates and characterized by the scanning electronic microscopy (SEM). With the internal phase volume fraction increased, open-pore porous monolith was obtained.

Oil-in-water emulsions stabilised by cellulose ethers: stability, structure and in vitro digestion.

PubMed

Borreani, Jennifer; Espert, María; Salvador, Ana; Sanz, Teresa; Quiles, Amparo; Hernando, Isabel

2017-04-19

The effect of cellulose ethers in oil-in-water emulsions on stability during storage and on texture, microstructure and lipid digestibility during in vitro gastrointestinal digestion was investigated. All the cellulose ether emulsions showed good physical and oxidative stability during storage. In particular, the methylcellulose with high methoxyl substituents (HMC) made it possible to obtain emulsions with high consistency which remained almost unchanged during gastric digestion, and thus could enhance fullness and satiety perceptions at gastric level. Moreover, the HMC emulsion slowed down lipid digestion to a greater extent than a conventional protein emulsion or the emulsions stabilised by the other cellulose ethers. Therefore, HMC emulsions could be used in weight management to increase satiation capacity and decrease lipid digestion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Wenwen; Wang, Weiyu; Li, Hui

In this study, high molecular weight “comb-shaped” graft copolymers, poly(isoprene-g-styrene), with polyisoprene as the backbone and polystyrene as side chains, were synthesized via free radical emulsion polymerization by copolymerization of isoprene with a polystyrene macromonomer synthesized using anionic polymerization. A small amount of toluene was used in order to successfully disperse the macromonomer. Both a redox and thermal initiation system were used in the emulsion polymerization, and the latex particle size and distribution were investigated by dynamic light scattering. The structural characteristics of the macromonomer and comb graft copolymers were investigated through use of size exclusion chromatography, spectroscopy, microscopy, thermalmore » analysis, and rheology. While the macromonomer was successfully copolymerized to obtain the desired multigraft copolymers, small amounts of unreacted macromonomer remained in the products, reflecting its reduced reactivity due to steric effects. Nevertheless, the multigraft copolymers obtained were very high in molecular weight (5–12 × 10 5 g/mol) and up to 10 branches per chain, on average, could be incorporated. A material incorporating 29 wt% polystyrene exhibits a disordered microphase separated morphology and elastomeric properties. As a result, these materials show promise as new, highly tunable, and potentially low cost thermoplastic elastomers.« less

Influence of membrane material on the production of colloidal emulsions by premix membrane emulsification.

PubMed

Gehrmann, Sandra; Bunjes, Heike

2018-05-01

Premix membrane emulsification is a possibility to produce colloidal emulsions as carrier systems for poorly water soluble drugs. During the extrusion of a coarse pre-emulsion through a porous membrane, the emulsion droplets are disrupted into smaller droplets. The influence of the membrane material on the emulsification success was investigated in dependence on the emulsifier. Premixed medium chain triglyceride (MCT) emulsions stabilized with five different emulsifiers were extruded through seven different hydrophilic polymeric membrane materials with pore sizes of 200nm. The resulting emulsions differed strongly in particle size and particle size distribution with a range of median particle sizes between 0.08μm and 11μm. The particle size of the emulsions did not depend mainly on the structure or thickness of the membrane but on the combination of emulsifier and membrane material. Contact angle measurements indicated that the wetting of the membrane with the continuous phase of the emulsion was decisive for achieving emulsions with colloidal particle sizes. The type of dispersed phase was of minor importance as basically the same results were obtained with peanut oil instead of MCT. To prove the assumption that only sufficiently hydrophilic membrane materials led to emulsions with colloidal particle sizes, two membrane materials were hydrophilized by plasma treatment. After hydrophilization, the emulsifying process led to emulsions with smaller particle sizes. The use of an alumina membrane (Anodisc®) improved the process even more. With this type of membrane, emulsions with a median particle size below 250nm and a narrow particle size distribution could be obtained with all investigated emulsifiers. Copyright © 2016 Elsevier B.V. All rights reserved.

Selective removal of erythromycin by magnetic imprinted polymers synthesized from chitosan-stabilized Pickering emulsion.

PubMed

Ou, Hongxiang; Chen, Qunhui; Pan, Jianming; Zhang, Yunlei; Huang, Yong; Qi, Xueyong

2015-05-30

Magnetic imprinted polymers (MIPs) were synthesized by Pickering emulsion polymerization and used to adsorb erythromycin (ERY) from aqueous solution. The oil-in-water Pickering emulsion was stabilized by chitosan nanoparticles with hydrophobic Fe3O4 nanoparticles as magnetic carrier. The imprinting system was fabricated by radical polymerization with functional and crosslinked monomer in the oil phase. Batches of static and dynamic adsorption experiments were conducted to analyze the adsorption performance on ERY. Isotherm data of MIPs well fitted the Freundlich model (from 15 °C to 35 °C), which indicated heterogeneous adsorption for ERY. The ERY adsorption capacity of MIPs was about 52.32 μmol/g at 15 °C. The adsorption kinetics was well described by the pseudo-first-order model, which suggested that physical interactions were primarily responsible for ERY adsorption. The Thomas model used in the fixed-bed adsorption design provided a better fit to the experimental data. Meanwhile, ERY exhibited higher affinity during adsorption on the MIPs compared with the adsorption capacity of azithromycin and chloramphenicol. The MIPs also exhibited excellent regeneration capacity with only about 5.04% adsorption efficiency loss in at least three repeated adsorption-desorption cycles. Copyright © 2015 Elsevier B.V. All rights reserved.

Model Filled Polymers. 6. Determination of the Crosslink Density of Polymeric Beads by Swelling

DTIC Science & Technology

1990-08-22

7 References [1] M. Mooney , J. AppI. Phys., 11, 582 (1940). [2] R. S. Rivlin , and D. W. Sanders, Trans. Faraday Soc., 48, 200 (1952). [31 P. J. Flory...microbeads ranging in diameter from 0.2 to 1 p were prepared by emulsion polymerization in the absence of emulsifier [23]. Polytetrafluorethylene ( PTFE ...density of polymethyl methacrylate is 1.17 g/cm3 [201. Swelling A PTFE ultrafiltration membrane is weighed and inserted in a concave configuration

Ionene modified small polymeric beads

NASA Technical Reports Server (NTRS)

Rembaum, Alan (Inventor)

1977-01-01

Linear ionene polyquaternary cationic polymeric segments are bonded by means of the Menshutkin reaction (quaternization) to biocompatible, extremely small, porous particles containing halide or tertiary amine sites which are centers for attachment of the segments. The modified beads in the form of emulsions or suspensions offer a large, positively-charged surface area capable of irreversibly binding polyanions such as heparin, DNA, RNA or bile acids to remove them from solution or of reversibly binding monoanions such as penicillin, pesticides, sex attractants and the like for slow release from the suspension.

Nano-formulations of drugs: Recent developments, impact and challenges.

PubMed

Jeevanandam, Jaison; Chan, Yen San; Danquah, Michael K

2016-01-01

Nano-formulations of medicinal drugs have attracted the interest of many researchers for drug delivery applications. These nano-formulations enhance the properties of conventional drugs and are specific to the targeted delivery site. Dendrimers, polymeric nanoparticles, liposomes, nano-emulsions and micelles are some of the nano-formulations that are gaining prominence in pharmaceutical industry for enhanced drug formulation. Wide varieties of synthesis methods are available for the preparation of nano-formulations to deliver drugs in biological system. The choice of synthesis methods depend on the size and shape of particulate formulation, biochemical properties of drug, and the targeted site. This article discusses recent developments in nano-formulation and the progressive impact on pharmaceutical research and industries. Additionally, process challenges relating to consistent generation of nano-formulations for drug delivery are discussed. Copyright © 2016 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruan, Guihua, E-mail: guihuaruan@hotmail.com; Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004; Wu, Zhenwei

A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of N{sub α}-benzoyl-L-arginine ethyl ester to N{sub α}-benzoyl-L-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast andmore » easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas. - Graphical abstract: Schematic illustration of preparation of hypercrosslinking polyHIPE immobilized enzyme reactor for on-column protein digestion. - Highlights: • A reactor was prepared and used for enzyme immobilization and continuous on-column protein digestion. • The new polyHIPE IMER was quite suit for protein digestion with good properties. • On-column digestion revealed that the IMER was easy regenerated by HCl without any structure destruction.« less

Cellulose nanofibrils for one-step stabilization of multiple emulsions (W/O/W) based on soybean oil.

PubMed

Carrillo, Carlos A; Nypelö, Tiina E; Rojas, Orlando J

2015-05-01

Cellulose nanofibrils (CNF) were incorporated in water-in-oil (W/O) microemulsions and emulsions, as well as water-in-oil-in-water (W/O/W) multiple emulsions using soybean oil. The addition of CNF to the aqueous phase expanded the composition range to obtain W/O/W emulsions. CNF also increased the viscosity of the continuous phase and reduced the drop size both of which increased the stability and effective viscosity of the emulsions. The effects of oil type and polarity on the properties of the W/O/W emulsions were tested with limonene and octane, which compared to soybean oil produced a smaller emulsion drop size, and thus a higher emulsion viscosity. Overall, CNF are a feasible alternative to conventional polysaccharides as stability enhancers for normal and multiple emulsions that exhibit strong shear thinning behavior. Copyright © 2014 Elsevier Inc. All rights reserved.

Bespoke contrast-matched diblock copolymer nanoparticles enable the rational design of highly transparent Pickering double emulsions

NASA Astrophysics Data System (ADS)

Rymaruk, Matthew J.; Thompson, Kate L.; Derry, Matthew J.; Warren, Nicholas J.; Ratcliffe, Liam P. D.; Williams, Clive N.; Brown, Steven L.; Armes, Steven P.

2016-07-01

We report the preparation of highly transparent oil-in-water Pickering emulsions using contrast-matched organic nanoparticles. This is achieved via addition of judicious amounts of either sucrose or glycerol to an aqueous dispersion of poly(glycerol monomethacrylate)56-poly(2,2,2-trifluoroethyl methacrylate)500 [PGMA-PTFEMA] diblock copolymer nanoparticles prior to high shear homogenization with an equal volume of n-dodecane. The resulting Pickering emulsions comprise polydisperse n-dodecane droplets of 20-100 μm diameter and exhibit up to 96% transmittance across the visible spectrum. In contrast, control experiments using non-contrast-matched poly(glycerol monomethacrylate)56-poly(benzyl methacrylate)300 [PGMA56-PBzMA300] diblock copolymer nanoparticles as a Pickering emulsifier only produced conventional highly turbid emulsions. Thus contrast-matching of the two immiscible phases is a necessary but not sufficient condition for the preparation of highly transparent Pickering emulsions: it is essential to use isorefractive nanoparticles in order to minimize light scattering. Furthermore, highly transparent oil-in-water-in-oil Pickering double emulsions can be obtained by homogenizing the contrast-matched oil-in-water Pickering emulsion prepared using the PGMA56-PTFEMA500 nanoparticles with a contrast-matched dispersion of hydrophobic poly(lauryl methacrylate)39-poly(2,2,2-trifluoroethyl methacrylate)800 [PLMA39-PTFEMA800] diblock copolymer nanoparticles in n-dodecane. Finally, we show that an isorefractive oil-in-water Pickering emulsion enables fluorescence spectroscopy to be used to monitor the transport of water-insoluble small molecules (pyrene and benzophenone) between n-dodecane droplets. Such transport is significantly less efficient than that observed for the equivalent isorefractive surfactant-stabilized emulsion. Conventional turbid emulsions do not enable such a comparison to be made because the intense light scattering leads to substantial spectral attenuation.We report the preparation of highly transparent oil-in-water Pickering emulsions using contrast-matched organic nanoparticles. This is achieved via addition of judicious amounts of either sucrose or glycerol to an aqueous dispersion of poly(glycerol monomethacrylate)56-poly(2,2,2-trifluoroethyl methacrylate)500 [PGMA-PTFEMA] diblock copolymer nanoparticles prior to high shear homogenization with an equal volume of n-dodecane. The resulting Pickering emulsions comprise polydisperse n-dodecane droplets of 20-100 μm diameter and exhibit up to 96% transmittance across the visible spectrum. In contrast, control experiments using non-contrast-matched poly(glycerol monomethacrylate)56-poly(benzyl methacrylate)300 [PGMA56-PBzMA300] diblock copolymer nanoparticles as a Pickering emulsifier only produced conventional highly turbid emulsions. Thus contrast-matching of the two immiscible phases is a necessary but not sufficient condition for the preparation of highly transparent Pickering emulsions: it is essential to use isorefractive nanoparticles in order to minimize light scattering. Furthermore, highly transparent oil-in-water-in-oil Pickering double emulsions can be obtained by homogenizing the contrast-matched oil-in-water Pickering emulsion prepared using the PGMA56-PTFEMA500 nanoparticles with a contrast-matched dispersion of hydrophobic poly(lauryl methacrylate)39-poly(2,2,2-trifluoroethyl methacrylate)800 [PLMA39-PTFEMA800] diblock copolymer nanoparticles in n-dodecane. Finally, we show that an isorefractive oil-in-water Pickering emulsion enables fluorescence spectroscopy to be used to monitor the transport of water-insoluble small molecules (pyrene and benzophenone) between n-dodecane droplets. Such transport is significantly less efficient than that observed for the equivalent isorefractive surfactant-stabilized emulsion. Conventional turbid emulsions do not enable such a comparison to be made because the intense light scattering leads to substantial spectral attenuation. Electronic supplementary information (ESI) available: GPC chromatograms, additional transmission electron micrographs, digital photographs, visible absorption spectra and laser diffraction data, further optical and fluorescence micrographs. See DOI: 10.1039/c6nr03856e

Polyacrylates with High Biomass Contents for Pressure-Sensitive Adhesives Prepared via Mini-emulsion Polymerization

Treesearch

Gang Pu; Matthew R. Dubay; Jiguang Zhang; Steven J. Severtson; Carl J. Houtman

2012-01-01

n-Butyl acrylate and other acrylic monomers were copolymerized with an acrylated macromonomer to produce polymers for pressure-sensitive adhesive (PSA) applications. Macromonomers were generated through the ring-opening copolymerization of L-lactide and ε-caprolactone with 2-hydroxyethyl...

Reduced Graphene Oxide-Hybridized Polymeric High-Internal Phase Emulsions for Highly Efficient Removal of Polycyclic Aromatic Hydrocarbons from Water Matrix.

PubMed

Huang, Yipeng; Zhang, Wenjuan; Ruan, Guihua; Li, Xianxian; Cong, Yongzheng; Du, Fuyou; Li, Jianping

2018-03-27

Reduced graphene oxide (RGO)-hybridized polymeric high-internal phase emulsions (RGO/polyHIPEs) with an open-cell structure and hydrophobicity have been successfully prepared using 2-ethylhexyl acrylate and ethylene glycol dimethacrylate as the monomer and the cross-linker, respectively. The adsorption mechanism and performance of this RGO/polyHIPEs to polycyclic aromatic hydrocarbons (PAHs) were investigated. Adsorption isotherms of PAHs on RGO/polyHIPEs show that the saturated adsorption capacity is 47.5 mg/g and the equilibrium time is 8 h. Cycling tests show that the adsorption capacity of RGO/polyHIPEs remains stable in 10 adsorption-desorption cycles without observable structure change in RGO/polyHIPEs. Moreover, the PAH residues in water samples after being purified by RGO/polyHIPEs are lower than the limit values in drinking water set by the European Food Safety Authority. These results demonstrate that the RGO/polyHIPEs have great potentiality in PAH removal and water purification.

Carbon dioxide-in-oil emulsions stabilized with silicone-alkyl surfactants for waterless hydraulic fracturing.

PubMed

Alzobaidi, Shehab; Lee, Jason; Jiries, Summer; Da, Chang; Harris, Justin; Keene, Kaitlin; Rodriguez, Gianfranco; Beckman, Eric; Perry, Robert; Johnston, Keith P; Enick, Robert

2018-09-15

The design of surfactants for CO 2 /oil emulsions has been elusive given the low CO 2 -oil interfacial tension, and consequently, low driving force for surfactant adsorption. Our hypothesis is that waterless, high pressure CO 2 /oil emulsions can be stabilized by hydrophobic comb polymer surfactants that adsorb at the interface and sterically stabilize the CO 2 droplets. The emulsions were formed by mixing with an impeller or by co-injecting CO 2 and oil through a beadpack (CO 2 volume fractions (ϕ) of 0.50-0.90). Emulsions were generated with comb polymer surfactants with a polydimethylsiloxane (PDMS) backbone and pendant linear alkyl chains. The C 30 alkyl chains are CO 2 -insoluble but oil soluble (oleophilic), whereas PDMS with more than 50 repeat units is CO 2 -philic but only partially oleophilic. The adsorbed surfactants sterically stabilized CO 2 droplets against Ostwald ripening and coalescence. The optimum surfactant adsorption was obtained with a PDMS degree of polymerization of ∼88 and seven C 30 side chains. The emulsion apparent viscosity reached 18 cP at a ϕ of 0.70, several orders of magnitude higher than the viscosity of pure CO 2 , with CO 2 droplets in the 10-150 µm range. These environmentally benign waterless emulsions are of interest for hydraulic fracturing, especially in water-sensitive formations. Copyright © 2018 Elsevier Inc. All rights reserved.

Dimensional change in complete dentures fabricated by injection molding and microwave processing.

PubMed

Keenan, Phillip L J; Radford, David R; Clark, Robert K F

2003-01-01

Acrylic resin complete dentures undergo dimensional changes during polymerization. Techniques with injection molding and polymerization and microwave polymerization are reported to reduce these changes and thereby improve clinical fit. These dimensional changes need to be quantified. The purpose of this study was to compare differences in dimensional changes of simulated maxillary complete dentures during polymerization and storage in water after injection molding and conventional polymerization, or microwave polymerization against a control of conventionally packed and polymerized simulated maxillary complete dentures. Forty identical maxillary denture bases were prepared in dental wax with anatomic teeth. They were invested and the wax eliminated from the molds. Ten specimens each were randomly assigned to 1 of 4 groups. Group 1 was compression molded and conventionally polymerized; group 2 was injection molded and conventionally polymerized (Success); group 3 was injection molded and microwave polymerized (Acron MC); and group 4 was injection molded and microwave polymerized (Microbase). Intermolar width and changes in vertical dimension of occlusion, were determined after polymerization and after storage in water for 28 days. Measurements in triplicate were made between points scribed on the second molar teeth with a traveling microscope (accurate to 0.005 mm). Vertical dimension of occlusion was measured between points scribed on the upper and lower members of an articulator by use of an internal micrometer (accurate to 0.05 mm). Data were analyzed by use of a 1-way analysis of variance with Tukey post-hoc contrasts (P <.05). Polymerization contractions (intermolar widths) for each group were: group 1, -0.24%; group 2, -0.27%; group 3, -0.35%; and group 4, -0.37%. The Microbase specimens had greater shrinkage than conventionally polymerized specimens, but there were no significant differences between the groups. All injection methods had less postpolymerization increase in vertical dimension of occlusion (0.63 to 0.41 mm) than the conventional Trevalon control (0.74 mm), but only group 4 was significantly different (P<.004). After storage in water for 28 days, all specimens increased in vertical dimension of occlusion (0.10% to 0.16%) from polymerization techniques, but there were no significant differences between groups. Within the limitations of this study, injection molding resulted in a slightly less increase of vertical dimension of occlusion than conventional polymerization techniques, the difference being significant for Microbase compared with the conventional Trevalon control.

Feasibility of the Simultaneous Determination of Monomer Concentrations and Particle Size in Emulsion Polymerization Using in Situ Raman Spectroscopy

PubMed Central

2015-01-01

An immersion Raman probe was used in emulsion copolymerization reactions to measure monomer concentrations and particle sizes. Quantitative determination of monomer concentrations is feasible in two-monomer copolymerizations, but only the overall conversion could be measured by Raman spectroscopy in a four-monomer copolymerization. The feasibility of measuring monomer conversion and particle size was established using partial least-squares (PLS) calibration models. A simplified theoretical framework for the measurement of particle sizes based on photon scattering is presented, based on the elastic-sphere-vibration and surface-tension models. PMID:26900256

Amphiphilic Soft Janus Particles as Interfacial Stabilizers

NASA Astrophysics Data System (ADS)

Wang, Wenda; Niu, Sunny; Sosa, Chris; Prud'Homme, Robert; Priestley, Rodney; Priestley Polymer Group Team; Prud'homme Research Group Team

Janus particles, which incorporate two or more ``faces'' with different chemical functionality, have attracted great attention in scientific research. Amphiphilic Janus particles have two faces with distinctly different hydrophobicity. This can be thought of as colloidal surfactants. Theoretical studies on the stabilization of emulsions using Janus particles have confirmed higher efficiency. Herein we synthesize the narrow distributed amphiphilic polymeric Janus particles via Precipitation-Induced Self-Assembly (PISA). The efficiency of the amphiphilic Janus particles are tested on different oil/water systems. Biocompatible polymers can also be used on this strategy and may potentially have wide application for food emulsion, cosmetics and personal products.

Surface Functionalization Methods to Enhance Bioconjugation in Metal-Labeled Polystyrene Particles

PubMed Central

Abdelrahman, Ahmed I.; Thickett, Stuart C.; Liang, Yi; Ornatsky, Olga; Baranov, Vladimir; Winnik, Mitchell A.

2011-01-01

Lanthanide-encoded polystyrene particles synthesized by dispersion polymerization are excellent candidates for mass cytometry based immunoassays, however they have previously lacked the ability to conjugate biomolecules to the particle surface. We present here three approaches to post-functionalize these particles, enabling the covalent attachment of proteins. Our first approach used partially hydrolyzed poly(N-vinylpyrrolidone) as a dispersion polymerization stabilizer to synthesize particles with high concentration of -COOH groups on the particle surface. In an alternative strategy to provide -COOH functionality to the lanthanide-encoded particles, we employed seeded emulsion polymerization to graft poly(methacrylic acid) (PMAA) chains onto the surface of these particles. However, these two approaches gave little to no improvement in the extent of bioconjugation. In our third approach, seeded emulsion polymerization was subsequently used as a method to grow a functional polymer shell (in this case, poly(glycidyl methacrylate) (PGMA)) onto the surface of these particles, which proved highly successful. The epoxide-rich PGMA shell permitted extensive surface bioconjugation of NeutrAvidin, as probed by an Lu-labeled biotin reporter (ca. 7 × 105 binding events per particle with a very low amount of non-specific binding) and analyzed by mass cytometry. It was shown that coupling agents such as EDC were not needed, such was the reactivity of the particle surface. These particles were stable and the addition of a polymeric shell was shown did not affect the narrow lanthanide ion distribution within the particle interior as analyzed by mass cytometry. These particles represent the most promising candidates for the development of a highly multiplexed bioassay based on lanthanide-labeled particles to date. PMID:21799543

Characteristics of Nano-emulsion for Cold Thermal Storage

NASA Astrophysics Data System (ADS)

Fumoto, Koji; Kawaji, Masahiro; Kawanami, Tsuyoshi

Phase change emulsion (PCE) is novel kind of heat storage and heat transfer fluids. It has characteristics as follows; greater apparent specific heat and higher heat transfer abilities in the phase change temperature range than conventional single phase heat transfer fluid. In this paper, a phase change emulsion, which has droplet diameter distribution of nanometer, were prepared. The Nano-emulsion was formed by low energy emulsification methods, as known the phase inversion temperature (PIT) method. Physical properties, such as viscosity, diameter and its distribution of emulsion were investigated. Especially, the relationships between preparation method and the concentration of surfactant have been discussed in detail. The results show that the viscosity of the Nano-emulsion is lower than the micro-emulsion, which was made by same mixing ratio of surfactant and concentration of phase change material. In addition, the Nano-emulsion clarified that stability was higher than microemulsions.

Preparation and Characterization of Polymeric Nanoparticles: An Interdisciplinary Experiment

ERIC Educational Resources Information Center

Ramalho, Maria J.; Pereira, M. Carmo

2016-01-01

In this work, a laboratory experiment to introduce graduate students to nanotechnology is described. Students prepared poly(lactic-"co"-glycolic acid) (PLGA) nanoparticles using two different synthesis procedures, a single and a double emulsion-solvent evaporation method. The students also performed a physicochemical characterization of…

Purified phenolics from hydrothermal treatments of biomass: ability to protect sunflower bulk oil and model food emulsions from oxidation.

PubMed

Conde, Enma; Moure, Andrés; Domínguez, Herminia; Gordon, Michael H; Parajó, Juan Carlos

2011-09-14

The phenolic fractions released during hydrothermal treatment of selected feedstocks (corn cobs, eucalypt wood chips, almond shells, chestnut burs, and white grape pomace) were selectively recovered by extraction with ethyl acetate and washed with ethanol/water solutions. The crude extracts were purified by a relatively simple adsorption technique using a commercial polymeric, nonionic resin. Utilization of 96% ethanol as eluting agent resulted in 47.0-72.6% phenolic desorption, yielding refined products containing 49-60% w/w phenolics (corresponding to 30-58% enrichment with respect to the crude extracts). The refined extracts produced from grape pomace and from chestnut burs were suitable for protecting bulk oil and oil-in-water and water-in-oil emulsions. A synergistic action with bovine serum albumin in the emulsions was observed.

Glyconanobiotics: Novel carbohydrated nanoparticle antibiotics for MRSA and Bacillus anthracis.

PubMed

Abeylath, Sampath C; Turos, Edward; Dickey, Sonja; Lim, Daniel V

2008-03-01

This report describes the synthesis and evaluation of glycosylated polyacrylate nanoparticles that have covalently-bound antibiotics within their framework. The requisite glycosylated drug monomers were prepared from one of three known antibiotics, an N-sec-butylthio beta-lactam, ciprofloxacin, and a penicillin, by acylation with 3-O-acryloyl-1,2-O-isopropylidene-5,6 bis((chlorosuccinyl)oxy)-d-glucofuranose (7) or 6-O-acetyl-3-O-acryloyl-1,2-O-isopropylidene-5-(chlorosuccinyl)oxy-alpha-d-glucofuranose (10). These acrylated monomers were subjected to emulsion polymerization in a 7:3 (w:w) mixture of butyl acrylate-styrene in the presence of sodium dodecyl sulfate as surfactant (3 weight %) and potassium persulfate as a radical initiator (1 weight %). The resulting nanoparticle emulsions were characterized by dynamic light scattering and found to have similar diameters ( approximately 40 nm) and size distributions to those of our previously studied systems. Microbiological testing showed that the N-sec-butylthio beta-lactam and ciprofloxacin nanoparticles both have powerful in vitro activities against methicillin-resistant Staphylococcus aureus and Bacillus anthracis, while the penicillin-bound nanoparticles have no antimicrobial activity. This indicates the need for matching a suitable antibiotic with the nanoparticle carrier. Overall, the study shows that even relatively large, polar acrylate monomers (MW>1000 amu) can be efficiently incorporated into the nanoparticle matrix by emulsion polymerization, providing opportunities for further advances in nanomedicine.

Glyconanobiotics: Novel carbohydrated nanoparticle antibiotics for MRSA and Bacillus anthracis

PubMed Central

Abeylath, Sampath C.; Turos, Edward; Dickey, Sonja; Limb, Daniel V.

2008-01-01

This report describes the synthesis and evaluation of glycosylated polyacrylate nanoparticles that have covalently-bound antibiotics within their framework. The requisite glycosylated drug monomers were prepared from one of three known antibiotics, an N-sec-butylthio β-lactam, ciprofloxacin, and a penicillin, by acylation with 3-O-acryloyl-1,2-O-isopropylidene-5,6 bis((chlorosuccinyl)oxy)-D-glucofuranose (7) or 6-O-acetyl-3-O-acryloyl-1,2-O-isopropylidene-5-(chlorosuccinyl)oxy-α-D-glucofuranose (10). These acrylated monomers were subjected to emulsion polymerization in a 7:3 (w:w) mixture of butyl acrylate-styrene in the presence of sodium dodecyl sulfate as surfactant (3 weight %) and potassium persulfate as a radical initiator (1 weight %). The resulting nanoparticle emulsions were characterized by dynamic light scattering and found to have similar diameters (~40 nm) and size distributions to those of our previously studied systems. Microbiological testing showed that the N-sec-butylthio β-lactam and ciprofloxacin nanoparticles both have powerful in vitro activities against methicillin-resistant Staphylococcus aureus and Bacillus anthracis, while the penicillin-bound nanoparticles have no antimicrobial activity. This indicates the need for matching a suitable antibiotic with the nanoparticle carrier. Overall, the study shows that even relatively large, polar acrylate monomers (MW>1000 amu) can be efficiently incorporated into the nanoparticle matrix by emulsion polymerization, providing opportunities for further advances in nanomedicine. PMID:18063370

General route for the assembly of functional inorganic capsules.

PubMed

Akartuna, Ilke; Tervoort, Elena; Studart, André R; Gauckler, Ludwig J

2009-11-03

Semipermeable, hollow capsules are attractive materials for the encapsulation and delivery of active agents in food processing, pharmaceutical and agricultural industries, and biomedicine. These capsules can be produced by forming a solid shell of close packed colloidal particles, typically polymeric particles, at the surface of emulsion droplets. However, current methods to prepare such capsules may involve multistep chemical procedures to tailor the surface chemistry of particles or are limited to particles that exhibit inherently the right hydrophobic-hydrophilic balance to adsorb around emulsion droplets. In this work, we describe a general and simple method to fabricate semipermeable, inorganic capsules from emulsion droplets stabilized by a wide variety of colloidal metal oxide particles. The assembly of particles at the oil-water interface is induced by the in situ hydrophobization of the particle surface through the adsorption of short amphiphilic molecules. The adsorption of particles at the interface leads to stable capsules comprising a single layer of particles in the outer shell. Such capsules can be used in the wet state or can be further processed into dry capsules. The permeability of the capsules can be modified by filling the interstices between the shell particles with polymeric or inorganic species. Functional capsules with biocompatible, bioresorbable, heat-resistant, chemical-resistant, and magnetic properties were prepared using alumina, silica, iron oxide, or tricalcium phosphate as particles in the shell.

Emulsion design to improve the delivery of functional lipophilic components.

PubMed

McClements, David Julian

2010-01-01

The food industry has used emulsion science and technology for many years to create a diverse range of food products, such as milk, cream, soft drinks, nutritional beverages, dressings, mayonnaise, sauces, dips, deserts, ice cream, margarine, and butter. The majority of these food products are conventional oil-in-water (O/W) or water-in-oil (W/O) type emulsions. Recently, there has been increasing interest within the food industry in either improving or extending the functional performance of foods using novel structured emulsions. This article reviews recent developments in the creation of structured emulsions that could be used by the food and other industries, including nanoemulsions, multiple emulsions, multilayer emulsions, solid lipid particles, and filled hydrogel particles. These structured emulsions can be produced from food-grade [generally recognized as safe (GRAS)] ingredients (e.g., lipids, proteins, polysaccharides, surfactants, and minerals), using simple processing operations (e.g., mixing, homogenizing, and thermal processing). The structure, production, performance, and potential applications of each type of structured emulsion system are discussed.

Synthesis, characterization, and morphology study of poly(acrylamide-co-acrylic acid)-grafted-poly(styrene-co-methyl methacrylate) "raspberry"-shape like structure microgels by pre-emulsified semi-batch emulsion polymerization.

PubMed

Ramli, Ros Azlinawati; Hashim, Shahrir; Laftah, Waham Ashaier

2013-02-01

A novel microgels were polymerized using styrene (St), methyl methacrylate (MMA), acrylamide (AAm), and acrylic acid (AAc) monomers in the presence of N,N'-methylenebisacrylamide (MBA) cross-linker. Pre-emulsified monomer was first prepared followed by polymerizing monomers using semi-batch emulsion polymerization. Fourier Transform Infrared Spectroscopy (FTIR) and (1)H Nuclear Magnetic Resonance (NMR) were used to determine the chemical structure and to indentify the related functional group. Grafting and cross-linking of poly(acrylamide-co-acrilic acid)-grafted-poly(styrene-co-methyl methacrylate) [poly(AAm-co-AAc)-g-poly(St-co-MMA)] microgels are approved by the disappearance of band at 1300 cm(-1), 1200 cm(-1) and 1163 cm(-1) of FTIR spectrum and the appearance of CH peaks at 5.5-5.7 ppm in (1)H NMR spectrum. Scanning Electron Microscope (SEM) images indicated that poly(St-co-MMA) particle was lobed morphology coated by cross-linked poly(AAm-co-AAc) shell. Furthermore, SEM results revealed that poly(AAm-co-AAc)-g-poly(St-co-MMA) is composite particle that consist of "raspberry"-shape like structure core. Internal structures of the microgels showed homogeneous network of pores, an extensive interconnection among pores, thicker pore walls, and open network structures. Water absorbency test indicated that the sample with particle size 0.43 μm had lower equilibrium water content, % than the sample with particle size 7.39 μm. Copyright © 2012 Elsevier Inc. All rights reserved.

Water-in-oil Pickering emulsions stabilized by stearoylated microcrystalline cellulose.

PubMed

Pang, Bo; Liu, Huan; Liu, Peiwen; Peng, Xinwen; Zhang, Kai

2018-03-01

Hydrophobic particles with static water contact angles larger than 90° are more like to stabilize W/O Pickering emulsions. In particular, high internal phase Pickering emulsions (HIPEs) are of great interest for diverse applications. However, W/O HIPEs have rarely been realized using sustainable biopolymers. Herein, we used stearoylated microcrystalline cellulose (SMCC) to stabilize W/O Pickering emulsions and especially, W/O HIPEs. Moreover, these W/O HIPEs can be further used as platforms for the preparation of porous materials, such as porous foams. Stearoylated microcrystalline cellulose (SMCC) was prepared by modifying MCC with stearoyl chloride under heterogeneous conditions. Using SMCC as emulsifiers, W/O medium and high internal phase Pickering emulsions (MIPEs and HIPEs) with various organic solvents as continuous phases were prepared using one-step and two-step methods, respectively. Polystyrene (PS) foams were prepared after polymerization of oil phase using HIPEs as templates and their oil/water separation capacity were studied. SMCC could efficiently stabilize W/O Pickering emulsions and HIPEs could only be prepared via the two-step method. The internal phase volume fraction of the SMCC-stabilized HIPEs reached as high as 89%. Diverse internal phase volume fractions led to distinct inner structures of foams with closed or open cells. These macroporous polystyrene (PS) foams demonstrated great potential for the effective absorption of organic solvents from underwater. Copyright © 2017 Elsevier Inc. All rights reserved.

Physical Immobilization Liposomes in Uniform Zwitterionic Microgel Particles Fabricated in Microcapillary Device

NASA Astrophysics Data System (ADS)

Jeong, Eun Seon; Byun, Aram; Kim, Jin Woong

2014-03-01

Lipid molecules have both hydrophilic and hydrophobic properties. Since their packing parameter ranges from 0.5 to 1, they self-assemble to form a vesicle structure, liposome. Thanks to the vesicle structure, liposome is able to encapsulate both hydrophilic and hydrophobic active ingredients, thus widening its applicability to pharmaceutical, cosmetic, and food industry. However, its vesicular structure is readily transferred to micelle in the presence of amphiphilic additives with low packing parameters. Therefore, it is critical to developing a technique to overcome this drawback. This study introduces a microfluidic approach to physically immobilize liposome in microgel particles. For this, we generate a uniform liposome-in-oil-in-water emulsion in a capillary-based microfluidic device. Basically, we observe how the flows in micro-channels affect generation of embryo emulsion drops. Then, the uniform emulsion is solidified by using photo-polymerization. Finally, we characterize the particle morphology, membrane fluidity, and mesh property, encapsulation efficiency and releasing.

In situ quantification of β-carotene partitioning in oil-in-water emulsions by confocal Raman microscopy.

PubMed

Wan Mohamad, W A Fahmi; Buckow, Roman; Augustin, MaryAnn; McNaughton, Don

2017-10-15

Confocal Raman microscopy (CRM) was able to quantify the β-carotene concentration in oil droplets and determine the partitioning characteristics of β-carotene within the emulsion system in situ. The results were validated by a conventional method involving solvent extraction of β-carotene separately from the total emulsion as well as the aqueous phase separated by centrifugation, and quantification by absorption spectrophotometry. CRM also enabled the localization of β-carotene in an emulsion. From the Raman image, the β-carotene partitioning between the aqueous and oil phases of palm olein-in-water emulsions stabilized by whey protein isolate (WPI) was observed. Increasing the concentration of β-carotene in an emulsion (from 0.1 to 0.3g/kg emulsion) with a fixed gross composition (10% palm olein:2% WPI) decreased the concentration of β-carotene in the oil droplet. CRM is a powerful tool for in situ analyses of components in heterogeneous systems such as emulsions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fabrication and Properties of polyacrylic acid by ionic surfactant disturbance method

NASA Astrophysics Data System (ADS)

Lawan, S.; Osotchan, T.; Chuajiw, W.; Subannajui, K.

2017-09-01

The formation of polymeric materials can be achieved by several methods such as melting and casting, screw extrusion, cross-linking of resin or rubber in a mold, and so on. In this work, the polyacrylic acid is formed by using the emulsion disturbance method. Despite extensively used in the colour painting and coating industries, acrylic emulsion can be processed into a foam and powder configuration by a reaction between acrylic emulsion and salt. The solidification hardly changes the volume between liquid emulsion and solidified polymer which means the final structure of polyacrylic acid is filled with opened air cells. The opened air cell structure is confirmed by the result from scanning electron microscopy. The chemical analysis and crystallography of acrylic powder and foam are examined by Fourier-transform infrared spectroscopy and X-ray diffraction respectively. The phase transformation and Thermal stability are studied by differential scanning calorimetry and thermo gravimetric analysis. Moreover, the mechanical properties of acrylic foam were observed by tensile, compressive and hardness test. In addition to the basic property analysis, acrylic foam was also used in the particle filtration application.

Polymerization model for hydrogen peroxide initiated synthesis of polypyrrole nanoparticles.

PubMed

Leonavicius, Karolis; Ramanaviciene, Almira; Ramanavicius, Arunas

2011-09-06

A very simple, environmentally friendly, one-step oxidative polymerization route to fabricate polypyrrole (Ppy) nanoparticles of fixed size and morphology was developed and investigated. The herein proposed method is based on the application of sodium dodecyl sulfate and hydrogen peroxide, both easily degradable and cheap materials. The polymerization reaction is performed on 24 h time scale under standard conditions. We monitored a polaronic peak at 465 nm and estimated nanoparticle concentration during various stages of the reaction. Using this data we proposed a mechanism for Ppy nanoparticle formation in accordance with earlier emulsion polymerization mechanisms. Rates of various steps in the polymerization mechanism were accounted for and the resulting particles identified using atomic force microscopy. Application of Ppy nanoparticles prepared by the route presented here seems very promising for biomedical applications where biocompatibility is paramount. In addition, this kind of synthesis could be suitable for the development of solar cells, where very pure and low-cost conducting polymers are required. © 2011 American Chemical Society

Hg(II) adsorption using amidoximated porous acrylonitrile/itaconic copolymers prepared by suspended emulsion polymerization.

PubMed

Ji, Chunnuan; Qu, Rongjun; Chen, Hou; Liu, Xiguang; Sun, Changmei; Ma, Caixia

2016-01-01

Initially, porous acrylonitrile/itaconic acid copolymers (AN/IA) were prepared by suspended emulsion polymerization. Successively, the cyano groups in AN/IA copolymers were converted to amidoxime (AO) groups by the reaction with hydroxylamine hydrochloride. The structures of the AN/IA and amidoximated AN/IA (AO AN/IA) were characterized by infrared spectroscopy, scanning electron microscopy, and porous structural analysis. The adsorption properties of AO AN/IA for Hg(II) were investigated. The results show that AO AN/IA has mesopores and macropores, and surface area of 11.71 m(2) g(-1). It was found that AO AN/IA has higher affinity for Hg(II), with the maximum adsorption capacity of 84.25 mg g(-1). The AO AN/IA also can effectively remove Hg(II) from different binary metal ion mixture systems. Furthermore, the adsorption kinetics and thermodynamics were studied in detail. The adsorption equilibrium can quickly be achieved in 4 h determined by an adsorption kinetics study. The adsorption process is found to belong to the second-order model, and can be described by the Freundlich model.

Super-enhanced particle nucleation in styrene emulsion polymerization in the presence of sodium styrene sulfonate.

PubMed

Farias-Cepeda, Lorena; Herrera-Ordonez, Jorge; Hernandez-Martinez, Angel R; Estevez, Miriam; Rosales-Marines, Lucero

2017-08-15

The styrene (St) emulsion polymerization using Aerosol MA80 as surfactant and in the presence of sodium styrene sulfonate (NaSS) was studied. The effect of NaSS content was assessed using MA80 concentrations below and at the critical micellar concentration. It was found that at the higher NaSS and MA80 contents, the number of particles (N) reaches a maximum of the order of 10 17 particles/cm 3 water, a huge value that has never been reported. In this work an explanation for this super-enhanced particle nucleation phenomenon is proposed. Such hypothesis is based on the role of St-NaSS oligomers formed in the aqueous phase and their synergy with MA80 molecules to provide colloidal stability to the system. The proposal seems to be consistent with the experimental data obtained for the evolution of monomer conversion, N, particles size distribution and the wideness of this latter as well as with a theoretical estimation of the N. Copyright © 2017 Elsevier Inc. All rights reserved.

Facile and low energy consumption synthesis of microencapsulated phase change materials with hybrid shell for thermal energy storage

NASA Astrophysics Data System (ADS)

Wang, Hao; Zhao, Liang; Chen, Lijie; Song, Guolin; Tang, Guoyi

2017-12-01

We designed a photocurable pickering emulsion polymerization to create microencapsulated phase change materials (MicroPCM) with polymer-silica hybrid shell. The emulsion was stabilized by modified SiO2 particles without any surfactant or dispersant. The polymerization process can be carried out at ambient temperature only for 5 min ultraviolet radiation, which is a low-energy procedure. The resultant capsules were shown a good core-shell structure and uniform in size. The surface of the microcapsules was covered by SiO2 particles. According to the DSC and TGA examinations, the microcapsules has good thermal energy storage-release performance, enhanced thermal reliability and thermal stability. When ratio of MMA/n-octadecane was 1.5/1.5. The encapsulation efficiency of the microcapsules reached 62.55%, accompanied with 122.31 J/g melting enthalpy. The work is virtually applicable to the construction of a wide variety of organic-inorganic hybrid shell MicroPCM. Furthermore, with the application of this method, exciting opportunities may arise for realizing rapid, continuous and large-scale industrial preparation of MicroPCM.

Structure-activity relationships of polyphenols to prevent lipid oxidation in pelagic fish muscle.

PubMed

Pazos, Manuel; Iglesias, Jacobo; Maestre, Rodrigo; Medina, Isabel

2010-10-27

The influence of polymerization (number of monomers) and galloylation (content of esterified gallates) of oligomeric catechins (proanthocyanidins) on their effectiveness to prevent lipid oxidation in pelagic fish muscle was evaluated. Non-galloylated oligomers of catechin with diverse mean polymerization (1.9-3.4 monomeric units) were extracted from pine (Pinus pinaster) bark. Homologous fractions with galloylation ranging from 0.25 to <1 gallate group per molecule were obtained from grape (Vitis vinifera) and witch hazel (Hamamelis virginiana). The results showed the convenience of proanthocyanidins with medium size (2-3 monomeric units) and low galloylation degree (0.15-0.25 gallate group/molecule) to inhibit lipid oxidation in pelagic fish muscle. These optimal structural characteristics of proanthocyanidins were similar to those lately reported in fish oil-in-water emulsions using phosphatidylcholine as emulsifier. This finding suggests that the antioxidant behavior of polyphenols in muscle-based foods can be mimicked in emulsions prepared with phospholipids as emulsifier agents. The present data give relevant information to achieve an optimum use of polyphenols in pelagic fish muscle.

Monodispersepoly[BMA-co-(COPS-I)] Particles by Soap-Free Emulsion Copolymerization and Its Optical Properties as Photonic Crystals.

PubMed

Lee, Ki Chang; Choo, Hun Seung

2015-10-01

In order to study the surfactant-free emulsion copolymerization of benzyl methacrylate (BMA) with sodium 1-allyloxy-2-hydroxypropane sulfonate (COPS-I) and the resulting optical properties, a series of experiments was carried out at various reaction conditions such as the changes of BMA concentration, COPS-I concentration, BMA concentration under a fixed COPS-I amount, initiator and divinyl benzene (DVB) concentration. All the latices showed highly monodispersed spherical particles in the size range of 144~435 nm and the respective shiny structural colors from their colloidal photonic crystals. It is found that the changes in such polymerization factors greatly affect the number of particles and particle diameter, polymerization rate, molecular weight, zeta-potential, and refractive indices. The increase of number of particles led to the increased rate of polymerization and zeta-potential of the latices, on the other hand, to the decreased molecular weight. Refractive indices and the reflectivity increased with COPS-I concentration, on the other hand, and decreased with DVB concentration. Especially, refractive indices of the resulting poly[BMA-co-(COPS-I)] colloidal photonic crystals showed much higher values of 1.65~2.21 than that of polystyrene, due to the formation of core-shell shaped morphology. Monodisperse and high refractive index of poly[BMA-co-(COPS-I)] particles prepared in this work could be used for the study in photonic crystals and electrophoretic display.

Liquid-liquid two phase systems for the production of porous hydrogels and hydrogel microspheres for biomedical applications: A tutorial review

PubMed Central

Elbert, Donald L.

2010-01-01

Macroporous hydrogels may have direct applications in regenerative medicine as scaffolds to support tissue formation. Hydrogel microspheres may be used as drug delivery vehicles or as building blocks to assemble modular scaffolds. A variety of techniques exist to produce macroporous hydrogels and hydrogel microspheres. A subset of these relies on liquid-liquid two phase systems. Within this subset, vastly different types of polymerization processes are found. In this review, the history, terminology and classification of liquid-liquid two phase polymerization and crosslinking are described. Instructive examples of hydrogel microsphere and macroporous scaffold formation by precipitation/dispersion, emulsion and suspension polymerizations are used to illustrate the nature of these processes. The role of the kinetics of phase separation in determining the morphology of scaffolds and microspheres is also delineated. Brief descriptions of miniemulsion, microemulsion polymerization and ionotropic gelation are also included. PMID:20659596

Selective boron delivery by intra-arterial injection of BSH-WOW emulsion in hepatic cancer model for neutron capture therapy

PubMed Central

Dewi, Novriana; Higashi, Syushi; Ikushima, Ichiro; Seguchi, Koji; Mizumachi, Ryoji; Murata, Yuji; Morishita, Yasuyuki; Shinohara, Atsuko; Mikado, Shoji; Yasuda, Nakahiro; Fujihara, Mitsuteru; Sakurai, Yuriko; Mouri, Kikue; Yanagawa, Masashi; Iizuka, Tomoya; Suzuki, Minoru; Sakurai, Yoshinori; Masunaga, Shin-ichiro; Tanaka, Hiroki; Matsukawa, Takehisa; Yokoyama, Kazuhito; Fujino, Takashi; Ogura, Koichi; Nonaka, Yasumasa; Sugiyama, Hirotaka; Kajiyama, Tetsuya; Yui, Sho; Nishimura, Ryohei; Ono, Koji; Takamoto, Sinichi; Nakajima, Jun; Ono, Minoru; Eriguchi, Masazumi; Hasumi, Kenichiro; Takahashi, Hiroyuki

2017-01-01

Objective: Boron neutron-capture therapy (BNCT) has been used to inhibit the growth of various types of cancers. In this study, we developed a 10BSH-entrapped water-in-oil-in-water (WOW) emulsion, evaluated it as a selective boron carrier for the possible application of BNCT in hepatocellular carcinoma treatment. Methods: We prepared the 10BSH-entrapped WOW emulsion using double emulsification technique and then evaluated the delivery efficacy by performing biodistribution experiment on VX-2 rabbit hepatic tumour model with comparison to iodized poppy-seed oil mix conventional emulsion. Neutron irradiation was carried out at Kyoto University Research Reactor with an average thermal neutron fluence of 5 × 1012 n cm−2. Morphological and pathological analyses were performed on Day 14 after neutron irradiation. Results: Biodistribution results have revealed that 10B atoms delivery with WOW emulsion was superior compared with those using iodized poppy-seed oil conventional emulsion. There was no dissemination in abdomen or lung metastasis observed after neutron irradiation in the groups treated with 10BSH-entrapped WOW emulsion, whereas many tumour nodules were recognized in the liver, abdominal cavity, peritoneum and bilateral lobes of the lung in the non-injected group. Conclusion: Tumour growth suppression and cancer-cell-killing effect was observed from the morphological and pathological analyses of the 10BSH-entrapped WOW emulsion-injected group, indicating its feasibility to be applied as a novel intra-arterial boron carrier for BNCT. Advances in knowledge: The results of the current study have shown that entrapped 10BSH has the potential to increase the range of therapies available for hepatocellular carcinoma which is considered to be one of the most difficult tumours to cure. PMID:28406315

Molecular Imprinting Techniques Used for the Preparation of Biosensors

PubMed Central

Ertürk, Gizem; Mattiasson, Bo

2017-01-01

Molecular imprinting is the technology of creating artificial recognition sites in polymeric matrices which are complementary to the template in their size, shape and spatial arrangement of the functional groups. Molecularly imprinted polymers (MIPs) and their incorporation with various transducer platforms are among the most promising approaches for detection of several analytes. There are a variety of molecular imprinting techniques used for the preparation of biomimetic sensors including bulk imprinting, surface imprinting (soft lithography, template immobilization, grafting, emulsion polymerization) and epitope imprinting. This chapter presents an overview of all of these techniques with examples from particular publications. PMID:28165419

Impact of Lipid and Protein Co-oxidation on Digestibility of Dairy Proteins in Oil-in-Water (O/W) Emulsions.

PubMed

Obando, Mónica; Papastergiadis, Antonios; Li, Shanshan; De Meulenaer, Bruno

2015-11-11

Enrichment of polyunsaturated fatty acids (PUFAs) is a growing trend in the food industry. However, PUFAs are known to be susceptible to lipid oxidation. It has been shown that oxidizing lipids react with proteins present in the food and that as a result polymeric protein complexes are produced. Therefore, the aim of this work was to investigate the impact of lipid and protein co-oxidation on protein digestibility. Casein and whey protein (6 mg/mL) based emulsions with 1% oil with different levels of PUFAs were subjected to respectively autoxidation and photo-oxidation. Upon autoxidation at 70 °C, protein digestibility of whey protein based emulsions containing fish oil decreased to 47.7 ± 0.8% after 48 h, whereas in the controls without oil 67.8 ± 0.7% was observed. Upon photo-oxidation at 4 °C during 30 days, mainly casein-based emulsions containing fish oil were affected: the digestibility amounted to 43.9 ± 1.2%, whereas in the control casein solutions without oil, 72.6 ± 0.2% of the proteins were digestible. Emulsions containing oils with high PUFA levels were more prone to lipid oxidation and thus upon progressive oxidation showed a higher impact on protein digestibility.

Breaking of the Bancroft rule for multiple emulsions stabilized by a single stimulable polymer.

PubMed

Besnard, L; Protat, M; Malloggi, F; Daillant, J; Cousin, F; Pantoustier, N; Guenoun, P; Perrin, P

2014-09-28

We investigated emulsions of water and toluene stabilized by (co)polymers consisting of styrene (S) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) monomer units with different compositions and structures such as a PDMAEMA homopolymer, a P(S-co-DMAEMA) random copolymer and various PS-b-PDMAEMA and PS-b-(S-co-DMAEMA) block copolymers. The model system is used to study the fundamental conditions under which the different kinds of polymer-stabilized emulsions (direct oil in water, inverse water in oil and multiple emulsions) are stabilized or destabilized by pH change (at constant temperature). Polymer properties like chain conformation at the toluene-water interface as probed by SANS and neutron reflectivity at the liquid-liquid interface, the oil-water partitioning of the polymer chains (Bancroft's rule of thumb) as determined by UV spectroscopy and interfacial tensions measured by the rising and spinning drop techniques are determined. Overall, results evidence that the curvature sign, as defined by positive and negative values as the chain segments occupy preferentially the water and toluene sides of the interface respectively, reliably predicts the emulsion kind. In contrast, the Bancroft rule failed at foreseeing the emulsion type. In the region of near zero curvature the crossover from direct to inverse emulsions occurs through the formation of either unstable coexisting direct and inverse emulsions (i) or multiple emulsions (ii). The high compact adsorption of the chains at the interface as shown by low interfacial tension values does not allow to discriminate between both cases. However, the toluene-water partitioning of the polymeric emulsifier is still a key factor driving the formation of (i) or (ii) emulsions. Interestingly, the stabilization of the multiple emulsions can be tuned to a large extent as the toluene-water polymer partitioning can be adjusted using quite a large number of physico-chemical parameters linked to polymer architecture like diblock length ratio or polymer total molar mass, for example. Moreover, we show that monitoring the oil-water partitioning aspect of the emulsion system can also be used to lower the interfacial tension at low pH to values slightly higher than 0.01 mN m(-1), irrespective of the curvature sign.

UV shielding with visible transparency based properties of poly (styrene-co-acrylonitrile)/Ag doped ZnO nanocomposite

NASA Astrophysics Data System (ADS)

Singh, Rajender; Verma, Karan; Singh, Tejbir; Barman, P. B.; Sharma, Dheeraj

2018-02-01

Development of ultraviolet (UV) shielding with visible transparency based thermoplastic polymer nanocomposite (PNs) presents an important requisite in terms of their efficiency and cost. Present study contributed for the same approach by dispersion of Ag doped ZnO nanoparticles upto 10 wt% in poly (styrene-co-acrylonitrile) matrix by insitu emulsion polymerization method. The crystal and chemical structure of PNs has been analyzed by x-ray diffraction (XRD) and fourier infrared spectrometer (FTIR) techniques. The morphological and elemental information of synthesized nanomaterial has been studied by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) technique. The optical properties of PNs has been studied by UV-visible spectroscopy technique. The incorporation of nanoparticles in polymer matrix absorb the complete UV light with visible transparency. The present reported polymer nanocomposite (PNs) have tuned refractive index with UV blocking and visible transparency based properties which can serve as a viable alternative as compared to related conventional materials.

Recent advances in developing ophthalmic formulations: a patent review.

PubMed

Lu, Guang Wei

2010-01-01

In an effort to improve the drug solubility, stability and/or ocular bioavailability of ophthalmic formulations,various approaches have been explored in the recent past. Additionally, different formulations have been investigated in order to seek those preservative systems that are more tolerable to the ocular tissue. Over the past ten years, inventions in ophthalmic formulations directed toward front-of-eye instillations have concentrated in the areas of new excipients' applications, novel and combined use of conventional excipients, and developments of novel dosage forms. Among these areas, applications of polymeric excipients, cyclodextrins and stabilized chloride dioxide (SCD) have been the most actively studied fields. In addition, oil-in-water (O/W) emulsions have been becoming more popular as an ophthalmic dosage form due to the potentials in increasing drug solubility, stabilizing active pharmaceutical ingredients (APIs), improving ocular tolerance, and providing palliative effects. Some of these innovations from the past decade have the capability of leading to new commercial products. This patent review has a useful knowledge in the advancement for treating various ophthalmic diseases.

Antifungal activity against Candida albicans of starch Pickering emulsion with thymol or amphotericin B in suspension and calcium alginate films.

PubMed

Cossu, Andrea; Wang, Min S; Chaudhari, Amol; Nitin, Nitin

2015-09-30

Conventional antifungal treatments against Candida albicans in the oral cavity often result in increased cytotoxicity. The goal of this study was to determine the potential of starch Pickering emulsion as a delivery vehicle for an antifungal natural phenolic compound such as thymol in simulated saliva fluid (SSF) compared to amphotericin B. An oil-in-water (o/w) emulsion was stabilized using starch particles. Physical stability of the emulsion and disruption induced by α-amylase activity in SSF was evaluated. Encapsulated thymol in o/w emulsion was compared to encapsulated amphotericin B for antifungal activity against C. albicans in suspension using emulsions or zone inhibition assay on agar plates using emulsions dispersed in alginate films. Results showed that the emulsions were stable for at least three weeks. Digestion of the emulsion by α-amylase led to coalescence of emulsion droplets. The antifungal activity of thymol and amphotericin B in emulsion formulation was enhanced upon incubation with α-amylase. Results from the zone inhibition assay demonstrated efficacy of the emulsions dispersed in alginate films. Interestingly, addition of α-amylase to the alginate films resulted in a decreased inhibitory effect. Overall, this study showed that starch Pickering emulsions have a potential to deliver hydrophobic antifungal compounds to treat oral candidiasis. Copyright © 2015 Elsevier B.V. All rights reserved.

Adsorption of the Three-phase Emulsion on Various Solid Surfaces.

PubMed

Enomoto, Yasutaka; Imai, Yoko; Tajima, Kazuo

2017-07-01

The present study investigates the adsorption of the three-phase emulsion on various solid/water interfaces. Vesicles can be used as emulsifiers in the three-phase emulsions and act as an independent phase unlike the surfactant used in conventional emulsions; therefore, it is expected that the three-phase emulsion formed by the adhesion of vesicles to the oil/water interface will adsorb on various solid/water interfaces. The cationic three-phase emulsion was prepared to encourage emulsion adsorption on negatively charged solid substrates in water. The emulsifier polyoxyethylene-(10) hydrogenated castor oil was rendered cationic by mixing with the surfactant cetyltrimethylammonium bromide and then used to prepare the cationic three-phase emulsion of hexadecane-in-water. Three solid substrates (silicon, glass, and copper) were dipped in the cationic emulsion and the emulsion was found to adsorb on the solid substrates while maintaining its structure. The amount of hexadecane adsorbed on the various surfaces was investigated by gas chromatography and found to increase with increasing hexadecane concentration in the emulsion and eventually plateaued just like molecular adsorption. The maximum surface coverage of the emulsion on the substrates was approximately 80%. However, even the equivalent nonionic three-phase emulsion was found to adsorb on the three solid surfaces. This was attributed to a novel mechanism of irreversible adhesion via the van der Waals attractive force.

Study to determine the technical and economic feasibility of reclaiming chemicals used in micellar polymer and low tension surfactant flooding. Final report. [Ultrafiltration membranes and reverse osmosis membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stephens, R.H.; Himmelblau, A.; Donnelly, R.G.

1978-02-01

Energy Resources Company has developed a technology for use with enhanced oil recovery to achieve emulsion breaking and surfactant recovery. By using ultrafiltration membranes, the Energy Resources Company process can dewater an oil-in-water type emulsion expected from enhanced oil recovery projects to the point where the emulsion can be inverted and treated using conventional emulsion-treating equipment. By using a tight ultrafiltration membrane or a reverse osmosis membrane, the Energy Resources Company process is capable of recovering chemicals such as surfactants used in micellar polymer flooding.

Rational design and evaluation of HBsAg polymeric nanoparticles as antigen delivery carriers.

PubMed

Dewangan, Hitesh Kumar; Pandey, Tarun; Maurya, Lakshmi; Singh, Sanjay

2018-05-01

The present work is focused on the development and evaluation of single dose sustained-release Hepatitis B surface antigen (HBsAg) loaded nanovaccine for Hepatitis B. The conventional treatment suffers from repeated administration and hence requires a booster dose. Therefore, polymeric nanovaccine of HBsAg was developed by double emulsion solvent evaporation technique, utilizing central composite design for formulation optimization. The effects of independent variables (like polymer amount, stabilizer concentration, aqueous/organic phase ratio and homogenizer speed) were also studied on critical quality attributes like particle size and entrapment efficiency. Nanovaccine was characterized in terms of physicochemical parameters, release, internalization and in vivo immunological evaluation in BALB/c mice after administration by different routes such as oral, sub-cutaneous, nasal and intramuscular. The designed nanovaccine demonstrated nanometric size with smooth surface, negative zeta potential, maximum entrapment, sustained release and better internalization in macrophage and MRC-5 cell line. The immune-stimulating activity of nanovaccine administered by different routes was evaluated by measuring anti-HBsAg titre like specific immunoglobulin IgG and IgA response and cytokine level (interleukin-2, interferon-Y) measurement. The results indicated that the nanovaccine administered by intramuscular route produced better humoral as well as cellular responses and potential carriers for antigen delivery at single dose administration via intramuscular route. Copyright © 2018 Elsevier B.V. All rights reserved.

Exploiting the pliability and lateral mobility of Pickering emulsion for enhanced vaccination

NASA Astrophysics Data System (ADS)

Xia, Yufei; Wu, Jie; Wei, Wei; Du, Yiqun; Wan, Tao; Ma, Xiaowei; An, Wenqi; Guo, Aiying; Miao, Chunyu; Yue, Hua; Li, Shuoguo; Cao, Xuetao; Su, Zhiguo; Ma, Guanghui

2018-02-01

A major challenge in vaccine formulations is the stimulation of both the humoral and cellular immune response for well-defined antigens with high efficacy and safety. Adjuvant research has focused on developing particulate carriers to model the sizes, shapes and compositions of microbes or diseased cells, but not antigen fluidity and pliability. Here, we develop Pickering emulsions--that is, particle-stabilized emulsions that retain the force-dependent deformability and lateral mobility of presented antigens while displaying high biosafety and antigen-loading capabilities. Compared with solid particles and conventional surfactant-stabilized emulsions, the optimized Pickering emulsions enhance the recruitment, antigen uptake and activation of antigen-presenting cells, potently stimulating both humoral and cellular adaptive responses, and thus increasing the survival of mice upon lethal challenge. The pliability and lateral mobility of antigen-loaded Pickering emulsions may provide a facile, effective, safe and broadly applicable strategy to enhance adaptive immunity against infections and diseases.

3D confocal Raman imaging of oil-rich emulsion from enzyme-assisted aqueous extraction of extruded soybean powder.

PubMed

Wu, Longkun; Wang, Limin; Qi, Baokun; Zhang, Xiaonan; Chen, Fusheng; Li, Yang; Sui, Xiaonan; Jiang, Lianzhou

2018-05-30

The understanding of the structure morphology of oil-rich emulsion from enzyme-assisted extraction processing (EAEP) was a critical step to break the oil-rich emulsion structure in order to recover oil. Albeit EAEP method has been applied as an alternative way to conventional solvent extraction method, the structure morphology of oil-rich emulsion was still unclear. The current study aimed to investigate the structure morphology of oil-rich emulsion from EAEP using 3D confocal Raman imaging technique. With increasing the enzymatic hydrolysis duration from 1 to 3 h, the stability of oil-rich emulsion was decreased as visualized in the 3D confocal Raman images that the protein and oil were mixed together. The subsequent Raman spectrum analysis further revealed that the decreased stability of oil-rich emulsion was due to the protein aggregations via SS bonds or protein-lipid interactions. The conformational transfer in protein indicated the formation of a compact structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultra-High Pressure Homogenization enhances physicochemical properties of soy protein isolate-stabilized emulsions.

PubMed

Fernández-Ávila, C; Escriu, R; Trujillo, A J

2015-09-01

The effect of Ultra-High Pressure Homogenization (UHPH, 100-300MPa) on the physicochemical properties of oil-in-water emulsions prepared with 4.0% (w/v) of soy protein isolate (SPI) and soybean oil (10 and 20%, v/v) was studied and compared to emulsions treated by conventional homogenization (CH, 15MPa). CH emulsions were prepared with non-heated and heated (95°C for 15min) SPI dispersions. Emulsions were characterized by particle size determination with laser diffraction, rheological properties using a rotational rheometer by applying measurements of flow curve and by transmission electron microscopy. The variation on particle size and creaming was assessed by Turbiscan® analysis, and visual observation of the emulsions was also carried out. UHPH emulsions showed much smaller d 3.2 values and greater physical stability than CH emulsions. The thermal treatment of SPI prior CH process did not improve physical stability properties. In addition, emulsions containing 20% of oil exhibited greater physical stability compared to emulsions containing 10% of oil. Particularly, UHPH emulsions treated at 100 and 200MPa with 20% of oil were the most stable due to low particle size values (d 3.2 and Span), greater viscosity and partial protein denaturation. These results address the physical stability improvement of protein isolate-stabilized emulsions by using the emerging UHPH technology. Copyright © 2015 Elsevier Ltd. All rights reserved.

Controlled assembly of nanoparticle structures: spherical and toroidal superlattices and nanoparticle-coated polymeric beads.

PubMed

Isojima, Tatsushi; Suh, Su Kyung; Vander Sande, John B; Hatton, T Alan

2009-07-21

The emulsion droplet solvent evaporation method has been used to prepare nanoclusters of monodisperse magnetite nanoparticles of varying morphologies depending on the temperature and rate of solvent evaporation and on the composition (solvent, presence of polymer, nanoparticle concentration, etc.) of the emulsion droplets. In the absence of a polymer, and with increasing solvent evaporation temperatures, the nanoparticles formed single- or multidomain crystalline superlattices, amorphous spherical aggregates, or toroidal clusters, as determined by the energetics and dynamics of the solvent evaporation process. When polymers that are incompatible with the nanoparticle coatings were included in the emulsion formulation, monolayer- and multilayer-coated polymer beads and partially coated Janus beads were prepared; the nanoparticles were expelled by the polymer as its concentration increased on evaporation of the solvent and accumulated on the surfaces of the beads in a well-ordered structure. The precise number of nanoparticle layers depended on the polymer/magnetic nanoparticle ratio in the oil droplet phase parent emulsion. The magnetic nanoparticle superstructures responded to the application of a modest magnetic field by forming regular chains with alignment of nonuniform structures (e.g., toroids and Janus beads) that are in accord with theoretical predictions and with observations in other systems.

Reconstructing color images of astronomical objects using black and white spectroscopic emulsions

NASA Technical Reports Server (NTRS)

Dufour, R. I.; Martins, D. H.

1976-01-01

A color photograph of the peculiar elliptical galaxy NGC 5128 (Centaurus A) has been reconstructed from three Kodak 103a emulsion type photographs by projecting positives of the three B&W plates through appropriate filters onto a conventional color film. The resulting photograph shows color balance and latitude characteristics superior to color photographs of similar astronomical objects made with commercially available conventional color film. Similar results have been obtained for color reconstructed photographs of the Large and Small Magellanic Clouds. These and other results suggest that these projection-reconstruction techniques can be used to obtain high-quality color photographs of astronomical objects which overcome many of the problems associated with the use of conventional color film for the long exposures required in astronomy.

Manufacture of poly(methyl methacrylate) microspheres using membrane emulsification

PubMed Central

Bux, Jaiyana; Manga, Mohamed S.; Hunter, Timothy N.

2016-01-01

Accurate control of particle size at relatively narrow polydispersity remains a key challenge in the production of synthetic polymer particles at scale. A cross-flow membrane emulsification (XME) technique was used here in the preparation of poly(methyl methacrylate) microspheres at a 1–10 l h−1 scale, to demonstrate its application for such a manufacturing challenge. XME technology has previously been shown to provide good control over emulsion droplet sizes with careful choice of the operating conditions. We demonstrate here that, for an appropriate formulation, equivalent control can be gained for a precursor emulsion in a batch suspension polymerization process. We report here the influence of key parameters on the emulsification process; we also demonstrate the close correlation in size between the precursor emulsion and the final polymer particles. Two types of polymer particle were produced in this work: a solid microsphere and an oil-filled matrix microcapsule. This article is part of the themed issue ‘Soft interfacial materials: from fundamentals to formulation’. PMID:27298430

The effect of varying the introduction mode of reactants on electrical, physical and thermal stability properties of polypyrrole synthesized with CTAB

NASA Astrophysics Data System (ADS)

Vahidi, K.; Jalili, Y. Seyed; Salar Elahi, A.

2017-10-01

Electrical and physical properties of conducting polymers are generally enhanced via modifications in the chemical structure of the final product, there appears to be a void in facile physical means to improve the materials' properties without utilizing additives which remain in the final product as impurity. In this research, we presented the effect of altering the introduction method of reactants in emulsion polymerization of PPy with CTAB on the electrical, physical and stability properties of the final product. Three samples were prepared: one via a conventional non-emulsion polymerization method as a reference sample, the second in which the reactants were added simultaneously and the goal sample in which the monomer/surfactant mixture was allowed to be stirred separately then it was added dropwise to the oxidant solution. UV-vis, FTIR, 4-point Van Derr Paw probe, FESEM and contact angle measurements were used to investigate optical, electrical, physical, heat stability and solubility properties of the samples. The results indicate that since in the final sample a higher portion of the reaction occurred on the hydrophobic interior of the micelles, the final material had a lower number of structural and chemical defects which leads to higher conjugation lengths and thus higher properties such as a 9-fold difference in conductivity and improved solubility and thermal stability. The novelty of this work lies in the simplicity of the alterations that have been made, both in terms of optimization of the synthetic route which had been thoroughly investigated and also in terms of the differences that our work poses compared to that of the others; namely: the parameters have been thoroughly studied and analyzed but not the method of addition as in our experiments the sequence of addition and the method of addition of the reactants were altered to observe their effect on the physical and the electronic properties which has led to the conclusion that in case of drop-wise addition, a larger portion of the reaction occurs inside the micelles hence giving rise to inhibition of the defect-producing chemical bonds which is supported by the analysis in our investigations.

Preparation of small bio-compatible microspheres

NASA Technical Reports Server (NTRS)

Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Dreyer, William J. (Inventor)

1979-01-01

Small, round, bio-compatible microspheres capable of covalently bonding proteins and having a uniform diameter below about 3500 A are prepared by substantially instantaneously initiating polymerization of an aqueous emulsion containing no more than 35% total monomer including an acrylic monomer substituted with a covalently bondable group such a hydroxyl, amino or carboxyl and a minor amount of a cross-linking agent.

Preparation of silica-coated poly(styrene-co-4-vinylpyridine) particles and hollow particles.

PubMed

Zou, Hua; Wu, Shishan; Shen, Jian

2008-09-16

This paper presents a novel method for preparation of polymer-silica colloidal nanocomposites based on emulsion polymerization and subsequent sol-gel nanocoating process. The polystyrene latex particles bearing basic groups on their surfaces were successfully synthesized through emulsion polymerization using 4-vinylpyridine (4VP) as a functional comonomer and polyvinylpyrrolidone (PVP) as a surfactant. A series of poly(styrene-co-4-vinylpyridine)/SiO2 nanocomposite particles with smooth or rough core-shell morphology were obtained through the coating process. The poly(styrene-co-4-vinylpyridine) particles could be dissolved subsequently or simultaneously during the sol-gel coating process to form hollow particles. The effects of the amount of 4VP, PVP, NH(4)OH, and tetraethoxysilane (TEOS) on both the nanocomposite particles and hollow particles were investigated. Transmission electron microscopy showed that the morphology of the nanocomposite particles and hollow particles was strongly influenced by the initial feed of the comonomer 4VP and the coupling agent PVP. The conditions to obtain all hollow particles were also studied. Thermogravimetric analysis and energy dispersive X-ray spectroscopy analyses indicated that the interiors of hollow particles were not really "hollow".

Ultrasound assisted synthesis of PANI/ZnMoO4 nanocomposite for simultaneous improvement in anticorrosion, physico-chemical properties and its application in gas sensing.

PubMed

Bhanvase, B A; Darda, N S; Veerkar, N C; Shende, A S; Satpute, S R; Sonawane, S H

2015-05-01

Ultrasound assisted in-situ semi-batch emulsion polymerization has been used for the preparation of polyaniline (PANI) and PANI/ZnMoO4 nanocomposite with different loading of ZnMoO4 (ZM) nanoparticles. ZM nanoparticles were functionalized using Myristic acid (MA) for better compatibility with PANI. The cavitational effects induced due to ultrasonic irradiations have been shown significant enhancement in the dispersion of functionalized ZM nanoparticles into the PANI during ultrasound assisted in-situ emulsion polymerization process. TEM images of PANI/ZM nanocomposite particles give the direct evidence of fine dispersion and encapsulation of MA treated ZM nanoparticles in PANI matrix. The presence of ZM nanoparticles in PANI/ZM nanocomposite shows significant improvement in the mechanical (cross-cut adhesion), thermal, anticorrosion and sensing properties of PANI/ZM nanocomposite/alkyd coatings over PANI/alkyd and neat alkyd resin coating. Fine and uniform dispersion of ZM nanoparticles in PANI matrix using this novel synthesis method (PANI (p-type)/ZM (n-type) hetero-junction) improves LPG sensing ability and minimizes response time to sense LPG significantly compared with neat PANI. Copyright © 2014 Elsevier B.V. All rights reserved.

Localized in situ polymerization on graphene surfaces for stabilized graphene dispersions.

PubMed

Das, Sriya; Wajid, Ahmed S; Shelburne, John L; Liao, Yen-Chih; Green, Micah J

2011-06-01

We demonstrate a novel in situ polymerization technique to develop localized polymer coatings on the surface of dispersed pristine graphene sheets. Graphene sheets show great promise as strong, conductive fillers in polymer nanocomposites; however, difficulties in dispersion quality and interfacial strength between filler and matrix have been a persistent problem for graphene-based nanocomposites, particularly for pristine graphene. With this in mind, a physisorbed polymer layer is used to stabilize graphene sheets in solution. To create this protective layer, we formed an organic microenvironment around dispersed graphene sheets in surfactant solutions, and created a nylon 6, 10 or nylon 6, 6 coating via interfacial polymerization. Technique lies at the intersection of emulsion and admicellar polymerization; a similar technique was originally developed to protect luminescent properties of carbon nanotubes in solution. These coated graphene dispersions are aggregation-resistant and may be reversibly redispersed in water even after freeze-drying. The coated graphene holds promise for a number of applications, including multifunctional graphene-polymer nanocomposites. © 2011 American Chemical Society

Traversing the Skin Barrier with Nano-emulsions.

PubMed

Burger, Cornel; Shahzad, Yasser; Brummer, Alicia; Gerber, Minja; du Plessis, Jeanetta

2017-01-01

In recent years, colloidal delivery systems based on nano-emulsion are gaining popularity; being used for encapsulation and delivery of many drugs. This review therefore aims at summarizing various methods of nano-emulsion formulation and their use as a topical and transdermal delivery vehicle for a number of active pharmaceutical ingredients from different pharmacological classes. This article represents a systematic review of nano-emulsions for topical and transdermal drug delivery. A vast literature was searched and critically analysed. Nano-emulsions are thermokinetically stable dispersion systems, which have been used in topical and transdermal delivery of a number of pharmaceutically active compounds. Nano-emulsions have a narrow droplet size range with tuneable surface properties, which make them an ideal delivery vehicle. Nanoemulsions have a number of advantages over conventional emulsions, including easy preparation using various low and high energy methods, optical transparency, high solubilisation capacity, high stability to droplet aggregation and the ability to penetrate the skin; thus allowing the transdermal delivery of drugs. This review indicated that nano-emulsions are promising vehicle for entrapping various drugs and are suitable for traversing the skin barrier for systemic effects. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Interconnected Porous Polymers with Tunable Pore Throat Size Prepared via Pickering High Internal Phase Emulsions.

PubMed

Xu, Hongyun; Zheng, Xianhua; Huang, Yifei; Wang, Haitao; Du, Qiangguo

2016-01-12

Interconnected macroporous polymers were prepared by copolymerizing methyl acrylate (MA) via Pickering high internal phase emulsion (HIPE) templates with modified silica particles. The pore structure of the obtained polymer foams was observed by field-emission scanning electron microscopy (FE-SEM). Gas permeability was characterized to evaluate the interconnectivity of macroporous polymers. The polymerization shrinkage of continuous phase tends to form open pores while the solid particles surrounding the droplets act as barriers to produce closed pores. These two conflicting factors are crucial in determining the interconnectivity of macroporous polymers. Thus, poly-Pickering HIPEs with high permeability and well-defined pore structure can be achieved by tuning the MA content, the internal phase fraction, and the content of modified silica particles.

Closed-Loop Multitarget Optimization for Discovery of New Emulsion Polymerization Recipes

PubMed Central

2015-01-01

Self-optimization of chemical reactions enables faster optimization of reaction conditions or discovery of molecules with required target properties. The technology of self-optimization has been expanded to discovery of new process recipes for manufacture of complex functional products. A new machine-learning algorithm, specifically designed for multiobjective target optimization with an explicit aim to minimize the number of “expensive” experiments, guides the discovery process. This “black-box” approach assumes no a priori knowledge of chemical system and hence particularly suited to rapid development of processes to manufacture specialist low-volume, high-value products. The approach was demonstrated in discovery of process recipes for a semibatch emulsion copolymerization, targeting a specific particle size and full conversion. PMID:26435638

Emulsion stability measurements by single electrode capacitance probe (SeCaP) technology

NASA Astrophysics Data System (ADS)

Schüller, R. B.; Løkra, S.; Salas-Bringas, C.; Egelandsdal, B.; Engebretsen, B.

2008-08-01

This paper describes a new and novel method for the determination of the stability of emulsions. The method is based on the single electrode capacitance technology (SeCaP). A measuring system consisting of eight individual measuring cells, each with a volume of approximately 10 ml, is described in detail. The system has been tested on an emulsion system based on whey proteins (WPC80), oil and water. Xanthan was added to modify the emulsion stability. The results show that the new measuring system is able to quantify the stability of the emulsion in terms of a differential variable. The whole separation process is observed much faster in the SeCaP system than in a conventional separation column. The complete separation process observed visually over 30 h is seen in less than 1.4 h in the SeCaP system.

A microscopy method for scanning transmission electron microscopy imaging of the antibacterial activity of polymeric nanoparticles on a biofilm with an ionic liquid.

PubMed

Takahashi, Chisato; Muto, Shunsuke; Yamamoto, Hiromitsu

2017-08-01

In this study, we developed a scanning transmission electron microscopy (STEM) method for imaging the antibacterial activity of organic polymeric nanoparticles (NPs) toward biofilms formed by Staphylococcus epidermidis bacterial cells, for optimizing NPs to treat biofilm infections. The combination of sample preparation method using a hydrophilic ionic liquid (IL) and STEM observation using the cooling holder eliminates the need for specialized equipment and techniques for biological sample preparation. The annular dark-field STEM results indicated that the two types of biodegradable poly-(DL-lactide-co-glycolide) (PLGA) NPs: PLGA modified with chitosan (CS), and clarithromycin (CAM)-loaded + CS-modified PLGA, prepared by emulsion solvent diffusion exhibited different antibacterial activities in nanoscale. To confirm damage to the sample during STEM observation, we observed the PLGA NPs and the biofilm treated with PLGA NPs by both the conventional method and the newly developed method. The optimized method allows microstructure of the biofilm treated with PLGA NPs to be maintained for 25 min at a current flow of 40 pA. The developed simple sample preparation method would be helpful to understand the interaction of drugs with target materials. In addition, this technique could contribute to the visualization of other deformable composite materials at the nanoscale level. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1432-1437, 2017. © 2016 Wiley Periodicals, Inc.

A new type of polymeric heavy metal complexing precipitant used as fishery disinfectant and antiparasitic drug

NASA Astrophysics Data System (ADS)

Liu, Y. C.; Zhang, A. N.; Wang, X. B.; Xu, J.; Zeng, X. H.; Wang, H. M.

2017-08-01

This paper presents a technique to produce a new kind of fishery drug that is water emulsion suspending agent containing polymeric calcium-iron-dithiocarbamate with heavy metal complexing precipitate ability, good disinfection and auxiliary insecticidal efficacy. The product has good dispersion, high efficiency and low toxicity, as well as no pollution and no harmful residues. It not only can be used in the pond waters and ornamental waters, but also can meet the high requirements of the aquaculture waters. There is non-pollutant emission in the production, which is a green environment-friendly technique without three waste discharges. This technology belongs to the ecological and environmental protection.

Design and Synthesis of Multigraft Copolymer Thermoplastic Elastomers: Superelastomers

DOE PAGES

Wang, Huiqun; Lu, Wei; Wang, Weiyu; ...

2017-09-28

Thermoplastic elastomers (TPEs) have been widely studied because of their recyclability, good processibility, low production cost, and unique performance. The building of graft-type architectures can greatly improve mechanical properties of TPEs. This review focuses on the advances in different approaches to synthesize multigraft copolymer TPEs. Anionic polymerization techniques allow for the synthesis of well-defined macromolecular structures and compositions, with great control over the molecular weight, polydispersity, branch spacing, number of branch points, and branch point functionality. Progress in emulsion polymerization offers potential approaches to commercialize these types of materials with low production cost via simple operations. Moreover, the use ofmore » multigraft architecturesprovides a solution to the limited elongational properties of all-acrylic TPEs, which can greatly expand their potential application range. The combination of different polymerization techniques, the introduction of new chemical compositions, and the incorporation of sustainable sources are expected to be further investigated in this area in coming years.« less

Synthesis and self-assembly of amphiphilic polymeric microparticles.

PubMed

Dendukuri, Dhananjay; Hatton, T Alan; Doyle, Patrick S

2007-04-10

We report the synthesis and self-assembly of amphiphilic, nonspherical, polymeric microparticles. Wedge-shaped particles bearing segregated hydrophilic and hydrophobic sections were synthesized in a microfludic channel by polymerizing across laminar coflowing streams of hydrophilic and hydrophobic polymers using continuous flow lithography (CFL). Particle monodispersity was characterized by measuring both the size of the particles formed and the extent of amphiphilicity. The coefficient of variation (COV) was found to be less than 2.5% in all measured dimensions. Particle structure was further characterized by measuring the curvature of the interface between the sections and the extent of cross-linking using FTIR spectroscopy. The amphiphilic particles were allowed to self-assemble in water or at water-oil interfaces. In water, the geometry of the particles enabled the formation of micelle-like structures, while in emulsions, the particles migrated to the oil-water interface and oriented themselves to minimize their surface energy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Huiqun; Lu, Wei; Wang, Weiyu

Thermoplastic elastomers (TPEs) have been widely studied because of their recyclability, good processibility, low production cost, and unique performance. The building of graft-type architectures can greatly improve mechanical properties of TPEs. This review focuses on the advances in different approaches to synthesize multigraft copolymer TPEs. Anionic polymerization techniques allow for the synthesis of well-defined macromolecular structures and compositions, with great control over the molecular weight, polydispersity, branch spacing, number of branch points, and branch point functionality. Progress in emulsion polymerization offers potential approaches to commercialize these types of materials with low production cost via simple operations. Moreover, the use ofmore » multigraft architecturesprovides a solution to the limited elongational properties of all-acrylic TPEs, which can greatly expand their potential application range. The combination of different polymerization techniques, the introduction of new chemical compositions, and the incorporation of sustainable sources are expected to be further investigated in this area in coming years.« less

Radiation induced graft copolymerization of methyl methacrylate onto chrome-tanned pig skins

NASA Astrophysics Data System (ADS)

Pietrucha, K.; Pȩkala, W.; Kroh, J.

Graft copolymerization of methyl methacrylate (MMA) onto chrome-tanned pig skins was carried out by the irradiation with 60Co ?-rays. The grafted polymethyl methacrylate (PMMA) chains were isolated by acid hydrolysis of the collagen backbone in order to characterize the graft copolymers. Proof of grafting was obtained through the detection of amino acid endgroups in the isolated grafts by reaction with ninhydrin. The grafting yield of MMA in aqueous emulsion was found to be higher than that for pure MMA and MMA in acetone. The degree of grafting increases with increasing monomer concentration in emulsion and reaches maximum at radiation dose ca 15 kGy. The yield of grafting is very high - ca 90% of monomer converts into copolymer and only 10% is converted into homopolymer. The present paper reports the physical properties of chrome-tanned pig skins after graft polymerization with MMA in emulsion. Modified leathers are more resistant against water absorption and abrasion in comparison with unmodified ones. They have more uniform structure over the whole surface, greater thickness and stiffness. The results reported seem to indicate that MMA may be used in the production of shoe upper and sole leathers. The mechanism of some of the processes occuring during radiation grafting of MMA in water emulsion on tanned leathers has been also suggested and discussed.

Molecularly imprinted polymer microspheres prepared by Pickering emulsion polymerization for selective solid-phase extraction of eight bisphenols from human urine samples.

PubMed

Yang, Jiajia; Li, Yun; Wang, Jincheng; Sun, Xiaoli; Cao, Rong; Sun, Hao; Huang, Chaonan; Chen, Jiping

2015-05-04

The bisphenol A (BPA) imprinted polymer microspheres were prepared by simple Pickering emulsion polymerization. Compared to traditional bulk polymerization, both high yields of polymer and good control of particle sizes were achieved. The characterization results of scanning electron microscopy and nitrogen adsorption-desorption measurements showed that the obtained molecularly imprinted polymer microsphere (MIPMS) particles possessed regular spherical shape, narrow diameter distribution (30-60 μm), a specific surface area (S(BET)) of 281.26 m(2) g(-1) and a total pore volume (V(t)) of 0.459 cm(3) g(-1). Good specific adsorption capacity for BPA was obtained in the sorption experiment and good class selectivity for BPA and its seven structural analogs (bisphenol F, bisphenol B, bisphenol E, bisphenol AF, bisphenol S, bisphenol AP and bisphenol Z) was demonstrated by the chromatographic evaluation experiment. The MIPMS as solid-phase extraction (SPE) packing material was then evaluated for extraction and clean-up of these bisphenols (BPs) from human urine samples. An accurate and sensitive analytical method based on the MIPMS-SPE coupled with HPLC-DAD has been successfully established for simultaneous determination of eight BPs from human urine samples with detection limits of 1.2-2.2 ng mL(-1). The recoveries of BPs for urine samples at two spiking levels (100 and 500 ng mL(-1) for each BP) were in the range of 81.3-106.7% with RSD values below 8.3%. Copyright © 2015 Elsevier B.V. All rights reserved.

Fish oil lipid emulsions and immune response: what clinicians need to know.

PubMed

Waitzberg, Dan Linetzky; Torrinhas, Raquel Susana

2009-01-01

Current evidence indicates that omega-3 polyunsaturated fatty acids (PUFAs), particularly eicosapentaenoic acid and docosahexaenoic acid found in fish oil, can prevent the development of inflammatory diseases by affecting different steps of the immune response. The capacity of omega-3 PUFAs to modulate synthesis of eicosanoids, activity of nuclear receptor and nuclear transcription factors, and production of resolvins may also mitigate inflammatory processes already present. Parenteral infusion of omega-3 PUFAs is advantageous, particularly in severely ill patients, because the fatty acids are rapidly incorporated by cells. In addition, when fatty acids are given parenterally, there are no losses from digestion and absorption as there are with enteral infusion. Recently, lipid emulsions enriched with omega-3 fish oil have been introduced as a component of parenteral nutrition. Currently, there is one lipid emulsion that contains only fish oil; it is infused together with conventionally used lipid emulsions. Other commercially available lipid emulsions contain fish oil in a fat mixture; one contains 10% fish oil and another 15% fish oil. Relevant experimental and clinical data from studies evaluating fish oil lipid emulsions are discussed in the present review. Administration of fish oil lipid emulsion, when compared with soybean oil lipid emulsion (rich in omega-6 PUFA), decreases the length of hospital and intensive care unit stay in surgical patients.

A new scanning system for alpha decay events as calibration sources for range-energy relation in nuclear emulsion

NASA Astrophysics Data System (ADS)

Yoshida, J.; Kinbara, S.; Mishina, A.; Nakazawa, K.; Soe, M. K.; Theint, A. M. M.; Tint, K. T.

2017-03-01

A new scanning system named "Vertex picker" has been developed to rapid collect alpha decay events, which are calibration sources for the range-energy relation in nuclear emulsion. A computer-controlled optical microscope scans emulsion layers exhaustively, and a high-speed and high-resolution camera takes their micrographs. A dedicated image processing picks out vertex-like shapes. Practical operations of alpha decay search were demonstrated by emulsion sheets of the KEK-PS E373 experiment. Alpha decays of nearly 28 events were detected in eye-check work on a PC monitor per hour. This yield is nearly 20 times more effective than that by the conventional eye-scan method. The speed and quality is acceptable for the coming new experiment, J-PARC E07.

Nucleation of polystyrene latex particles in the presence of gamma-methacryloxypropyltrimethoxysilane: functionalized silica particles.

PubMed

Bourgeat-Lami, Elodie; Insulaire, Mickaelle; Reculusa, Stéphane; Perro, Adeline; Ravaine, Serge; Duguet, Etienne

2006-02-01

Silica/polystyrene nanocomposite particles with different morphologies were synthesized through emulsion polymerization of styrene in the presence of silica particles previously modified by gamma-methacryloxypropyltrimethoxysilane (MPS). Grafting of the silane molecule was performed by direct addition of MPS to the aqueous silica suspension in the presence of an anionic surfactant under basic conditions. The MPS grafting density on the silica surface was determined using the depletion method and plotted against the initial MPS concentration. The influence of the MPS grafting density, the silica particles size and concentration and the nature of the surfactant on the polymerization kinetics and the particles morphology was investigated. When the polymerization was performed in the presence of an anionic surfactant, transmission electron microscopy images showed the formation of polymer spheres around silica for MPS grafting densities lower than typically 1 micromole x m(-2) while the conversion versus time curves indicated a strong acceleration effect under such conditions. In contrast, polymerizations performed in the presence of a larger amount of MPS moieties or in the presence of a non ionic emulsifier resulted in the formation of "excentered" core-shell morphologies and lower polymerization rates. The paper identifies the parameters that allow to control particles morphology and polymerization kinetics and describes the mechanism of formation of the nanocomposite colloids.

Microchannel emulsification: A promising technique towards encapsulation of functional compounds.

PubMed

Khalid, Nauman; Kobayashi, Isao; Neves, Marcos A; Uemura, Kunihiko; Nakajima, Mitsutoshi

2017-06-13

This review provides an overview of microchannel emulsification (MCE) for production of functional monodispersed emulsion droplets. The main emphasis has been put on functional bioactives encapsulation using grooved-type and straight-through microchannel array plates. MCE successfully encapsulates the bioactives like β-carotene, oleuropein, γ-oryzanol, β-sitosterol, L-ascorbic acid and ascorbic acid derivatives, vitamin D and quercetin. These bioactives were encapsulated in a variety of delivery systems like simple and multiple emulsions, polymeric particles, microgels, solid lipid particles and functional vesicles. The droplet generation process in MCE is based upon spontaneous transformation of interfaces rather than high energy shear stress systems. The scale-up of MCE can increase the productivity of monodispersed droplets >100 L h -1 and makes it a promising tool at industrial level.

Recent advances in engineering microparticles and their nascent utilization in biomedical delivery and diagnostic applications.

PubMed

Choi, Andrew; Seo, Kyoung Duck; Kim, Do Wan; Kim, Bum Chang; Kim, Dong Sung

2017-02-14

Complex microparticles (MPs) bearing unique characteristics such as well-tailored sizes, various morphologies, and multi-compartments have been attempted to be produced by many researchers in the past decades. However, a conventionally used method of fabricating MPs, emulsion polymerization, has a limitation in achieving the aforementioned characteristics and several approaches such as the microfluidics-assisted (droplet-based microfluidics and flow lithography-based microfluidics), electrohydrodynamics (EHD)-based, centrifugation-based, and template-based methods have been recently suggested to overcome this limitation. The outstanding features of complex MPs engineered through these suggested methods have provided new opportunities for MPs to be applied in a wider range of applications including cell carriers, drug delivery agents, active pigments for display, microsensors, interface stabilizers, and catalyst substrates. Overall, the engineered MPs expose their potential particularly in the field of biomedical engineering as the increased complexity in the engineered MPs fulfills well the requirements of the high-end applications. This review outlines the current trends of newly developed techniques used for engineered MPs fabrication and focuses on the current state of engineered MPs in biomedical applications.

Effect of Monomer Solubility on the Evolution of Copolymer Morphology during Polymerization-Induced Self-Assembly in Aqueous Solution

PubMed Central

2017-01-01

Polymerization-induced self-assembly (PISA) has become a widely used technique for the rational design of diblock copolymer nano-objects in concentrated aqueous solution. Depending on the specific PISA formulation, reversible addition–fragmentation chain transfer (RAFT) aqueous dispersion polymerization typically provides straightforward access to either spheres, worms, or vesicles. In contrast, RAFT aqueous emulsion polymerization formulations often lead to just kinetically-trapped spheres. This limitation is currently not understood, and only a few empirical exceptions have been reported in the literature. In the present work, the effect of monomer solubility on copolymer morphology is explored for an aqueous PISA formulation. Using 2-hydroxybutyl methacrylate (aqueous solubility = 20 g dm–3 at 70 °C) instead of benzyl methacrylate (0.40 g dm–3 at 70 °C) for the core-forming block allows access to an unusual “monkey nut” copolymer morphology over a relatively narrow range of target degrees of polymerization when using a poly(methacrylic acid) RAFT agent at pH 5. These new anisotropic nanoparticles have been characterized by transmission electron microscopy, dynamic light scattering, aqueous electrophoresis, shear-induced polarized light imaging (SIPLI), and small-angle X-ray scattering. PMID:28216792

PLGA nanoparticles from nano-emulsion templating as imaging agents: Versatile technology to obtain nanoparticles loaded with fluorescent dyes.

PubMed

Fornaguera, C; Feiner-Gracia, N; Calderó, G; García-Celma, M J; Solans, C

2016-11-01

The interest in polymeric nanoparticles as imaging systems for biomedical applications has increased notably in the last decades. In this work, PLGA nanoparticles, prepared from nano-emulsion templating, have been used to prepare novel fluorescent imaging agents. Two model fluorescent dyes were chosen and dissolved in the oil phase of the nano-emulsions together with PLGA. Nano-emulsions were prepared by the phase inversion composition (PIC) low-energy method. Fluorescent dye-loaded nanoparticles were obtained by solvent evaporation of nano-emulsion templates. PLGA nanoparticles loaded with the fluorescent dyes showed hydrodynamic radii lower than 40nm; markedly lower than those reported in previous studies. The small nanoparticle size was attributed to the nano-emulsification strategy used. PLGA nanoparticles showed negative surface charge and enough stability to be used for biomedical imaging purposes. Encapsulation efficiencies were higher than 99%, which was also attributed to the nano-emulsification approach as well as to the low solubility of the dyes in the aqueous component. Release kinetics of both fluorescent dyes from the nanoparticle dispersions was pH-independent and sustained. These results indicate that the dyes could remain encapsulated enough time to reach any organ and that the decrease of the pH produced during cell internalization by the endocytic route would not affect their release. Therefore, it can be assumed that these nanoparticles are appropriate as systemic imaging agents. In addition, in vitro toxicity tests showed that nanoparticles are non-cytotoxic. Consequently, it can be concluded that the preparation of PLGA nanoparticles from nano-emulsion templating represents a very versatile technology that enables obtaining biocompatible, biodegradable and safe imaging agents suitable for biomedical purposes. Copyright © 2016 Elsevier B.V. All rights reserved.

Viscosity of the oil-in-water Pickering emulsion stabilized by surfactant-polymer and nanoparticle-surfactant-polymer system

NASA Astrophysics Data System (ADS)

Sharma, Tushar; Kumar, G. Suresh; Chon, Bo Hyun; Sangwai, Jitendra S.

2014-11-01

Information on the viscosity of Pickering emulsion is required for their successful application in upstream oil and gas industry to understand their stability at extreme environment. In this work, a novel formulation of oil-in-water (o/w) Pickering emulsion stabilized using nanoparticle-surfactant-polymer (polyacrylamide) system as formulated in our earlier work (Sharma et al., Journal of Industrial and Engineering Chemistry, 2014) is investigated for rheological stability at high pressure and high temperature (HPHT) conditions using a controlled-strain rheometer. The nanoparticle (SiO2 and clay) concentration is varied from 1.0 to 5.0 wt%. The results are compared with the rheological behavior of simple o/w emulsion stabilized by surfactant-polymer system. Both the emulsions exhibit non-Newtonian shear thinning behavior. A positive shift in this behavior is observed for surfactant-polymer stabilized emulsion at high pressure conditions. Yield stress is observed to increase with pressure for surfactant-polymer emulsion. In addition, increase in temperature has an adverse effect on the viscosity of emulsion stabilized by surfactant-polymer system. In case of nanoparticle-surfactant-polymer stabilized o/w emulsion system, the viscosity and yield stress are predominantly constant for varying pressure and temperature conditions. The viscosity data for both o/w emulsion systems are fitted by the Herschel-Bulkley model and found to be satisfactory. In general, the study indicates that the Pickering emulsion stabilized by nanoparticle-surfactant-polymer system shows improved and stable rheological properties as compared to conventional emulsion stabilized by surfactant-polymer system indicating their successful application for HPHT environment in upstream oil and gas industry.

Use of hydrophobically modified inulin for the preparation of polymethyl methacrylate/polybutyl acrylate latex particles using a semicontinuous reactor.

PubMed

Obiols-Rabasa, M; Ramos, J; Forcada, J; Esquena, J; Solans, C; Levecke, B; Booten, K; Tadros, Tharwat F

2010-06-01

The seeded semicontinuous emulsion copolymerization of methyl methacrylate (MMA) and butyl acrylate (BuA) stabilized with a graft polymeric surfactant based on inulin, INUTEC SP1, as well as its mixture with sodium lauryl sulfate (SLS) is described. The mixture of SLS and Brij58 (alcohol ethoxylated) and the mixture of SLS and Pluronic P85 (block copolymer PEO-PPO-PEO) are also used as surfactant systems. The addition of methacrylic acid (MAA) or acrylic acid (AA) as comonomers is also studied. Previous results proved this inulin-derivative surfactant, INUTEC SP1, to be very effective on synthesizing latexes using a very low surfactant concentration. The kinetic features of the emulsion polymerization (instantaneous conversion and total conversion) were gravimetrically determined along the reactions. Latex dispersions were characterized by photon correlation spectroscopy (PCS) and transmission electron microscopy (TEM) to obtain the average particle size, the particle size distributions (PSDs) as well as the polydispersity index (PdI). The stability was determined by turbidimetry measurements and expressed in terms of critical coagulation concentration. The results showed that the use of the graft polymeric surfactant allowed obtaining highly stable nanoparticles, at low surfactant concentrations and high solid contents (up to 37 wt %). This is an improvement with respect to previous works, in which a mixture of the graft polymeric surfactant with another surfactant was required to obtain stable nanoparticles with low polydispersity, at high solid content. In the present work, low polydispersity was achieved using INUTEC as the only emulsifier, which was related to the absence of secondary nucleations. When a mixture of INUTEC SP1 and SLS is used, a wider PSD is obtained due to secondary nucleations. Replacing INUTEC SP1 by other nonionic surfactants such as Brij58 or Pluronic P85 leads to an increase of average particle size and wider PSD.

Design of polystyrene latex particles covered with polyoxometalate clusters via multiple covalent bonding

DOE PAGES

Chen, Xinyue; Li, Hui; Yin, Panchao; ...

2015-02-27

In this study, polyoxometalates (POMs) covalently functionalized with methyl methacrylate groups were applied as surfactants in the emulsion polymerization reaction of styrene. Due to the copolymerization of the methyl methacrylate groups and the styrene monomers, the polyoxometalate clusters are covalently grafted onto the surface of polystyrene latex nanoparticles. Finally, such latex particles are fully covered with catalytic POM clusters and might serve as quasi-homogeneous catalysts.

Effect of PLGA as a polymeric emulsifier on preparation of hydrophilic protein-loaded solid lipid nanoparticles.

PubMed

Xie, ShuYu; Wang, SiLiang; Zhao, BaoKai; Han, Chao; Wang, Ming; Zhou, WenZhong

2008-12-01

Most proteins are hydrophilic and poorly encapsulated into the hydrophobic matrix of solid lipid nanoparticles (SLN). To solve this problem, poly (lactic-co-glycolic acid) (PLGA) was utilized as a lipophilic polymeric emulsifier to prepare hydrophilic protein-loaded SLN by w/o/w double emulsion and solvent evaporation techniques. Hydrogenated castor oil (HCO) was used as a lipid matrix and bovine serum albumin (BSA), lysozyme and insulin were used as model proteins to investigate the effect of PLGA on the formulation of the SLN. The results showed that PLGA was essential for the primary w/o emulsification. In addition, the stability of the w/o emulsion, the encapsulation efficiency and loading capacity of the nanoparticles were enhanced with the increase of PLGA concentration. Furthermore, increasing PLGA concentration decreased zeta potential significantly but had no influence on particle size of the SLN. In vitro release study showed that PLGA significantly affected the initial burst release, i.e. the higher the content of PLGA, the lower the burst release. The released proteins maintained their integrity and bioactivity as confirmed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and biological assay. These results demonstrated that PLGA was an effective emulsifier for the preparation of hydrophilic protein-loaded SLN.

Hollow latex particles: synthesis and applications.

PubMed

McDonald, Charles J; Devon, Michael J

2002-12-02

One of the major developments in emulsion polymerization over the last two decades has been the ability to make hollow latex particles. This has contributed many fundamental insights into the synthesis and the development of structure in particles. Hollow latex particles also enhance the performance of industrial coatings and potentially are useful in other technologies such as microencapsulation and controlled release. Ever since the publication of the initial process patents describing these particles, there has been a global R&D effort to extend the synthetic techniques and applications. One prominent synthetic approach to hollow particles is based on osmotic swelling. This dominates the literature, and usually starts with the synthesis of a structured latex particle containing an ionizable core that is subsequently expanded with the addition of base. Fundamental to this approach are a sophisticated control of transport phenomena, chemical reactivity within the particle, and the thermoplastic properties of the polymer shell. Hydrocarbon encapsulation technology has also been employed to make hollow latex particles. One approach involves a dispersed ternary system that balances transport, conversion kinetics, and phase separation variables to achieve the hollow morphology. Other techniques, including the use of blowing agents, are also present in the literature. The broad range of approaches that affords particles with a hollow structure demonstrates the unique flexibility of the emulsion polymerization process.

An Investigation of a Photographic Technique of Measuring High Surface Temperatures

NASA Technical Reports Server (NTRS)

Siviter, James H., Jr.; Strass, H. Kurt

1960-01-01

A photographic method of temperature determination has been developed to measure elevated temperatures of surfaces. The technique presented herein minimizes calibration procedures and permits wide variation in emulsion developing techniques. The present work indicates that the lower limit of applicability is approximately 1,400 F when conventional cameras, emulsions, and moderate exposures are used. The upper limit is determined by the calibration technique and the accuracy required.

Kinetics of successive seeding of monodisperse polystyrene latexes. I - Initiation via potassium persulfate. II - Azo initiators with and without inhibitors

NASA Technical Reports Server (NTRS)

Sudol, E. D.; El-Aasser, M. S.; Vanderhoff, J. W.

1986-01-01

The polymerization kinetics of monodisperse polystyrene latexes with diameters of 1 micron are studied. The monodisperse latexes were prepared by the successive seeding method using 1 mM K2S2O8 with an 8 percent emulsifier surface coverage and 0.5 mM K2S2O8 with a 4 percent emulsifier surface coverage, and the kinetics were measured in a piston/cylinder dialometer. The data reveal that the polymerization rate decreases with increasing particle size; and the surface charge decreases with increasing particle size. The effects of initiators (AIBN and AMBN) and inhibitors (NH24SCN, NaNO2, and hydroquinone) on the product monodispersity and polymerization kinetics of latexes with diameters greater than 1 micron are investigated in a second experiment. It is observed that hydroquinone combined with AMBN are most effective in reducing nucleation without causing flocculation. It is noted that the kinetic transition from emulsion to bulk is complete for a particle size exceeding 1 micron in which the polymerization rate is independent of the particle size.

Effect of polymerization method and fabrication method on occlusal vertical dimension and occlusal contacts of complete-arch prosthesis.

PubMed

Lima, Ana Paula Barbosa; Vitti, Rafael Pino; Amaral, Marina; Neves, Ana Christina Claro; da Silva Concilio, Lais Regiane

2018-04-01

This study evaluated the dimensional stability of a complete-arch prosthesis processed by conventional method in water bath or microwave energy and polymerized by two different curing cycles. Forty maxillary complete-arch prostheses were randomly divided into four groups (n = 10): MW1 - acrylic resin cured by one microwave cycle; MW2 - acrylic resin cured by two microwave cycles: WB1 - conventional acrylic resin polymerized using one curing cycle in a water bath; WB2 - conventional acrylic resin polymerized using two curing cycles in a water bath. For evaluation of dimensional stability, occlusal vertical dimension (OVD) and area of contact points were measured in two different measurement times: before and after the polymerization method. A digital caliper was used for OVD measurement. Occlusal contact registration strips were used between maxillary and mandibular dentures to measure the contact points. The images were measured using the software IpWin32, and the differences before and after the polymerization methods were calculated. The data were statistically analyzed using the one-way ANOVA and Tukey test (α = .05). he results demonstrated significant statistical differences for OVD between different measurement times for all groups. MW1 presented the highest OVD values, while WB2 had the lowest OVD values ( P <.05). No statistical differences were found for area of contact points among the groups ( P =.7150). The conventional acrylic resin polymerized using two curing cycles in a water bath led to less difference in OVD of complete-arch prosthesis.

Hydrophobin-nanofibrillated cellulose stabilized emulsions for encapsulation and release of BCS class II drugs.

PubMed

Paukkonen, Heli; Ukkonen, Anni; Szilvay, Geza; Yliperttula, Marjo; Laaksonen, Timo

2017-03-30

The purpose of this study was to construct biopolymer-based oil-in-water emulsion formulations for encapsulation and release of poorly water soluble model compounds naproxen and ibuprofen. Class II hydrophobin protein HFBII from Trichoderma reesei was used as a surfactant to stabilize the oil/water interfaces of the emulsion droplets in the continuous aqueous phase. Nanofibrillated cellulose (NFC) was used as a viscosity modifier to further stabilize the emulsions and encapsulate protein coated oil droplets in NFC fiber network. The potential of both native and oxidized NFC were studied for this purpose. Various emulsion formulations were prepared and the abilities of different formulations to control the drug release rate of naproxen and ibuprofen, used as model compounds, were evaluated. The optimal formulation for sustained drug release consisted of 0.01% of drug, 0.1% HFBII, 0.15% oxidized NFC, 10% soybean oil and 90% water phase. By comparison, the use of native NFC in combination with HFBII resulted in an immediate drug release for both of the compounds. The results indicate that these NFC originated biopolymers are suitable for pharmaceutical emulsion formulations. The native and oxidized NFC grades can be used as emulsion stabilizers in sustained and immediate drug release applications. Furthermore, stabilization of the emulsions was achieved with low concentrations of both HFBII and NFC, which may be an advantage when compared to surfactant concentrations of conventional excipients traditionally used in pharmaceutical emulsion formulations. Copyright © 2017 Elsevier B.V. All rights reserved.

Thermal tuning the reversible optical band gap of self-assembled polystyrene photonic crystals

NASA Astrophysics Data System (ADS)

Vakili Tahami, S. H.; Pourmahdian, S.; Shirkavand Hadavand, B.; Azizi, Z. S.; Tehranchi, M. M.

2016-11-01

Nano-sized polymeric colloidal particles could undergo self-organization into three-dimensional structures to produce desired optical properties. In this research, a facile emulsifier-free emulsion polymerization method was employed to synthesize highly mono-disperse sub-micron polystyrene colloids. A high quality photonic crystal (PhC) structure was prepared by colloidal polystyrene. The reversible thermal tuning effect on photonic band gap position as well as the attenuation of the band gap was investigated in detail. The position of PBG can be tuned from 420 nm to 400 nm by varying the temperature of the PhC structure, reversibly. This reversible effect provides a reconfigurable PhC structure which could be used as thermo-responsive shape memory polymers.

Incorporation of iodine in polymeric microparticles and emulsions

NASA Astrophysics Data System (ADS)

Kolontaeva, Olga A.; Khokhlova, Anastasia R.; Markina, Natalia E.; Markin, Alexey V.; Burmistrova, Natalia A.

2016-04-01

Application of different methods for formation of microcontainers containing iodine is proposed in this paper. Two types of microcontainers: microemulsions and microparticles have been investigated, conditions and methods for obtaining microcontainers were optimized. Microparticles were formed by layer-by-layer method with cores of calcium carbonate (CaCO3) as templates. Incorporation of complexes of iodine with polymers (chitosan, starch, polyvinyl alcohol) into core, shell and hollow capsules was investigated and loadings of microparticles with iodine were estimated. It was found that the complex of iodine with chitosan adsorbed at CaCO3 core is the most stable under physiological conditions and its value of loading can be 450 μg of I2 per 1 g of CaCO3. Moreover, chitosan was chosen as a ligand because of its biocompatibility and biodegradability as well as very low toxicity while its complex with iodine is very stable. A small amount of microparticles containing a iodine-chitosan complex can be used for prolonged release of iodine in the human body since iodine daily intake for adults is around 100 μg. "Oil-in-water" emulsions were prepared by ultrasonication of iodinated oils (sunflower and linseed) with sodium laurilsulfate (SLS) as surfactant solution. At optimal conditions, the homogenous emulsions remained stable for weeks, with total content of iodine in such emulsion being up to 1% (w/w). The oil:SLS ratio was equal to 1:10 (w/w), optimal duration and power of ultrasound exposure were 1.5 min and 7 W, correspondingly. Favorable application of iodized linseed oil for emulsion preparation with suitable oil microdroplets size was proved.

Parameters for Stable Water-in-Oil Lipiodol Emulsion for Liver Trans-Arterial Chemo-Eembolization.

PubMed

Deschamps, F; Moine, L; Isoardo, T; Tselikas, L; Paci, A; Mir, L M; Huang, N; Fattal, E; de Baère, T

2017-12-01

Water-in-oil type and stability are important properties for Lipiodol emulsions during conventional trans-arterial chemo-embolization. Our purpose is to evaluate the influence of 3 technical parameters on those properties. The Lipiodol emulsions have been formulated by repetitive back-and-forth pumping of two 10-ml syringes through a 3-way stopcock. Three parameters were compared: Lipiodol/doxorubicin ratio (2/1 vs. 3/1), doxorubicin concentration (10 vs. 20 mg/ml) and speed of incorporation of doxorubicin in Lipiodol (bolus vs. incremental vs. continuous). The percentage of water-in-oil emulsion obtained and the duration until complete coalescence (stability) for water-in-oil emulsions were, respectively, evaluated with the drop-test and static light scattering technique (Turbiscan). Among the 48 emulsions formulated, 32 emulsions (67%) were water-in-oil. The percentage of water-in-oil emulsions obtained was significantly higher for incremental (94%) and for continuous (100%) injections compared to bolus injection (6%) of doxorubicin. Emulsion type was neither influenced by Lipiodol/doxorubicin ratio nor by doxorubicin concentration. The mean stability of water-in-oil emulsions was 215 ± 257 min. The emulsions stability was significantly longer when formulated using continuous compared to incremental injection (326 ± 309 vs. 96 ± 101 min, p = 0.018) and using 3/1 compared to 2/1 ratio of Lipiodol/doxorubicin (372 ± 276 vs. 47 ± 43 min, p = <0.0001). Stability was not influenced by the doxorubicin concentration. The continuous and incremental injections of doxorubicin in the Lipiodol result in highly predictable water-in-oil emulsion type. It also demonstrates a significant increase in stability compared to bolus injection. Higher ratio of Lipiodol/doxorubicin is a critical parameter for emulsion stability too.

Parenteral structured triglyceride emulsion improves nitrogen balance and is cleared faster from the blood in moderately catabolic patients.

PubMed

Kruimel, J W; Naber, T H; van der Vliet, J A; Carneheim, C; Katan, M B; Jansen, J B

2001-01-01

Most postoperative patients lose net protein mass, which reflects loss of muscle tissue and organ function. Perioperative parenteral nutrition may reduce the loss of protein, but in general, with conventional lipid emulsions a waste of protein still remains. We compared the effects on nitrogen balance of an emulsion containing structured triglycerides, a new type of synthesized triglycerides, with an emulsion of a physical mixture of medium- and long-chain triglycerides as part of parenteral feeding in moderately catabolic patients. The first 5 days after placement of an aortic prosthesis patients received total parenteral nutrition (TPN) providing 0.2 g of nitrogen per kg body weight per day; energy requirement was calculated using Harris and Benedict's equation, adding 300 kcal per day for activity. Twelve patients were treated with the structured triglyceride emulsion and 13 patients with the emulsion of the physical mixture of medium- and long-chain triglycerides. The design was a randomized, double-blind parallel study. In the patients who completed the study, the mean cumulative nitrogen balance over the first 5 postoperative days was -8+/-2 g in 10 patients on the structured triglyceride emulsion and -21+/-4 g in 9 patients on the emulsion of the physical mixture of medium- and long-chain triglycerides; the mean difference was 13 g of nitrogen (95% confidence interval 4 to 22, p = .015) in favor of the structured triglyceride emulsion. On the first postoperative day serum triglyceride and plasma medium-chain free fatty acid levels increased less during infusion of the structured triglyceride emulsion than with the physical mixture emulsion. The parenteral structured triglyceride emulsion improves the nitrogen balance and is cleared faster from the blood, compared with the emulsion of the physical mixture of medium- and long-chain triglycerides, in moderately catabolic patients.

Quantitative imaging of aggregated emulsions.

PubMed

Penfold, Robert; Watson, Andrew D; Mackie, Alan R; Hibberd, David J

2006-02-28

Noise reduction, restoration, and segmentation methods are developed for the quantitative structural analysis in three dimensions of aggregated oil-in-water emulsion systems imaged by fluorescence confocal laser scanning microscopy. Mindful of typical industrial formulations, the methods are demonstrated for concentrated (30% volume fraction) and polydisperse emulsions. Following a regularized deconvolution step using an analytic optical transfer function and appropriate binary thresholding, novel application of the Euclidean distance map provides effective discrimination of closely clustered emulsion droplets with size variation over at least 1 order of magnitude. The a priori assumption of spherical nonintersecting objects provides crucial information to combat the ill-posed inverse problem presented by locating individual particles. Position coordinates and size estimates are recovered with sufficient precision to permit quantitative study of static geometrical features. In particular, aggregate morphology is characterized by a novel void distribution measure based on the generalized Apollonius problem. This is also compared with conventional Voronoi/Delauney analysis.

Control of lipid oxidation by nonmigratory active packaging films prepared by photoinitiated graft polymerization.

PubMed

Tian, Fang; Decker, Eric A; Goddard, Julie M

2012-08-08

Transition metal-promoted oxidation impacts the quality, shelf life, and nutrition of many packaged foods. Metal-chelating active packaging therefore offers a means to protect foods against oxidation. Herein, we report the development and characterization of nonmigratory metal-chelating active packaging. To prepare the films, carboxylic acids were grafted onto the surfaces of polypropylene films by photoinitiated graft polymerization of acrylic acid. Attenuated total reflectance/Fourier transform infrared spectroscopy, contact angle, scanning electron microscopy, and iron-chelating assay were used to characterize film properties. Graft polymerization yielded a carboxylic acid density of 68.67 ± 9.99 nmol per cm(2) film, with ferrous iron-chelating activity of 71.07 ± 12.95 nmol per cm(2). The functionalized films extended the lag phase of lipid oxidation in a soybean oil-in-water emulsion system from 2 to 9 days. The application of such nonmigratory active packaging films represents a promising approach to reduce additive use while maintaining food quality.

Pore Structure and Fluoride Ion Adsorption Characteristics of Zr (IV) Surface-Immobilized Resin Prepared Using Polystyrene as a Porogen

NASA Astrophysics Data System (ADS)

Mizuki, Hidenobu; Ito, Yudai; Harada, Hisashi; Uezu, Kazuya

Zr(IV) surface-immobilized resins for removal of fluoride ion were prepared by surface template polymerization using polystyrene as a porogen. At polymerization, polystyrene was added in order to increase mesopores (2-50 nm) and macropore (>50 nm) with large macropores (around 300 nm) formed with internal aqueous phase of W⁄O emulsion. The pore structure of Zr(IV) surface-immobilized resins was evaluated by measuring specific surface area, pore volume, and pore size distribution with volumetric adsorption measurement instrument and mercury porosimeter. The adsorption isotherms were well fitted by Langmuir equation. The removal of fluoride was also carried out with column method. Zr(IV) surface-immobilized resins, using 10 g⁄L polystyrene in toluene at polymerization, possessed higher volume of not only mesopores and macropores but also large macropores. Furethermore, by adding the polystyrene with smaller molecular size, the pore volume of mesopores, macropores and large macropores was significantly increased, and the fluoride ion adsorption capacity and the column utilization also increased.

Synthesis of berberine loaded polymeric nanoparticles by central composite design

NASA Astrophysics Data System (ADS)

Mehra, Meenakshi; Sheorain, Jyoti; Kumari, Santosh

2016-04-01

Berberine is an isoquinoline alkaloid which is extracted from bark and roots of Berberis vulgaris plant. It has been used in ayurvedic medicine as it possess antimicrobial, antidiabetic, anticancer, antioxidant properties etc. But poor solubility of berberine leads to poor stability and bioavailability in medical formulations decreasing its efficacy. Hence nanoformulations of berberine can help in removing the limiting factors of alkaloid enhancing its utilization in pharmaceutical industry. Sodium alginate polymer was used to encapsulate berberine within nanoparticles by emulsion solvent evaporation method using tween 80 as a surfactant. Two factors and three level in central composite design was used to study the formulation. The optimized formulation (1% v/v of Tween 80 and 0.01% w/v of sodium alginate) of polymeric nanoparticles was taken for further evaluations. The size of synthesized nanoparticles was found to be 71.18 nm by particle size analysis (PSA). The berberine loaded polymeric nanoparticles showed better antibacterial activity compared to aqueous solution of berberine by well diffusion assay.

With medium-chain triglycerides, higher and faster oxygen radical production by stimulated polymorphonuclear leukocytes occurs.

PubMed

Kruimel, J W; Naber, A H; Curfs, J H; Wenker, M A; Jansen, J B

2000-01-01

Parenteral lipid emulsions are suspected of suppressing the immune function. However, study results are contradictory and mainly concern the conventional long-chain triglyceride emulsions. Polymorphonuclear leukocytes were preincubated with parenteral lipid emulsions. The influence of the lipid emulsions on the production of oxygen radicals by these stimulated leukocytes was studied by measuring chemiluminescence. Three different parenteral lipid emulsions were tested: long-chain triglycerides, a physical mixture of medium- and long-chain triglycerides, and structured triglycerides. Structured triglycerides consist of triglycerides where the medium- and long-chain fatty acids are attached to the same glycerol molecule. Stimulated polymorphonuclear leukocytes preincubated with the physical mixture of medium- and long-chain triglycerides showed higher levels of oxygen radicals (p < .005) and faster production of oxygen radicals (p < .005) compared with polymorphonuclear leukocytes preincubated with long-chain triglycerides or structured triglycerides. Additional studies indicated that differences in results of various lipid emulsions were not caused by differences in emulsifier. The overall production of oxygen radicals was significantly lower after preincubation with the three lipid emulsions compared with controls without lipid emulsion. A physical mixture of medium- and long-chain triglycerides induced faster production of oxygen radicals, resulting in higher levels of oxygen radicals, compared with long-chain triglycerides or structured triglycerides. This can be detrimental in cases where oxygen radicals play either a pathogenic role or a beneficial one, such as when rapid phagocytosis and killing of bacteria is needed. The observed lower production of oxygen radicals by polymorphonuclear leukocytes in the presence of parenteral lipid emulsions may result in immunosuppression by these lipids.

Retention of denture bases fabricated by three different processing techniques – An in vivo study

PubMed Central

Chalapathi Kumar, V. H.; Surapaneni, Hemchand; Ravikiran, V.; Chandra, B. Sarat; Balusu, Srilatha; Reddy, V. Naveen

2016-01-01

Aim: Distortion due to Polymerization shrinkage compromises the retention. To evaluate the amount of retention of denture bases fabricated by conventional, anchorized, and injection molding polymerization techniques. Materials and Methods: Ten completely edentulous patients were selected, impressions were made, and master cast obtained was duplicated to fabricate denture bases by three polymerization techniques. Loop was attached to the finished denture bases to estimate the force required to dislodge them by retention apparatus. Readings were subjected to nonparametric Friedman two-way analysis of variance followed by Bonferroni correction methods and Wilcoxon matched-pairs signed-ranks test. Results: Denture bases fabricated by injection molding (3740 g), anchorized techniques (2913 g) recorded greater retention values than conventional technique (2468 g). Significant difference was seen between these techniques. Conclusions: Denture bases obtained by injection molding polymerization technique exhibited maximum retention, followed by anchorized technique, and least retention was seen in conventional molding technique. PMID:27382542

Characteristics of low polymerization shrinkage flowable resin composites in newly-developed cavity base materials for bulk filling technique.

PubMed

Nitta, Keiko; Nomoto, Rie; Tsubota, Yuji; Tsuchikawa, Masuji; Hayakawa, Tohru

2017-11-29

The purpose of this study was to evaluate polymerization shrinkage and other physical properties of newly-developed cavity base materials for bulk filling technique, with the brand name BULK BASE (BBS). Polymerization shrinkage was measured according to ISO/FDIS 17304. BBS showed the significantly lowest polymerization shrinkage and significantly higher depth of cure than conventional flowable resin composites (p<0.05). The Knoop hardness, flexural strength and elastic modulus of that were significantly lower than conventional flowable resin composites (p<0.05). BBS had the significantly greatest filler content (p<0.05). SEM images of the surface showed failure of fillers. The lowest polymerization shrinkage was due to the incorporation of a new type of low shrinkage monomer, which has urethane moieties. There were no clear correlations between inorganic filler contents and polymerization shrinkage, flexural strength and elastic modulus. In conclusion, the low polymerization shrinkage of BBS will be useful for cavity treatment in dental clinics.

Morphological study of polymethyl methacrylate microcapsules filled with self-healing agents

NASA Astrophysics Data System (ADS)

Ahangaran, Fatemeh; Hayaty, Mehran; Navarchian, Amir H.

2017-03-01

Polymethyl methacrylate (PMMA) microcapsules filled with epoxy prepolymer, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, and pentaerythritol tetrakis (3-mercaptopropionate) as healing agents have been prepared separately through internal phase separation method for self-healing purposes. PMMA with two different molecular weights (M bar1 = 36,000 g/mol and M bar2 = 550,000 g/mol) were used with two types of different emulsifiers (ionic and polymeric) to prepare microcapsules. The morphology of healing agent microcapsules was investigated using field emission scanning electron microscopy (FESEM). It was found that PMMA microcapsules separately filled with epoxy and amine had core-shell morphologies with smooth surfaces. The mercaptan/PMMA particles exhibited core-shell and acorn-shape morphologies. The surface morphology of mercaptan microcapsules changed from holed to plain in different emulsion systems. The spreading coefficient (S) of phases in the prepared emulsion systems were calculated from interfacial tension (σ) and contact angle (θ) measurements. The theoretical equilibrium morphology of PMMA microcapsules was predicted according to spreading coefficient values of phases in emulsion systems. It was also found that the surface morphology of PMMA microcapsules depended strongly on the nature of the core, molecular weight of PMMA, type and concentration of emulsifier.

Effects of poly(lactic-co-glycolic acid) on preparation and characteristics of plasmid DNA-loaded solid lipid nanoparticles.

PubMed

Zhu, L; Xie, S; Dong, Z; Wang, X; Wang, Y; Zhou, W

2011-09-01

Poly(lactic-co-glycolic acid) (PLGA) was used as a polymeric emulsifier to encapsulate plasmid DNA into hydrogenated castor oil (HCO)-solid lipid nanoparticles (SLN) by w/o/w double emulsion and solvent evaporation techniques. The effects of PLGA on the preparation, characteristics and transfection efficiency of DNA-loaded SLN were studied. The results showed that PLGA was essential to form the primary w/o emulsion and the stability of the emulsion was enhanced with the increase of PLGA content. DNA-loaded SLN were spherical with smooth surfaces. The SLN had a negative charge in weak acid and alkaline environment but acquired a positive charge in acidic pH and the cationisation capacity of the SLN increased with the increase of PLGA/HCO ratio. Agarose gel electrophoresis demonstrated that the majority of the DNA maintained its structural integrity after preparation and being extracted or released from DNA-loaded SLN. When PLGA/HCO ratio increased from 5 to 15%, the encapsulation efficiency, loading capacity and transfection efficiency of the nanoparticles increased significantly, whereas the changes of particle size and polydispersity index were insignificant. Cytotoxicity study in cell culture demonstrated that the SLN was not toxic.

Co-polymerization of methyl methacrylate and styrene via surfactant-free emulsion polymerization, as a potential material for photonic crystal application

NASA Astrophysics Data System (ADS)

Kassim, Syara; Zahari, Siti Balqis; Tahrin, Rabiatul Addawiyah Azwa; Harun, Noor Aniza

2017-09-01

Photonic crystals are being the great interest of researcher to studies due to a variety of potential application for the interaction of light including the solar cells, optical sensors and paints. In order to evaluate the fabrication of photonic crystals thin film, a free-emulsifier emulsion copolymerization of styrene and methyl methacrylate was carried out. By using the self -assembly approach, this method offers the opportunity to produce crystalline polymer sphere in more ease operation, low cost and environmental friendly. The influences of the mixing ratio of monomer and amount of initiators were studied. In advance, the presence of styrene as co-monomer had improved the thermal degradation of polymer methyl methacrylate. While in changing the mixing ratio of styrene and methyl methacrylate resulted in particle size of the sphere. The size of polymer particles slightly increased on increasing volume of styrene monomer ratio. This occurred because the properties of styrene in water where it sparingly soluble and lead to coagulation of particles. This simple, yet effective method for preparing functional complex 3D structures has the potential to be used generically to fabricate a variety of functional porous 3D structures that could find application not only in new or improved photonic crystal (PC) devices but also in areas such as catalysis, solar cell, separation, fuel cells technology, microelectronics and optoelectronics.

Pharmacological aspects of release from microcapsules - from polymeric multilayers to lipid membranes.

PubMed

Wuytens, Pieter; Parakhonskiy, Bogdan; Yashchenok, Alexey; Winterhalter, Mathias; Skirtach, Andre

2014-10-01

This review is devoted to pharmacological applications of principles of release from capsules to overcome the membrane barrier. Many of these principles were developed in the context of polymeric multilayer capsule membrane modulation, but they are also pertinent to liposomes, polymersomes, capsosomes, particles, emulsion-based carriers and other carriers. We look at these methods from the physical, chemical or biological driving mechanisms point of view. In addition to applicability for carriers in drug delivery, these release methods are significant for another area directly related to pharmacology - modulation of the permeability of the membranes and thus promoting the action of drugs. Emerging technologies, including ionic current monitoring through a lipid membrane on a nanopore, are also highlighted. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preparation and characterization of a magneto-polymeric nanocomposite: Fe 3O 4 nanoparticles in a grafted, cross-linked and plasticized poly(vinyl chloride) matrix

NASA Astrophysics Data System (ADS)

Rodríguez-Fernández, Oliverio S.; Rodríguez-Calzadíaz, C. A.; Yáñez-Flores, Isaura G.; Montemayor, Sagrario M.

In this work two kind of materials: (1) grafted, cross-linked and plasticized poly(vinyl chloride) (PVC) "plastic films" and (2) magnetic plastic films "magneto-polymeric nanocomposites" were prepared. Precursor solutions or "plastisols" used to obtain the plastic films were obtained by mixing PVC (emulsion grade) as polymeric matrix, di(2-ethylhexyl)phthalate (DOP) as plasticizer, a thermal stabilizer based in Ca/Zn salts, and a cross-linking agent, 3-mercaptopropyltrimethoxysilane (MTMS) or 3-aminopropyltriethoxysilane (ATES), at several concentrations. Flexible films were obtained from the plastisols using static casting. The stress-strain behavior and the gel content (determined by Soxhlet extraction with boiling THF) of the flexible films were measured in order to evaluate the effect of the cross-linking agent and their content on the degree of cross-linking. The magneto-polymeric nanocomposites were obtained by mixing the optimum composition of the plastisols (analyzed previously) with magnetite (Fe 3O 4)-based ferrofluid and DOP. Later, flexible films were obtained by static casting of the plastisol/ferrofluid systems. The magnetic films were characterized by the above-mentioned techniques and X-ray diffraction, vibrating sample magnetometry and thermogravimetrical analysis.

Nonequilibrium stabilization of an RNA/protein droplet emulsion by nuclear actin

NASA Astrophysics Data System (ADS)

Brangwynne, Clifford

2013-03-01

Actin plays a structural role in the cytoplasm. However, actin takes on new functions and structures in the nucleus that are poorly understood. The nuclei of the large oocytes of the frog X. laevisspecifically accumulate actin to reach high concentrations; however, it remains unclear if this actin polymerizes into a network, and what, if any, structural role such an actin network might play. Here, we use microrheological and confocal imaging techniques to probe the local architecture and mechanics of the nucleus. Our data show that actin forms a weak network that spatially organizes the nucleus by kinetically stabilizing embedded liquid-like RNA/protein bodies which are important for cell growth. In actin-disrupted nuclei this RNA/protein droplet emulsion is destabilized leading to homotypic coalescence into single large droplets. Our data provide intriguing new insights into why large cell nuclei require an actin-based structural scaffold.

Preparation of an Adhesive in Emulsion for Maxillofacial Prosthetic

PubMed Central

Sánchez-García, Judith A.; Ortega, Alejandra; Barceló-Santana, Federico H.; Palacios-Alquisira, Joaquín

2010-01-01

Maxillofacial prostheses is a dental medicine specialty aimed at restoring anatomical facial defects caused by cancer, trauma or congenital malformations through an artificial device, which is commonly attached to the skin with the help of an adhesive. The purpose of our research was to develop a pressure-sensitive adhesive (PSA) based on acrylic monomers, characterizing and determining its drying kinetics, that is to say the time it takes to lose 50 to 90% of its moisture. The adhesive synthesis was realized by means of emulsion polymerization; the composition of formulations was: (AA-MMA-EA) and (AA-MMA-2EHA) with different molar ratios. The formulation based on (AA-MMA-2EHA) with 50 w% of solids, presented good adhesive properties such as tack, bond strength, and short drying time. We propose this formulation as a PSA, because it offers an alternative for systemically compromised patients, by less irritation compared to organic solvent-based adhesives. PMID:21152308

Asphaltene dispersants as demulsification aids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manek, M.B.

1995-11-01

Destabilization of petroleum asphaltenes may cause a multitude of problems in crude oil recovery and production. One major problem is their agglomeration at the water-oil interface of crude oil emulsions. Once agglomeration occurs, destabilized asphaltenes can form a thick pad in the dehydration equipment, which significantly reduces the demulsification rate. Certain polymeric dispersants increase asphaltene solubilization in hydrocarbon media, and when used in conjunction with emulsion breakers, facilitate the demulsification process. Two case studies are presented that demonstrate how asphaltene dispersants can efficiently inhibit pad formation and help reduce demulsifier dosage. Criteria for dispersant application and selection are discussed, whichmore » include the application of a novel laboratory technique to assess asphaltene stabilization in the crude oil. The technique monitors asphaltene agglomeration while undergoing titration with an incompatible solvent (precipitant). The method was used to evaluate stabilization of asphaltenes in the crude oil and to screen asphaltene dispersants.« less

Molecular Design of Squalene/Squalane Countertypes via the Controlled Oligomerization of Isoprene and Evaluation of Vaccine Adjuvant Applications.

PubMed

Adlington, Kevin; El Harfi, Jaouad; Li, Jianing; Carmichael, Kim; Guderian, Jeffrey A; Fox, Christopher B; Irvine, Derek J

2016-01-11

The potential to replace shark-derived squalene in vaccine adjuvant applications with synthetic squalene/poly(isoprene) oligomers, synthesized by the controlled oligomerization of isoprene is demonstrated. Following on from our previous work regarding the synthesis of poly(isoprene) oligomers, we demonstrate the ability to tune the molecular weight of the synthetic poly(isoprene) material beyond that of natural squalene, while retaining a final backbone structure that contained a minimum of 75% of 1,4 addition product and an acceptable polydispersity. The synthesis was successfully scaled from the 2 g to the 40 g scale both in the bulk (i.e., solvent free) and with the aid of additional solvent by utilizing catalytic chain transfer polymerization (CCTP) as the control method, such that the target molecular weight, acceptable dispersity levels, and the desired level of 1,4 addition in the backbone structure and an acceptable yield (∼60%) are achieved. Moreover, the stability and in vitro bioactivity of nanoemulsion adjuvant formulations manufactured with the synthetic poly(isoprene) material are evaluated in comparison to emulsions made with shark-derived squalene. Emulsions containing the synthetic poly(isoprene) achieved smaller particle size and equivalent or enhanced bioactivity (stimulation of cytokine production in human whole blood) compared to corresponding shark squalene emulsions. However, as opposed to the shark squalene-based emulsions, the poly(isoprene) emulsions demonstrated reduced long-term size stability and induced hemolysis at high concentrations. Finally, we demonstrate that the synthetic oligomeric poly(isoprene) material could successfully be hydrogenated such that >95% of the double bonds were successfully removed to give a representative poly(isoprene)-derived squalane mimic.

Dynamics of Unjammed Emulsions

NASA Astrophysics Data System (ADS)

Guerra, Rodrigo; Kodger, Thomas; Weitz, David

2014-03-01

Light scattering and NMR densitometry measurements of quiescent emulsions have shown that amorphous packings of soft, repulsive droplets unjam at osmotic pressures 105 times larger than the typical droplet thermal energy density: 3kB/T 4 πR3. This transition corresponds to the pressure at which the thermal fluctuations of individual droplet positions match the yield strain of the packing and drive the fluidization of the material. We use confocal microscopy to investigate the microscopic dynamics of this fluid-like phase and find them to be fundamentally different from those of conventional glass-forming liquids; cage-breaking dynamics are not evident from droplet mean squared displacements and the effective viscosity of the emulsion, though 105 larger than the background fluid, appears largely insensitive to the confining pressure.

[Effect of techniques of composite resin insertion and polymerization on microleakage and microhardness].

PubMed

Amaral, Cristiane Mariote; Castro, Ana Karina Barbieri Bedran de; Pimenta, Luiz André Freire; Ambrosano, Glaucia Maria Boni

2002-01-01

The aim of this study was to evaluate the influence of techniques of composite resin polymerization and insertion on microleakage and microhardness. One hundred and eighty class II cavities were prepared in bovine teeth and assigned to six groups: G1 - bulk filling + conventional polymerization; G2 - bucco-lingual increments + conventional polymerization; G3 - bulk filling + soft-start polymerization; G4 - bucco-lingual increments + soft-start polymerization; G5 - bulk filling + progressive polymerization; G6 - bucco-lingual increments + progressive polymerization. All cavities were restored with the Z100/Single Bond system (3M). After thermocycling, the samples were immersed in 2% methylene blue dye solution for 4 hours. Half of the samples were embedded in polystyrene resin, and Knoop microhardness was measured. The Kruskal-Wallis test did not reveal statistical differences (p > 0.05) between the polymerization and insertion techniques as to microleakage. Regarding microhardness, the two-way ANOVA and the Tukey test did not reveal statistical differences between the restorative techniques (p > 0.05), but progressive polymerization (G5 and G6) was associated with smaller Knoop microhardness values (p < 0.05): G = 144.11; G2 = 143.89; G3 = 141.14; G4 = 142.79; G5 = 132.15; G6 = 131.67. It was concluded that the evaluated polymerization and insertion techniques did not affect marginal microleakage, but a decrease in microhardness occurred when progressive polymerization was carried out.

Water-in-Water Emulsion Based Synthesis of Hydrogel Nanospheres with Tunable Release Kinetics

NASA Astrophysics Data System (ADS)

Aydın, Derya; Kızılel, Seda

2017-07-01

Poly(ethylene glycol) (PEG) micro/nanospheres have several unique advantages as polymer based drug delivery systems (DDS) such as tunable size, large surface area to volume ratio, and colloidal stability. Emulsification is one of the widely used methods for facile synthesis of micro/nanospheres. Two-phase aqueous system based on polymer-polymer immiscibility is a novel approach for preparation of water-in-water (w/w) emulsions. This method is promising for the synthesis of PEG micro/nanospheres for biological systems, since the emulsion is aqueous and do not require organic solvents or surfactants. Here, we report the synthesis of nano-scale PEG hydrogel particles using w/w emulsions using phase separation of dextran and PEG prepolymer. Dynamic light scattering (DLS) and scaning electron microscopy (SEM) results demonstrated that nano-scale hydrogel spheres could be obtained with this approach. We investigated the release kinetics of a model drug, pregabalin (PGB) from PEG nanospheres and demonstrated the influence of polymerization conditions on loading and release of the drug as well as the morphology and size distribution of PEG nanospheres. The experimental drug release data was fitted to a stretched exponential function which suggested high correlation with experimental results to predict half-time and drug release rates from the model equation. The biocompatibility of nanospheres on human dermal fibroblasts using cell-survival assay suggested that PEG nanospheres with altered concentrations are non-toxic, and can be considered for controlled drug/molecule delivery.

Anti-Inflammatory and Anti-Fibrotic Profile of Fish Oil Emulsions Used in Parenteral Nutrition-Associated Liver Disease

PubMed Central

Pastor-Clerigues, Alfonso; Marti-Bonmati, Ezequiel; Milara, Javier; Almudever, Patricia; Cortijo, Julio

2014-01-01

Home parenteral nutrition (PN) is associated with many complications including severe hepatobiliary dysfunction. Commercial ω-6 fatty acid-soybean based-lipid emulsions in PN may mediate long term PN associate liver disease (PNALD) whereas ω-3-fish oil parenteral emulsions have shown to reverse PNALD in children. However, its clinical effectiveness in adults has been scarcely reported. In this work, we study the role of soybean and fish oil lipid commercial emulsions on inflammatory and profibrotic liver markers in adults with long term PNALD and in in vitro cellular models. Inflammatory and profibrotic markers were measured in serum of ten adults with long term PNALD and in culture supernatants of monocytes. Liver epithelial to mesenchymal transition (EMT) was induced by transforming growth factor beta 1 (TGFβ1) to evaluate in vitro liver fibrosis. Omegaven®, a 100% fish oil commercial emulsion, was infused during four months in two patients with severe long term PNALD reversing, at the first month, the inflammatory, profibrotic and clinical parameters of PNALD. The effect was maintained during the treatment course but impaired when conventional lipid emulsions were reintroduced. The other patients under chronic soybean oil-based PN showed elevated inflammatory and profibrotic parameters. In vitro human monocytes stimulated with lipopolysaccharide induced a strong inflammatory response that was suppressed by Omegaven®, but increased by soybean emulsions. In other experiments, TGFβ1 induced EMT that was suppressed by Omegaven® and enhanced by soybean oil lipid emulsions. Omegaven® improves clinical, anti-inflammatory and anti-fibrotic parameters in adults with long-term home PNALD. PMID:25502575

Interfacial rheology of model particles at liquid interfaces and its relation to (bicontinuous) Pickering emulsions

NASA Astrophysics Data System (ADS)

Thijssen, J. H. J.; Vermant, J.

2018-01-01

Interface-dominated materials are commonly encountered in both science and technology, and typical examples include foams and emulsions. Conventionally stabilised by surfactants, emulsions can also be stabilised by micron-sized particles. These so-called Pickering-Ramsden (PR) emulsions have received substantial interest, as they are model arrested systems, rather ubiquitous in industry and promising templates for advanced materials. The mechanical properties of the particle-laden liquid-liquid interface, probed via interfacial rheology, have been shown to play an important role in the formation and stability of PR emulsions. However, the morphological processes which control the formation of emulsions and foams in mixing devices, such as deformation, break-up, and coalescence, are complex and diverse, making it difficult to identify the precise role of the interfacial rheological properties. Interestingly, the role of interfacial rheology in the stability of bicontinuous PR emulsions (bijels) has been virtually unexplored, even though the phase separation process which leads to the formation of these systems is relatively simple and the interfacial deformation processes can be better conceptualised. Hence, the aims of this topical review are twofold. First, we review the existing literature on the interfacial rheology of particle-laden liquid interfaces in rheometrical flows, focussing mainly on model latex suspensions consisting of polystyrene particles carrying sulfate groups, which have been most extensively studied to date. The goal of this part of the review is to identify the generic features of the rheology of such systems. Secondly, we will discuss the relevance of these results to the formation and stability of PR emulsions and bijels.

Shear Driven Synthesis of Polymeric Micro- and Nanomaterials

NASA Astrophysics Data System (ADS)

Tian, Tian

Polymeric micro- and nanomaterials play a significant role in various current and emerging technologies. A liquid shear based method was developed to fabricate a wide range of polymeric materials, which include fibers, sheets, ribbons, rods and spheres in a scalable, cost-effective and simple way. During the process, droplet shearing, droplet deformation, droplet breaking up and polymer precipitation occur simultaneously. The size and morphology of the resultant structures are determined by the dominating process which is further controlled by the experimental parameters including polymer concentration, polymer molecular weight and antisolvent concentration. Among all of these structures, nanofibers have attracted the latest research interest due to the unique properties. Current leading fiber production approaches in the market possess certain drawbacks. For example, the throughput of electrospinning is limited to around 2.5 kg/hr and the diameter of fiber produced by wet spinning cannot be below micrometer while melt spinning is only applicable to melt-processable polymers. The breakthrough of our liquid shear driven technique for fiber synthesis is that it produces fibers with diameter from 200 nm to several micrometers from a wide range of liquid- processable polymers with high commercial yield (up to 12 kg/hr). Thus in Chapter 2, the optimum parameters range for fiber formation is established and the effects of those parameters on fiber size are investigated. In the original liquid shear method, medium with high viscosity is needed to exert strong shear stress on the droplet and to stretch the droplets to long strand. However, the viscous medium complicates the post sample washing procedure and introduces the potential slippery danger in the working area. Thus a non-viscous medium shearing method is developed in Chapter 3 and it is the first time proposed that the synthesis of PLA or PS nanofibers can be completed in the aqueous ethanol medium. Colloid science usually categorizes emulsion as oil in water (O/W) and water in oil (W/O) dispersions. Oil in oil emulsion can also be formulated from the immiscible organic liquid pairs. Using the phase separation in the PS-cyclohexane system, the emulsion are formed under continuous shearing while the continuous phase is solvent-rich and the disperse phase is polymer-rich. By shearing the emulsions, the fibers sizes are reduced around 10X due to the smaller initial polymer droplet size. The fiber sizes are further reduced to 100 nm which enhances the competitive advantages of liquid shear technique. Controlled drug release combines the advantages of increased therapeutic efficacy, reduced toxicity and lower administration frequency. By dispersing model drugs in the spinning polymer solution, these drugs are successfully encapsulated inside the biodegradable matrix and the encapsulation efficiency is modulated by polymer concentration and fiber size while the release profile of the drug is determined by the degradation rate of the polymer matrix.

Diesel engine fuel consumption and emission analysis using steam generated non-surfactant water-in-diesel emulsion fuel

NASA Astrophysics Data System (ADS)

Avianto Sugeng, Dhani; Zahari, Mohamad Fathur Hafeezat Mohd; Muhsin Ithnin, Ahmad; Jazair Yahya, Wira

2017-10-01

Efforts in making water in diesel emulsion (W/D) with the absence of surfactant have been developed to address the issues of long-term stability and the dependence on surfactants. This paper discusses an alternative formation method of a non-surfactant W/D, e.g. by steam condensation. By injecting steam into a batch of colder diesel fuel, fine water droplets are formed and suspended in the fuel forming an emulsion. The droplets are confirmed to be in the size range of hundreds of nanometers. The emissions of NOx is reduced by a maximum of 71%, whereas the CO and UHC emissions are increased by maximum respectively 180% and a surprising 517%. Not less interesting is the lower BSFC which was measured at a maximum reduction of 18.4%. These results on emission analysis together with the brake specific fuel consumption confirm this method to resemble the combustion behaviour of a conventional emulsion fuel of lower NOx and BSFC, yet higher CO and UHC

Experimental Studies of Diestrol-Micro Emulsion Fuel in a Direct Injection Compression Ignition Engine under Varying Injection Pressures and Timings

NASA Astrophysics Data System (ADS)

Kannan, Gopal Radhakrishnan

2018-02-01

The research work on biodiesel becomes more attractive in the context of limited availability of petroleum fuels and rapid increase of harmful emissions from diesel engine using conventional fossil fuels. The present investigation has dealt with the influence of biodiesel-diesel-ethanol (diestrol) water micro emulsion fuel (B60D20E20M) on the performance, emission and combustion characteristics of a diesel engine under different injection pressure and timing. The results revealed that the maximum brake thermal efficiency of 32.4% was observed at an injection pressure of 260 bar and injection timing of 25.5°bTDC. In comparison with diesel, micro emulsion fuel showed reduction in carbon monoxide (CO) and total hydrocarbon (THC) by 40 and 24%, respectively. Further, micro emulsion fuel decreased nitric oxide (NO) emission and smoke emission by 7 and 20.7%, while the carbon dioxide (CO2) emission is similar to that of diesel.

Three-dimensional molecular mapping of a multiple emulsion by means of CARS microscopy.

PubMed

Meyer, Tobias; Akimov, Denis; Tarcea, Nicolae; Chatzipapadopoulos, Susana; Muschiolik, Gerald; Kobow, Jens; Schmitt, Michael; Popp, Jürgen

2008-02-07

Multiple emulsions consisting of water droplets dispersed in an oil phase containing emulsifier which is emulsified in an outer water phase (W/O/W) are of great interest in pharmacology for developing new drugs, in the nutrition sciences for designing functional food, and in biology as model systems for cell organelles such as liposomes. In the food industry multiple emulsions with high sugar content in the aqueous phase can be used for the production of sweets, because the high sugar content prevents deterioration. However, for these emulsions the refractive indexes of oil and aqueous phase are very similar. This seriously impedes the analysis of these emulsions, e.g., for process monitoring, because microscopic techniques based on transmission or reflection do not provide sufficient contrast. We have characterized the inner dispersed phase of concentrated W/O/W emulsions with the same refractive index of the three phases by micro Raman spectroscopy and investigated the composition and molecular distribution in water-oil-water emulsions by means of three-dimensional laser scanning CARS (coherent anti-Stokes Raman scattering) microscopy. CARS microscopy has been used to study water droplets dispersed in oil droplets at different Raman resonances to visualize different molecular species. Water droplets with a diameter of about 700 nm could clearly be visualized. The advantages of CARS microscopy for studying this particular system are emphasized by comparing this microscopic technique with conventional confocal reflection and transmission microscopies.

Fabricating core (Au)-shell (different stimuli-responsive polymers) nanoparticles via inverse emulsion polymerization: Comparing DOX release behavior in dark room and under NIR lighting.

PubMed

Mazloomi-Rezvani, Mahsa; Salami-Kalajahi, Mehdi; Roghani-Mamaqani, Hossein

2018-06-01

Different core-shell nanoparticles with Au as core and stimuli-responsive polymers such as poly(acrylic acid) (PAA), poly(methacrylic acid) (PMAA), poly(N-isopropylacrylamide) (PNIPAAm), poly(N,N'-methylenebis(acrylamide)) (PMBA), poly(2-hydroxyethyl methacrylate) (PHEMA) and poly((2-dimethylamino)ethyl methacrylate) (PDMAEMA) as shells were fabricated via inverse emulsion polymerization. Dynamic light scattering (DLS) was used to investigate particles sizes and particle size distributions and transmission electron microscopy (TEM) was applied to observe the core-shell structure of Au-polymer nanoparticles. Also, surface charge of all samples was studied by measurement of zeta potentials. Synthesized core-shell nanoparticles were utilized as nanocarriers of DOX as anti-cancer drug and drug release behaviors were investigated in dark room and under irradiation of near-infrared (NIR) light. Results showed that all core-shell samples have particle sizes less than 100 nm with narrow particle size distributions. Moreover, amount of drug loading decreased by increasing zeta potential. In dark room, lower pH resulted in higher cumulative drug release due to better solubility of DOX in acidic media. Also, NIR lighting on DOX-loaded samples led to increasing cumulative drug release significantly. However, DOX-loaded Au-PAA and Au-PMAA showed higher drug release at pH = 7.4 compared to 5.3 under NIR lighting. Copyright © 2018 Elsevier B.V. All rights reserved.

Production of exopolysaccharide from rhizobia with potential biotechnological and bioremediation applications.

PubMed

Castellane, Tereza Cristina Luque; Persona, Michelli Romanoli; Campanharo, João Carlos; de Macedo Lemos, Eliana Gertrudes

2015-03-01

The potential use of rhizobia under controlled fermentation conditions may result in the production of new extracellular polymeric substances (EPS) having novel and superior properties that will open up new areas of industrial applications and thus increase their demand. The production of EPS and the stability of emulsions formed with soybean oil, diesel oil and toluene using different concentrations of purified EPS derived from wild-type and mutant strains of Rhizobium tropici SEMIA 4077 was investigated. The EPS was defined as a heteropolysaccharide composed of six constituent monosaccharides that displayed higher intrinsic viscosity and pseudoplastic non-Newtonian fluid behavior in an aqueous solution. The ratio between the total EPS production and the cellular biomass was 76.70 for the 4077::Z04 mutant strain and only 8.10 for the wild-type strain. The EPS produced by the wild-type R. tropici SEMIA 4077 resulted in more stable emulsions with the tested toluene than xanthan gum, and the emulsification indexes with hydrocarbons and soybean oil were higher than 50%, indicating strong emulsion-stabilizing capacity. These results demonstrate that the EPS of R. tropici strains could be attractive for use in industrial and environmental applications, as it had higher intrinsic viscosity and good emulsification activity. Copyright © 2015 Elsevier B.V. All rights reserved.

Biomimetic Multilayer Nanofibrous Membranes with Elaborated Superwettability for Effective Purification of Emulsified Oily Wastewater.

PubMed

Ge, Jianlong; Jin, Qing; Zong, Dingding; Yu, Jianyong; Ding, Bin

2018-05-09

Creating a porous membrane to effectively separate the emulsified oil-in-water emulsions with energy-saving property is highly desired but remains a challenge. Herein, a multilayer nanofibrous membrane was developed with the inspiration of the natural architectures of earth for gravity-driven water purification. As a result, the obtained biomimetic multilayer nanofibrous membranes exhibited three individual layers with designed functions; they were the inorganic nanofibrous layer to block the serious intrusion of oil to prevent the destructive fouling of the polymeric matrix; the submicron porous layer with designed honeycomb-like cavities to catch the smaller oil droplets and ensures a satisfactory water permeability; and the high porous fibrous substrate with larger pore size provided a template support and allows water to pass through quickly. Consequently, with the cooperation of these three functional layers, the resultant composite membrane possessed superior anti-oil-fouling property and robust oil-in-water emulsion separation performance with good separation efficiency and competitive permeation flux solely under the drive of gravity. The permeation flux of the membrane for the emulsion was up to 5163 L m -2 h -1 with a separation efficiency of 99.5%. We anticipate that our strategy could provide a facile route for developing a new generation of specific membranes for oily wastewater remediation.

Fabrication of advanced particles and particle-based materials assisted by droplet-based microfluidics.

PubMed

Wang, Jing-Tao; Wang, Juan; Han, Jun-Jie

2011-07-04

Recent advances in the fabrication of complex particles and particle-based materials assisted by droplet-based microfluidics are reviewed. Monodisperse particles with expected internal structures, morphologies, and sizes in the range of nanometers to hundreds of micrometers have received a good deal of attention in recent years. Due to the capability of generating monodisperse emulsions and of executing precise control and operations on the suspended droplets inside the microchannels, droplet-based microfluidic devices have become powerful tools for fabricating complex particles with desired properties. Emulsions and multiple-emulsions generated in the microfluidic devices can be composed of a variety of materials including aqueous solutions, gels, polymers and solutions containing functional nanoparticles. They are ideal microreactors or fine templates for synthesizing advanced particles, such as polymer particles, microcapsules, nanocrystals, and photonic crystal clusters or beads by further chemical or physical operations. These particles are promising materials that may be applicable for many fields, such as photonic materials, drug delivery systems, and bio-analysis. From simple to complex, from spherical to nonspherical, from polymerization and reaction crystallization to self-assembly, this review aims to help readers be aware of the many aspects of this field. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanical properties of light-curing composites polymerized with different laboratory photo-curing units.

PubMed

da Silva, Gisele Rodrigues; Simamoto-Júnior, Paulo Cezar; da Mota, Adérito Soares; Soares, Carlos José

2007-03-01

This study aimed to analyze the microhardness (KHN) and diametral tensile strength (DTS) of two hybrid resin composites (TPH Spectrum and Filtek Z250). To this end, the composites were polymerized with six laboratory photo-curing units (LPUs) and the results compared with an alternative polymerization method using conventional halogen light source in conjunction with additional polymerization in an autoclave (15 minutes/100 degrees C). LPUs were used following the manufacturers' instructions. Diametral tensile strength and Knoop hardness tests were conducted for all groups (n=5). Data were statistically compared using ANOVA and Tukey's test (alpha = 0.05). Among the LPUs, the one that provided light curing in conjunction with heat and nitrogen pressure resulted in a significant increase in KHN and DTS of resin composites. Between the resin composites, Filtek Z250 showed higher hardness values than TPH Spectrum. It was concluded that the use of alternative polymerization with conventional light polymerization and autoclave was feasible with a wide implication for the general public in terms of reduced dental treatment cost.

Synthesis of new solid polymer electrolyte and actuator based on PEDOT/NBR/ionic liquid

NASA Astrophysics Data System (ADS)

Cho, M. S.; Seo, H. J.; Nam, J. D.; Choi, H. R.; Koo, J. C.; Lee, Y.

2006-03-01

The conducting polymer actuator was presented. The solid polymer electrolyte based on nitrile rubber (NBR) activated with different ionic liquids was prepared. The three different grades of NBR films were synthesized by emulsion polymerization with different amount of acrylonitrile, 23, 35, and 40 mol. %, respectively. The effect of acrylonitrile content on the ionic conductivity and dielectric constant of solid polymer electrolytes was characterized. A conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), was synthesized on the surface of the NBR layer by using a chemical oxidation polymerization technique, and room temperature ionic liquids (RTIL) based on imidazolium salts, e.g. 1-butyl-3-methyl imidazolium X [where X= BF 4 -, PF 6 -, (CF 3SO II) IIN -], were absorbed into the composite film. The effects of the anion size of the ionic liquids on the displacement of the actuator were examined. The displacement increased with increasing the anion-size of the ionic liquids.

Drug delivery properties of macroporous polystyrene solid foams.

PubMed

Canal, Cristina; Aparicio, Rosa Maria; Vilchez, Alejandro; Esquena, Jordi; García-Celma, Maria José

2012-01-01

Polymeric porous foams have been evaluated as possible new pharmaceutical dosage forms. These materials were obtained by polymerization in the continuous phase of highly concentrated emulsions prepared by the phase inversion temperature method. Their porosity, specific surface and surface topography were characterized, and the incorporation and release of active principles was studied using ketoprofen as model lipophilic molecule. Solid foams with very high pore volume, mainly inside macropores, were obtained by this method. The pore morphology of the materials was characterized, and very rough topography was observed, which contributed to their nearly superhydrophobic properties. These solid foams could be used as delivery systems for active principles with pharmaceutical interest, and in the present work ketoprofen was used as a model lipophilic molecule. Drug incorporation and release was studied from solid foam disks, using different concentrations of the loading solutions, achieving a delayed release with short lag-time.

Biodegradable gelatin-based nanospheres as pH-responsive drug delivery systems

NASA Astrophysics Data System (ADS)

Curcio, Manuela; Altimari, Ilaria; Spizzirri, Umile Gianfranco; Cirillo, Giuseppe; Vittorio, Orazio; Puoci, Francesco; Picci, Nevio; Iemma, Francesca

2013-04-01

Native gelatin, N, N'-ethylenebisacrylamide, and sodium methacrylate were inserted into a spherical crosslinked structure by a solvent-free emulsion polymerization method, in which sunflower seed oil containing different amounts of lecithin was selected as continuous phase. Nanogels were characterized by morphological analysis, particle size distribution, and determination of swelling degree. Different dimensional distributions (100-500 nm) and water affinities were obtained by varying the amount of surfactant in the polymerization feed. Nanogels were non-toxic on human bone marrow mesenchymal stromal cells and enzymatically stable in the gastric tract, with weight losses ranging from 58 to 20 % in pancreatin solution. Release profiles of diclofenac sodium salt from the nanogels were evaluated at different pH and found to depend on crosslinking degree and drug-polymer interactions; while in pancreatin solution, a complete release of the drug was observed. The release mechanism and the diffusional contribution were evaluated by semiempirical equations.

Facile synthesis of hollow Sn-Co@PMMA nanospheres as high performance anodes for lithium-ion batteries via galvanic replacement reaction and in situ polymerization

NASA Astrophysics Data System (ADS)

Yu, Xiaohui; Jiang, Anni; Yang, Hongyan; Meng, Haowen; Dou, Peng; Ma, Daqian; Xu, Xinhua

2015-08-01

Polymethyl methacrylate (PMMA)-coated hollow Sn-Co nanospheres (Sn-Co@PMMA) with superior electrochemical performance had been synthesized via a facile galvanic replacement method followed by an in situ emulsion polymerization route. The properties were investigated in detail and results show that the hollow Sn-Co nanospheres were evenly coated with PMMA. Benefiting from the protection of the PMMA layers, the hollow Sn-Co@PMMA nanocomposite is capable of retaining a high capacity of 590 mAh g-1 after 100 cycles with a coulomb efficiency above 98%, revealing better electrochemical properties compared with hollow Sn-Co anodes. The PMMA coating could help accommodate the mechanical strain caused by volume expansion and stabilize the solid electrolyte interphase (SEI) film formed on the electrode. Such a facile process could be further extended to other anode materials for lithium-ion batteries.

Preparation and properties of PMMA nanoparticles as 3 dimensional photonic crystals and its thin film via surfactant-free emulsion polymerization

NASA Astrophysics Data System (ADS)

Tahrin, Rabiatul Addawiyah Azwa; Azma, Nur Syafiqa; Kassim, Syara; Harun, Noor Aniza

2017-09-01

3-dimensional (3D) photonic crystals have been extended use in wide research and application from material to sensor. Nanoparticles of poly (methyl methacrylate) (PMMA) latex beads have been successfully prepared by green-chemistry approach where no surfactant, linking agent and solvent were involved. Regardless of the effect of initiator in polymerization reaction, this study presents the effect of temperature, monomer concentration, stirring speed and reaction period in order to tune the particle size. Its morphology of uniformity sized-tuned was confirming by using particle size analyzer (PSA) and scanning electron microscopy (SEM). The fabrication of 3D photonic crystals film by using self-assembly method to pattern the desired PMMA layers which is the most feasible, low cost method are also presented. The detailed properties of PMMA nanoparticles from this experimental study will be discussed and its potential used in photonic application will be explained.

Process for preparation of large-particle-size monodisperse latexes

NASA Technical Reports Server (NTRS)

Vanderhoff, J. W.; Micale, F. J.; El-Aasser, M. S.; Kornfeld, D. M. (Inventor)

1981-01-01

Monodisperse latexes having a particle size in the range of 2 to 40 microns are prepared by seeded emulsion polymerization in microgravity. A reaction mixture containing smaller monodisperse latex seed particles, predetermined amounts of monomer, emulsifier, initiator, inhibitor and water is placed in a microgravity environment, and polymerization is initiated by heating. The reaction is allowed to continue until the seed particles grow to a predetermined size, and the resulting enlarged particles are then recovered. A plurality of particle-growing steps can be used to reach larger sizes within the stated range, with enlarge particles from the previous steps being used as seed particles for the succeeding steps. Microgravity enables preparation of particles in the stated size range by avoiding gravity related problems of creaming and settling, and flocculation induced by mechanical shear that have precluded their preparation in a normal gravity environment.

Polyethylenimine-immobilized core-shell nanoparticles: synthesis, characterization, and biocompatibility test.

PubMed

Ratanajanchai, Montri; Soodvilai, Sunhapas; Pimpha, Nuttaporn; Sunintaboon, Panya

2014-01-01

Herein, we prepared PEI-immobilized core-shell particles possessing various types of polymer cores via a visible light-induced surfactant-free emulsion polymerization (SFEP) of three vinyl monomers: styrene (St), methyl methacrylate (MMA), and 2-hydroxyethyl methacrylate (HEMA). An effect of monomers on the polymerization and characteristics of resulting products was investigated. Monomers with high polarity can provide high monomer conversion, high percentage of grafted PEI, stable particles with uniform size distribution but less amino groups per particles. All prepared nanoparticles exhibited a core-shell nanostructure, containing PEI on the shell with hydrodynamic size around 140-230nm. For in-vitro study in Caco-2 cells, we found that the incorporation of PEI into these core-shell nanoparticles can significantly reduce its cytotoxic effect and also be able to internalized within the cells. Accordingly, these biocompatible particles would be useful for various biomedical applications, including gene transfection and intracellular drug delivery. © 2013.

3-Dimensional Colloidal Crystals From Hollow Spheres

NASA Astrophysics Data System (ADS)

Zhang, Jian; Work, William J.; Sanyal, Subrata; Lin, Keng-Hui; Yodh, A. G.

2000-03-01

We have succeeded in synthesizing submicron-sized, hollow PMMA spheres and self-assembling them into colloidal crystalline structures using the depletion force. The resulting structures can be used as templates to make high refractive-index contrast, porous, inorganic structures without the need to use calcination or chemical-etching. With the method of emulsion polymerization, we managed to coat a thin PMMA shell around a swellable P(MMA/MAA/EGDMA) core. After neutralization and heating above the glass transition temperature of PMMA, we obtained water-swollen hydrogel particles encapsulated in PMMA shells. These composite particles become hollow spheres after drying. We characterized the particles with both transmission electron microscopy (TEM) and dynamic light scattering (DLS). The TEM results confirmed that each sphere has a hollow core. The DLS results showed that our hollow spheres are submicron-sized, with a swelling ratio of at least 25%, and with a polydispersity less than 5%. We anticipate using this method in the near-future to encapsulate ferrofluid emulsion droplets and liquid crystal droplets.

A Facile Method for Preparation of Polymer Particles Having a "Cylindrical" Shape.

PubMed

Li, Wei; Suzuki, Toyoko; Minami, Hideto

2018-06-16

A facile and novel approach to prepare monodisperse polystyrene (PS) particles having a "cylindrical" shape was discovered. The proposed synthetic method involved dispersion polymerization of the spherical PS particles stirred in a polyvinylpyrrolidone (PVP) aqueous solution for several hours using a magnetic stirrer at room temperature. In the presence of PVP, the spherical PS particles deformed into cylindrical shapes following stirring; however, the particles did not deform in the absence of PVP. The deformation rate of the particles was affected by the molecular weight of the dissolved PVP. This stirring method is not only highly efficient and provides high yield, but is also applicable to other materials such as polymethyl methacrylate. Moreover, the cylindrical particles were successfully applied as particulate surfactants in a Pickering emulsion system, which exhibited excellent stability as comparison with the system using spherical particles as a surfactant. In the latter case, the emulsion was left standing for more than 4 months. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photo-triggered release in polyamide nanosized capsules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marturano, V.; Ambrogi, V.; Cerruti, P.

2014-05-15

In this work, nanosized capsules based on a lightly cross-linked polyamide containing azobenzene moieties in the main chain were synthesized by miniemulsion interfacial polymerization. The obtained nanocapsules were loaded either with toluene or with the fluorescent probe coumarin-6 as a core. Diameters of the nanocapsules were in the 100-900 nm range, depending on the selected emulsion conditions. The morphology and shape of the samples were observed by TEM and SEM while the emulsion droplets and nanocapsules size was measured by DLS. Under continuous UV irradiation the polymer underwent E-Z photoisomerization allowing the release of the encapsulated material. Variation in diametermore » of the nanocapsules with the time of UV irradiation was detected through DLS analysis. 10-30% growth was observed, depending on the sample. The kinetics of release of coumarin-6 was followed by spectrofluorimetry in ethanol. In absence of irradiation, the fluorescence intensity appeared to be constant over time, while it increased when the sample was irradiated with 360 nm UV light.« less

Retaining Oxidative Stability of Emulsified Foods by Novel Nonmigratory Polyphenol Coated Active Packaging.

PubMed

Roman, Maxine J; Decker, Eric A; Goddard, Julie M

2016-07-13

Oxidation causes lipid rancidity, discoloration, and nutrient degradation that decrease shelf life of packaged foods. Synthetic additives are effective oxidation inhibitors, but are undesirable to consumers who prefer "clean" label products. The aim of this study was to improve oxidative stability of emulsified foods by a novel nonmigratory polyphenol coated active packaging. Polyphenol coatings were applied to chitosan functionalized polypropylene (PP) by laccase assisted polymerization of catechol and catechin. Polyphenol coated PP exhibited both metal chelating (39.3 ± 2.5 nmol Fe(3+) cm(-2), pH 4.0) and radical scavenging (up to 52.9 ± 1.8 nmol Trolox eq cm(-2)) capacity, resulting in dual antioxidant functionality to inhibit lipid oxidation and lycopene degradation in emulsions. Nonmigratory polyphenol coated PP inhibited ferric iron promoted degradation better than soluble chelators, potentially by partitioning iron from the emulsion droplet interface. This work demonstrates that polyphenol coatings can be designed for advanced material chemistry solutions in active food packaging.

Synthesis and Evaluation of a Molecularly Imprinted Polymer for the Determination of Metronidazole in Water Samples.

PubMed

de León-Martínez, L Díaz; Rodríguez-Aguilar, M; Ocampo-Pérez, R; Gutiérrez-Hernández, J M; Díaz-Barriga, F; Batres-Esquivel, L; Flores-Ramírez, R

2018-03-01

A molecularly imprinted polymer was developed and evaluated for selective determination of metronidazole (MNZ) in wastewater. This was achieved by using sodium methacrylate as monomer, toluene as porogen, ethylene glycol dimethacrylate as crosslinker, azobisisobutyronitrile as initiator and metronidazole as template molecule to generate the selectivity of the polymer for the compound, as well as non-imprinted polymers were synthesized. Two different polymerization approaches were used, bulk and emulsion and the polymers obtained by emulsion presented higher retention percentages the MIP 2-M presented the higher retention (83%). The performed method, was validated in fortified water, showing linearity from 10 up to 1000 ng/mL; limit of detection and quantification for compound were between 3 and 10 ng/mL, respectively. Finally, the method was applied in samples of a wastewater treatment plant in the city of San Luis Potosí, México, and the concentrations of MNZ in these samples were 84.1-114 ng/mL.

In vitro evaluation of suspoemulsions for in situ-forming polymeric microspheres and controlled release of progesterone.

PubMed

Turino, Ludmila N; Mariano, Rodolfo N; Mengatto, Luciano N; Luna, Julio A

2015-01-01

One possibility to obtain a higher dose of drug in a lower formulation volume can be by using of saturated quantity of drug in one of the phases of an emulsion. These formulations are called suspoemulsions (S/O/W). When a hydrophobic polymer is added to the organic phase of suspoemulsions, these formulations can be used to entrap the drug inside microspheres after in situ precipitation of the polymer-drug-excipients mix. In this work, performance and stability of progesterone suspensions in triacetin as organic phase of suspoemulsions were evaluated. These formulations were compared with O/W emulsions. Mathematical models were used to study in vitro release profiles. The results confirmed that S/O/W systems could be an attractive alternative to O/W formulations for the entrapment of progesterone inside poly(d,l-lactide-co-glycolide) microspheres. Diffusive-based models fit the in vitro release of progesterone from in situ-formed microspheres. For longer release periods, a time-dependent diffusion coefficient was successfully estimated.

Microcapsule and methods of making and using microcapsules

DOEpatents

Okawa, David C.; Pastine, Stefan J.; Zettl, Alexander K.; Frechet, Jean M.J.

2014-09-02

An embodiment of a microcapsule includes a shell surrounding a space, a liquid within the shell, and a light absorbing material within the liquid. An embodiment of a method of making microcapsules includes forming a mixture of a light absorbing material and an organic solution. An emulsion of the mixture and an aqueous solution is then formed. A polymerization agent is added to the emulsion, which causes microcapsules to be formed. Each microcapsule includes a shell surrounding a space, a liquid within the shell, and light absorbing material within the liquid. An embodiment of a method of using microcapsules includes providing phototriggerable microcapsules within a bulk material. Each of the phototriggerable microcapsules includes a shell surrounding a space, a chemically reactive material within the shell, and a light absorbing material within the shell. At least some of the phototriggerable microcapsules are exposed to light, which causes the chemically reactive material to release from the shell and to come into contact with bulk material.

A New Adjuvant Combined with Inactivated Influenza Enhances Specific CD8 T Cell Response in Mice and Decreases Symptoms in Swine Upon Challenge.

PubMed

Bouguyon, Edwige; Goncalves, Elodie; Shevtsov, Alexander; Maisonnasse, Pauline; Remyga, Stepan; Goryushev, Oleg; Deville, Sebastien; Bertho, Nicolas; Ben Arous, Juliette

2015-11-01

Vaccination is the most effective way to control swine influenza virus (SIV) in the field. Classical vaccines are based on inactivated antigens formulated with an oil emulsion or a polymeric adjuvant. Standard adjuvants enhance the humoral response and orient the immune response toward a Th2 response. An important issue is that current vaccines do not protect against new strains. One approach to improve cross-protection is to enhance Th1 and cytotoxic responses. The development of adjuvants orienting the immune response of inactivated vaccines toward Th1/Cytotoxic responses would be highly beneficial. This study shows that the water in oil in water emulsion adjuvant Montanide™ ISA 201 VG allows the induction of anti-influenza CD8 T cell in mice and induces homologous protection against an H1N1 challenge in swine. Such adjuvants that induce both humoral and cell-mediated immunity could improve the protection conferred by SIV vaccines in the field.

Living supramolecular polymerization realized through a biomimetic approach

NASA Astrophysics Data System (ADS)

Ogi, Soichiro; Sugiyasu, Kazunori; Manna, Swarup; Samitsu, Sadaki; Takeuchi, Masayuki

2014-03-01

Various conventional reactions in polymer chemistry have been translated to the supramolecular domain, yet it has remained challenging to devise living supramolecular polymerization. To achieve this, self-organization occurring far from thermodynamic equilibrium—ubiquitously observed in nature—must take place. Prion infection is one example that can be observed in biological systems. Here, we present an ‘artificial infection’ process in which porphyrin-based monomers assemble into nanoparticles, and are then converted into nanofibres in the presence of an aliquot of the nanofibre, which acts as a ‘pathogen’. We have investigated the assembly phenomenon using isodesmic and cooperative models and found that it occurs through a delicate interplay of these two aggregation pathways. Using this understanding of the mechanism taking place, we have designed a living supramolecular polymerization of the porphyrin-based monomers. Despite the fact that the polymerization is non-covalent, the reaction kinetics are analogous to that of conventional chain growth polymerization, and the supramolecular polymers were synthesized with controlled length and narrow polydispersity.

Preparation and Characterization of Mesoporous Zirconia Made by Using a Poly (methyl methacrylate) Template

NASA Astrophysics Data System (ADS)

Duan, Guorong; Zhang, Chunxiang; Li, Aimei; Yang, Xujie; Lu, Lude; Wang, Xin

2008-03-01

Superfine powders of poly (methyl methacrylate) (PMMA) have been prepared by means of an emulsion polymerization method. These have been used as templates in the synthesis of tetragonal phase mesoporous zirconia by the sol gel method, using zirconium oxychloride and oxalic acid as raw materials. The products have been characterized by infrared spectroscopy, X-ray diffraction analysis, transmission electron microscopy, N2 adsorption-desorption isotherms, and pore size distribution. The results indicate that the average pore size was found to be 3.7 nm.

Synthesis of Size-Tunable CO2-Philic Imprinted Polymeric Particles (MIPs) for Low-Pressure CO2 Capture Using Oil-in-Oil Suspension Polymerization.

PubMed

Nabavi, Seyed Ali; Vladisavljević, Goran T; Zhu, Yidi; Manović, Vasilije

2017-10-03

Highly selective molecularly imprinted poly[acrylamide-co-(ethylene glycol dimethacrylate)] polymer particles (MIPs) for CO 2 capture were synthesized by suspension polymerization via oil-in-oil emulsion. Creation of CO 2 -philic, amide-decorated cavities in the polymer matrix led to a high affinity to CO 2 . At 0.15 bar CO 2 partial pressure, the CO 2 /N 2 selectivity was 49 (corresponding to 91% purity of the gas stream after regeneration), and reached 97 at ultralow CO 2 partial pressures. The imprinted polymers showed considerably higher CO 2 uptakes compared to their nonimprinted counterparts, and the maximum equilibrium CO 2 capture capacity of 1.1 mmol g -1 was achieved at 273 K. The heat of adsorption was below 32 kJ mol -1 and the temperature of onset of intense thermal degradation was 351-376 °C. An increase in monomer-to-cross-linker molar ratio in the dispersed phase up to 1:2.5 led to a higher affinity toward CO 2 due to higher density of selective amide groups in the polymer network. MIPs are a promising option for industrial packed and fluidized bed CO 2 capture systems due to large particles with a diameter up to 1200 μm and irregular oblong shapes formed due to arrested coalescence during polymerization, occurring as a result of internal elasticity of the partially polymerized semisolid drops.

Extraction of anionic dye from aqueous solutions by emulsion liquid membrane.

PubMed

Dâas, Attef; Hamdaoui, Oualid

2010-06-15

In this work, the extraction of Congo red (CR), an anionic disazo direct dye, from aqueous solutions by emulsion liquid membrane (ELM) was investigated. The important operational parameters governing emulsion stability and extraction behavior of dye were studied. The extraction of CR was influenced by a number of variables such as surfactant concentration, stirring speed, acid concentration in the feed solution and volume ratios of internal phase to organic phase and of emulsion to feed solution. Under most favorable conditions, practically all the CR molecules present in the feed phase were extracted even in the presence of salt (NaCl). At the optimum experimental conditions, total removal of antharaquinonic dye Acid Blue 25 was attained after only 10 min. Influence of sodium carbonate concentration as internal receiving phase on the stripping efficiency of CR was examined. The best sodium carbonate concentration in the internal phase that conducted to excellent stripping efficiency (>99%) and emulsion stability was 0.1N. The membrane recovery was total and the permeation of CR was not decreased up to seven runs. ELM process is a promising alternative to conventional methods and should increase awareness of the potential for recovery of anionic dyes. Copyright 2010 Elsevier B.V. All rights reserved.

The pharmacopeial evolution of intralipid injectable emulsion in plastic containers: from a coarse to a fine dispersion.

PubMed

Driscoll, David F

2009-02-23

On December 1, 2007, the United States Pharmacopeia (USP) adopted Chapter 729 entitled Globule Size Distribution in Lipid Injectable Emulsions that contains two globule sizing methods and criteria to measure the mean droplet diameter (MDD) and the large-diameter tail of the globule size distribution to meet pharmacopeial specifications. The first of these measures, as the intensity-weighted MDD expressed in nanometers, must be less than 500 nm. The second measure, as the volume-weighted percentage of fat greater than 5 microm or PFAT(5), must be less than 0.05%. These limits were first suggested in 2001 based on an analysis of 16 lipid injectable emulsions available worldwide. In 2004, the packaging of the innovator lipid emulsion product Intralipid was changed from conventional glass bottles to plastic containers in the U.S. A subsequent analysis of the emulsion in its new container showed it to be more coarse than its previous glass counterpart and now failed the PFAT(5) limit. In 2007, it was announced that Intralipid in plastic containers was reformulated to meet the pharmacopeial limits. To track the time course of its transition from a coarse to a fine dispersion, 31 lots of Intralipid with expiration dates spanning five years were investigated.

Comparison of retention between maxillary milled and conventional denture bases: A clinical study.

PubMed

AlHelal, Abdulaziz; AlRumaih, Hamad S; Kattadiyil, Mathew T; Baba, Nadim Z; Goodacre, Charles J

2017-02-01

Clinical studies comparing the retention values of milled denture bases with those of conventionally processed denture bases are lacking. The purpose of this clinical study was to compare the retention values of conventional heat-polymerized denture bases with those of digitally milled maxillary denture bases. Twenty individuals with completely edentulous maxillary arches participated in this study. Definitive polyvinyl siloxane impressions were scanned (iSeries; Dental Wings), and the standard tessellation language files were sent to Global Dental Science for the fabrication of a computer-aided design and computer-aided manufacturing (CAD-CAM) milled denture base (group MB) (AvaDent). The impression was then poured to obtain a definitive cast that was used to fabricate a heat-polymerized acrylic resin denture base resin (group HB). A custom-designed testing device was used to measure denture retention (N). Each denture base was subjected to a vertical pulling force by using an advanced digital force gauge 3 times at 10-minute intervals. The average retention of the 2 fabrication methods was compared using repeated ANOVA (α=.05). Significantly increased retention was observed for the milled denture bases compared with that of the conventional heat-polymerized denture bases (P<.001). The retention offered by milled complete denture bases from prepolymerized poly(methyl methacrylate) resin was significantly higher than that offered by conventional heat- polymerized denture bases. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Value-based medicine, comparative effectiveness, and cost-effectiveness analysis of topical cyclosporine for the treatment of dry eye syndrome.

PubMed

Brown, Melissa M; Brown, Gary C; Brown, Heidi C; Peet, Jonathan; Roth, Zachary

2009-02-01

To assess the comparative effectiveness and cost-effectiveness (cost-utility) of a 0.05% emulsion of topical cyclosporine (Restasis; Allergan Inc, Irvine, California) for the treatment of moderate to severe dry eye syndrome that is unresponsive to conventional therapy. Data from 2 multicenter, randomized, clinical trials and Food and Drug Administration files for topical cyclosporine, 0.05%, emulsion were used in Center for Value-Based Medicine analyses. Analyses included value-based medicine as a comparative effectiveness analysis and average cost-utility analysis using societal and third-party insurer cost perspectives. Outcome measures of comparative effectiveness were quality-adjusted life-year (QALY) gain and percentage of improvement in quality of life, and for cost-effectiveness were cost-utility ratio (CUR) using dollars per QALY. Topical cyclosporine, 0.05%, confers a value gain (comparative effectiveness) of 0.0319 QALY per year compared with topical lubricant therapy, a 4.3% improvement in quality of life for the average patient with moderate to severe dry eye syndrome that is unresponsive to conventional lubricant therapy. The societal perspective incremental CUR for cyclosporine over vehicle therapy is $34,953 per QALY and the societal perspective average CUR is $11,199 per QALY. The third-party-insurer incremental CUR is $37,179 per QALY, while the third-party-insurer perspective average CUR is $34,343 per QALY. Topical cyclosporine emulsion, 0.05%, confers considerable patient value and is a cost-effective therapy for moderate to severe dry eye syndrome that is unresponsive to conventional therapy.

Investigation of non-isocyanate urethane functional latexes and carbon nanofiller/epoxy coatings

NASA Astrophysics Data System (ADS)

Meng, Lei

This dissertation consists of two parts. In the first part, a new class of non-isocyanate urethane methacrylates was synthesized and the effect of the new monomers on the urethane functional latex was investigated. The second part focused on a comparison of carbon nanofillers in inorganic/organic epoxy coating system for anticorrosive applications. A new class of non-isocyanate urethane methacrylates (UMAs) monomers was synthesized through an environmentally friendly non-isocyanate pathway. The kinetics of seeded semibatch emulsion polymerization of UMAs with methyl methacrylate (MMA) and butyl acrylate (BA) was monitored. The particle size and morphology were investigated by dynamic light scattering (DLS), ultrasound acoustic attenuation spectroscopy (UAAS) and transmission electron microscopy (TEM). The minimum film formation temperature (MFFT), mechanical and viscoelastic properties were studied. It was found that the emulsion polymerization processes all proceeded via Smith-Ewart control, leading to the uniform morphology and particle size. The glass transition temperature (Tg) and the mechanical properties of poly(MMA/BA/UMA) decreased with the increasing chain length of urethane methacrylate monomers due to the increasing flexibility of side chains. Without the effect of Tg, lower MFFT and improved mechanical properties were observed from urethane functional latexes. The improved mechanical properties were due to the increasing particle interaction by forming hydrogen bonding. Furthermore, the effect of urethane functionality in terms of the polymer composition, the location and the concentration was investigated by the batch, single-stage and two-stage semibatch polymerization of 2-[(butylcarbamoyl)oxy]ethyl methacrylate (BEM) with MMA and BA. The core-shell and homogeneous structures were evaluated by TEM, differential scanning calorimetry (DSC), and solid state nuclear magnetic resonance (SS-NMR). The compositional drift was observed from the batch polymerization. The mechanical properties were improved with increasing urethane and the best was from the urethane in the shell due to higher concentration of urethane in the continuous phase. The inorganic/organic alkoxysilane modified epoxy coating system was formulated with carbon nanofillers, i.e. carbon black, mixture of carbon black and nanotubes, unpurified and purified non-fullerene carbon nanotubes and fullerene carbon nanotubes. Mechanical, thermal, electrical and anticorrosive properties of cured films were evaluated by tensile tests, DMTA, DSC, four-point probe method and electrochemical impedance spectroscopy (EIS), respectively. It was found that the most efficient material to enhance the electrical conductivity and anticorrosive properties of nanocomposite coating systems was fullerene CNTs.

A new nanocomposite forward osmosis membrane custom-designed for treating shale gas wastewater

PubMed Central

Qin, Detao; Liu, Zhaoyang; Delai Sun, Darren; Song, Xiaoxiao; Bai, Hongwei

2015-01-01

Managing the wastewater discharged from oil and shale gas fields is a big challenge, because this kind of wastewater is normally polluted by high contents of both oils and salts. Conventional pressure-driven membranes experience little success for treating this wastewater because of either severe membrane fouling or incapability of desalination. In this study, we designed a new nanocomposite forward osmosis (FO) membrane for accomplishing simultaneous oil/water separation and desalination. This nanocomposite FO membrane is composed of an oil-repelling and salt-rejecting hydrogel selective layer on top of a graphene oxide (GO) nanosheets infused polymeric support layer. The hydrogel selective layer demonstrates strong underwater oleophobicity that leads to superior anti-fouling capability under various oil/water emulsions, and the infused GO in support layer can significantly mitigate internal concentration polarization (ICP) through reducing FO membrane structural parameter by as much as 20%. Compared with commercial FO membrane, this new FO membrane demonstrates more than three times higher water flux, higher removals for oil and salts (>99.9% for oil and >99.7% for multivalent ions) and significantly lower fouling tendency when investigated with simulated shale gas wastewater. These combined merits will endorse this new FO membrane with wide applications in treating highly saline and oily wastewaters. PMID:26416014

Polyacrylamide medium for the electrophoretic separation of biomolecules

DOEpatents

Madabhushi, Ramakrishna S.; Gammon, Stuart A.

2003-11-11

A polyacryalmide medium for the electrophoretic separation of biomolecules. The polyacryalmide medium comprises high molecular weight polyacrylamides (PAAm) having a viscosity average molecular weight (M.sub.v) of about 675-725 kDa were synthesized by conventional red-ox polymerization technique. Using this separation medium, capillary electrophoresis of BigDye DNA sequencing standard was performed. A single base resolution of .about.725 bases was achieved in .about.60 minute in a non-covalently coated capillary of 50 .mu.m i.d., 40 cm effective length, and a filed of 160 V/cm at 40.degree. C. The resolution achieved with this formulation to separate DNA under identical conditions is much superior (725 bases vs. 625 bases) and faster (60 min. vs. 75 min.) to the commercially available PAAm, such as supplied by Amersham. The formulation method employed here to synthesize PAAm is straight-forward, simple and does not require cumbersome methods such as emulsion polymerizaiton in order to achieve very high molecular weights. Also, the formulation here does not require separation of PAAm from the reaction mixture prior to reconstituting the polymer to a final concentration. Furthermore, the formulation here is prepared from a single average mol. wt. PAAm as opposed to the mixture of two different average mo. wt. PAAm previously required to achieve high resolution.

Facile fabrication of bowl-shaped microparticles for oral curcumin delivery to ulcerative colitis tissue.

PubMed

Chen, Qiubing; Gou, Shuangquan; Huang, Yamei; Zhou, Xin; Li, Qian; Han, Moon Kwon; Kang, Yuejun; Xiao, Bo

2018-05-05

Oral microparticles (MPs) have been considered as promising drug carriers in the treatment of ulcerative colitis (UC). Here, a facile strategy based on a conventional emulsion-solvent evaporation technique was used to fabricate bowl-shaped MPs (BMPs), and these MPs loaded with anti-inflammatory drug (curcumin, CUR) during the fabrication process. The physicochemical properties of the resultant BMPs were characterized by dynamic light scattering, scanning electron microscope, confocal laser scanning microscope and X-ray diffraction as well as contact angle goniometer. Results indicated that BMPs had a desirable hydrodynamic diameter (1.84 ± 0.20 μm), a negative zeta potential (-26.5 ± 1.13 mV), smooth surface morphology, high CUR encapsulation efficiency and controlled drug release profile. It was found that CUR molecules were dispersed in an amorphous state within the polymeric matrixes. In addition, BMPs showed excellent hydrophilicity due to the presence of Pluronic F127 and poly(vinyl alcohol) on their surface. More importantly, orally administered BMPs could efficiently alleviate UC based on a dextran sulfate sodium-induced mouse model. These results collectively suggest that BMP can be exploited as a readily scalable oral drug delivery system for UC therapy. Copyright © 2018 Elsevier B.V. All rights reserved.

Altering the level of calcium changes the physical properties and digestibility of casein-based emulsion gels.

PubMed

McIntyre, Irene; O Sullivan, Michael; O Riordan, Dolores

2017-04-19

Casein-based emulsion gels prepared with different types of lipid (i.e. milk fat or rapeseed oil) were formulated with high (774 mg Ca per 100 g) or low (357 mg Ca per 100 g) calcium levels by blending acid and rennet casein. Their physicochemical characteristics (i.e. composition, texture, microstructure & water mobility) and in vitro digestibility were compared to conventionally formulated high-calcium (723 mg Ca per 100 g) emulsion gels made from rennet casein with calcium chelating salts (CCS). CCS-free, high-calcium emulsion gels were significantly (p ≤ 0.05) softer than those with low calcium levels (possibly due to their shorter manufacture time and higher pH) and showed the highest rates of disintegration during simulated gastric digestion. Despite having a higher moisture to protein ratio, the high-calcium emulsion gels containing CCS had broadly similar hardness values to those of high-calcium concentration prepared without CCS, but had higher cohesiveness. The high-calcium matrices containing CCS had quite a different microstructure and increased water mobility compared to those made without CCS and showed the slowest rate (p ≤ 0.05) of disintegration in the gastric environment. Gastric resistance was not affected by the type of lipid phase. Conversely, fatty acid release was similar for all emulsion gels prepared from milk fat, however, high-calcium emulsion gels (CCS-free) prepared from rapeseed oil showed higher lipolysis. Results suggest that food matrix physical properties can be modified to alter resistance to gastric degradation which may have consequences for the kinetics of nutrient release and delivery of bioactives sensitive to the gastric environment.

Stabilization of food dispersions by enzymes.

PubMed

Zeeb, Benjamin; Fischer, Lutz; Weiss, Jochen

2014-02-01

Food dispersions have become essential vehicles to carry and deliver functional ingredients such as bioactive compounds, flavors, antimicrobials, antioxidants, colors and vitamins. Most of these systems are thermodynamically unstable tending to break down over time. Much research has therefore been carried out to develop methodologies to improve their long-term stability. In this review, we will introduce readers to a new approach that has been developed over the past years to stabilize food dispersions, i.e. by use of various enzymes. First, basic design principles of modern food dispersions including conventional emulsions, multiple emulsions, multilayered emulsions, solid lipid particle suspensions, and liposomes are discussed. Enzymes able to generate intra- and intermolecular crosslinks between proteins and/or polysaccharides will be reviewed and specific reactions catalyzed by, e.g., transglutaminase, laccase, tyrosinase, sulfhydryl oxidase, glucose oxidase, lipoxygenase, polyphenol oxidase, peroxidase, and lysyl oxidase will be highlighted. Finally, potential applications of this enzymatic approach in the food industry will be critically discussed.

Thermodynamic signature of secondary nano-emulsion formation by isothermal titration calorimetry.

PubMed

Fotticchia, Iolanda; Fotticchia, Teresa; Mattia, Carlo Andrea; Netti, Paolo Antonio; Vecchione, Raffaele; Giancola, Concetta

2014-12-09

The stabilization of oil in water nano-emulsions by means of a polymer coating is extremely important; it prolongs the shelf life of the product and makes it suitable for a variety of applications ranging from nutraceutics to cosmetics and pharmaceutics. To date, an effective methodology to assess the best formulations in terms of thermodynamic stability has yet to be designed. Here, we perform a complete physicochemical characterization based on isothermal titration calorimetry (ITC) compared to conventional dynamic light scattering (DLS) to identify polymer concentration domains that are thermodynamically stable and to define the degree of stability through thermodynamic functions depending upon any relevant parameter affecting the stability itself, such as type of polymer coating, droplet distance, etc. For instance, the method was proven by measuring the energetics in the case of two different biopolymers, chitosan and poly-L-lysine, and for different concentrations of the emulsion coated with poly-L-lysine.

Under-oil superhydrophilic wetted PVDF electrospun modified membrane for continuous gravitational oil/water separation with outstanding flux.

PubMed

Obaid, M; Mohamed, Hend Omar; Yasin, Ahmed S; Yassin, Mohamed A; Fadali, Olfat A; Kim, HakYong; Barakat, Nasser A M

2017-10-15

Water in the world is becoming an increasingly scarce commodity and the membrane technology is a most effective strategy to address this issue. However, the fouling and low flux of the polymeric membrane remains the big challenges. Novel modified Polyvinylidene fluoride (PVDF) membrane was introduced, in this work, using a novel treatment technique for an electrospun polymeric PVDF membrane to be used in oil/water separation systems. The Characterizations of the modified and pristine membranes showed distinct changes in the phase and crystal structure of the membrane material as well as the wettability. The modification process altered the surface morphology and structure of the membrane by forming hydrophilic microspheres on the membrane surface. Therefore, the proposed treatment converts the membrane from highly hydrophobic to be a superhydrophilic under-oil when wetted with water. Accordingly, in the separation of oil/water mixtures, the modified membrane can achieve an outstanding flux of 20664 L/m 2 . hr under gravity, which is higher than the pristine membrane by infinite times. Moreover, in the separation of the emulsion, a high flux of 2727 L/m 2 . h was achieved. The results exhibited that the modified membrane can treat a huge amount of oily water with a minimal energy consumption. The corresponding separation efficiencies of both of oil/water mixtures and emulsion are more than 99%. The achieved characteristics for the modified and pristine membranes could be exploited to design a novel continuous system for oil/water separation with an excellent efficiency. Copyright © 2017 Elsevier Ltd. All rights reserved.

Emulsion Solvent Evaporation-Induced Self-Assembly of Block Copolymers Containing pH-Sensitive Block.

PubMed

Wu, Yuqing; Wang, Ke; Tan, Haiying; Xu, Jiangping; Zhu, Jintao

2017-09-26

A simple yet efficient method is developed to manipulate the self-assembly of pH-sensitive block copolymers (BCPs) confined in emulsion droplets. Addition of acid induces significant variation in morphological transition (e.g., structure and surface composition changes) of the polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) assemblies, due to the hydrophobic-hydrophilic transition of the pH-sensitive P4VP block via protonation. In the case of pH > pKa (P4VP) (pKa (P4VP) = 4.8), the BCPs can self-assemble into pupa-like particles because of the nearly neutral wetting of PS and P4VP blocks at the oil/water interface. As expected, onion-like particles obtained when pH is slightly lower than pKa (P4VP) (e.g., pH = 3.00), due to the interfacial affinity to the weakly hydrophilic P4VP block. Interestingly, when pH was further decreased to ∼2.5, interfacial instability of the emulsion droplets was observed, and each emulsion droplet generated nanoscale assemblies including vesicles, worm-like and/or spherical micelles rather than a nanostructured microparticle. Furthermore, homopolymer with different molecular weights and addition ratio are employed to adjust the interactions among copolymer blocks. By this means, particles with hierarchical structures can be obtained. Moreover, owing to the kinetically controlled processing, we found that temperature and stirring speed, which can significantly affect the kinetics of the evaporation of organic solvent and the formation of particles, played a key role in the morphology of the assemblies. We believe that manipulation of the property for the aqueous phase is a promising strategy to rationally design and fabricate polymeric assemblies with desirable shapes and internal structures.

Essential Fatty Acid Deficiency in 2015: The Impact of Novel Intravenous Lipid Emulsions.

PubMed

Gramlich, Leah; Meddings, Liisa; Alberda, Cathy; Wichansawakun, Sanit; Robbins, Sarah; Driscoll, David; Bistrian, Bruce

2015-09-01

The fatty acids, linoleic acid (18:2ω-6) and α-linolenic acid (18:3ω-3), are essential to the human diet. When these essential fatty acids are not provided in sufficient quantities, essential fatty acid deficiency (EFAD) develops. This can be suggested clinically by abnormal liver function tests or biochemically by an elevated Mead acid and reduced linoleic acid and arachidonic acid level, which is manifested as an elevated triene/tetraene ratio of Mead acid/arachidonic acid. Clinical features of EFAD may present later. With the introduction of novel intravenous (IV) lipid emulsions in North America, the proportion of fatty acids provided, particularly the essential fatty acids, varies substantially. We describe a case series of 3 complicated obese patients who were administered parenteral nutrition (PN), primarily using ClinOleic 20%, an olive oil-based lipid emulsion with reduced amounts of the essential fatty acids, linoleic and α-linolenic, compared with more conventional soybean oil emulsions throughout their hospital admission. Essential fatty acid profiles were obtained for each of these patients to investigate EFAD as a potential cause of abnormal liver enzymes. Although the profiles revealed reduced linoleic acid and elevated Mead acid levels, this was not indicative of the development of essential fatty acid deficiency, as reflected in the more definitive measure of triene/tetraene ratio. Instead, although the serum fatty acid panel reflected the markedly lower but still adequate dietary linoleic acid content and greatly increased oleic acid content in the parenteral lipid emulsion, the triene/tetraene ratio remained well below the level, indicating EFAD in each of these patients. The availability and use of new IV lipid emulsions in PN should encourage the clinician to review lipid metabolism based on the quantity of fatty acids provided in specific parenteral lipid emulsions and the expected impact of these lipid emulsions (with quite different fatty acid composition) on measured fatty acid profiles. © 2015 American Society for Parenteral and Enteral Nutrition.

Biodegradable metal adsorbent synthesized by graft polymerization onto nonwoven cotton fabric

NASA Astrophysics Data System (ADS)

Sekine, Ayako; Seko, Noriaki; Tamada, Masao; Suzuki, Yoshio

2010-01-01

A fibrous adsorbent for Hg ions was synthesized by radiation-induced emulsion graft polymerization of glycidyl methacrylate (GMA) onto a nonwoven cotton fabric and subsequent chemical modification. The optimal pre-irradiation dose for initiation of the graft polymerization of GMA, which minimized the effects of radiation damage on the mechanical strength of the nonwoven cotton fabric, was found to be 10 kGy. The GMA-grafted nonwoven cotton fabric was subsequently modified with ethylenediamine (EDA) or diethylenetriamine (DETA) to obtain a Hg adsorbent. The resulting amine-type adsorbents were evaluated for batch and continuous adsorption of Hg. In batch adsorption, the distribution coefficients of Hg reached 1.9×10 5 and 1.0×10 5 for EDA- and DETA-type adsorbents, respectively. A column packed with EDA-type adsorbent removed Hg from 1.8 ppm Hg solution at a space velocity of 100 h -1, which corresponds to 16,000 times the volume of the packed adsorbent. The adsorbed Hg on the EDA-type adsorbent could be completely eluted by 1 M HCl solution. A microbial oxidative degradation test revealed that the EDA-type adsorbent is biodegradable.

A solid colloidal drug delivery system for the eye: encapsulation of pilocarpin in nanoparticles.

PubMed

Harmia, T; Speiser, P; Kreuter, J

1986-01-01

The present study was undertaken in order to encapsulate pilocarpin into nanoparticles. Two principally different methods for manufacturing these particles were investigated. Firstly, pilocarpin was dissolved in an aqueous medium in which the polymerization was carried out, and secondly, the polymerizing monomer was kept saturated with the drug solution under acidic conditions resulting in an incorporation into the nanoparticles in an aqueous environment. The amount of pilocarpin that could be incorporated into the nanoparticles was found to be largely influenced by the temperature at which the nanoparticles were produced and by the stabilizers used. At low temperatures, up to 60 per cent of pilocarpin nitrate could be encapsulated into butylcyanoacrylate nanoparticles using emulsion polymerization techniques. Larger amounts of pilocarpin could not be incorporated because of the hydrophilicity of the salts of this drug. The physico-chemical characteristics of the nanoparticles are reported: the particle size and morphology were determined by scanning and transmission electron microscopy and photon correlation spectrometry. The average particle size was about 100 nm. The results obtained in this study show that photon correlation spectrometry is a suitable method for the sizing of nanoparticles.

Erosion prevention during highway construction by the use of sprayed on chemicals.

DOT National Transportation Integrated Search

1972-01-01

The purpose of this study was to evaluate the erosion inhibiting potential of nine commercial spray on plastic chemicals. All chemicals were also compared with the conventional method of straw tacked with an asphalt emulsion, and with untreated soil....

Comparative evaluation of surface porosities in conventional heat polymerized acrylic resin cured by water bath and microwave energy with microwavable acrylic resin cured by microwave energy

PubMed Central

Singh, Sunint; Palaskar, Jayant N.; Mittal, Sanjeev

2013-01-01

Background: Conventional heat cure poly methyl methacrylate (PMMA) is the most commonly used denture base resin despite having some short comings. Lengthy polymerization time being one of them and in order to overcome this fact microwave curing method was recommended. Unavailability of specially designed microwavable acrylic resin made it unpopular. Therefore, in this study, conventional heat cure PMMA was polymerized by microwave energy. Aim and Objectives: This study was designed to evaluate the surface porosities in PMMA cured by conventional water bath and microwave energy and compare it with microwavable acrylic resin cured by microwave energy. Materials and Methods: Wax samples were obtained by pouring molten wax into a metal mold of 25 mm × 12 mm × 3 mm dimensions. These samples were divided into three groups namely C, CM, and M. Group C denotes conventional heat cure PMMA cured by water bath method, CM denotes conventional heat cure PMMA cured by microwave energy, M denotes specially designed microwavable acrylic denture base resin cured by microwave energy. After polymerization, each sample was scanned in three pre-marked areas for surface porosities using the optical microscope. As per the literature available, this instrument is being used for the first time to measure the porosity in acrylic resin. It is a reliable method of measuring area of surface pores. Portion of the sample being scanned is displayed on the computer and with the help of software area of each pore was measured and data were analyzed. Results: Conventional heat cure PMMA samples cured by microwave energy showed maximum porosities than the samples cured by conventional water bath method and microwavable acrylic resin cured by microwave energy. Higher percentage of porosities was statistically significant, but well within the range to be clinically acceptable. Conclusion: Within the limitations of this in-vitro study, conventional heat cure PMMA can be cured by microwave energy without compromising on its property such as surface porosity. PMID:24015000

An injectable hybrid nanoparticle-in-oil-in-water submicron emulsion for improved delivery of poorly soluble drugs

NASA Astrophysics Data System (ADS)

Wang, Shuo; Wang, Hua; Liang, Wenquan; Huang, Yongzhuo

2012-04-01

Poor drugability problems are commonly seen in a class of chemical entities with poor solubility in water and oil, and moreover, physicochemical instability of these compounds poses extra challenges in design of dosage forms. Such problems contribute a significant high failure rate in new drug development. A hybrid nanoparicle-in-oil-in-water (N/O/W) submicron emulsion was proposed for improved delivery of poorly soluble and unstable drugs (e.g., dihydroartemisinin (DHA)). DHA is known for its potent antimalarial effect and antitumor activity. However, its insolubility and instability impose big challenges for formulations, and so far, no injectable dosage forms are clinically available yet. Therefore, an injectable DHA N/O/W system was developed. Unlike other widely-explored systems (e.g., liposomes, micelles, and emulsions), in which low drug load and only short-term storage are often found, the hybrid submicron emulsion possesses three-fold higher drug-loading capacity than the conventional O/W emulsion. Of note, it can be manufactured into a freeze-drying form and can render its storage up to 6 months even in room temperature. The in vivo studies demonstrated that the PK profiles were significantly improved, and this injectable system was effective in suppressing tumor growth. The strategy provides a useful solution to effective delivery of such a class of drugs.

Bacterial adhesion on conventional and self-ligating metallic brackets after surface treatment with plasma-polymerized hexamethyldisiloxane.

PubMed

Tupinambá, Rogerio Amaral; Claro, Cristiane Aparecida de Assis; Pereira, Cristiane Aparecida; Nobrega, Celestino José Prudente; Claro, Ana Paula Rosifini Alves

2017-01-01

Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. Hexamethyldisiloxane (HMDSO) polymer films were deposited on conventional (n = 10) and self-ligating (n = 10) stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD) radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM) analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region) and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI) and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. Significant statistical differences (p< 0.05) for surface roughness and bacterial adhesion reduction were observed on conventional brackets after surface treatment and between conventional and self-ligating brackets; no significant statistical differences were observed between self-ligating groups (p> 0.05). Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film.

Industrywide studies report of an in-depth survey at Copolymer Rubber and Chemical Corporation, Baton Rouge, Louisiana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krishnan, E.R.; Fajen, J.M.

1987-05-08

An in depth industrial hygiene survey was conducted at the Copolymer Rubber and Chemical Corporation located in Baton Rouge, Louisiana. The facility produced styrene-butadiene rubber and nitrile-butadiene rubber by continuous emulsion polymerization. The ultimate use of this product was for the manufacture of tire and rubber products. The authors recommend that leaking pumps which can present a potential for 1,3-butadiene exposure in the tank farm and recovery areas should be controlled through the use of dual mechanical seals. Employees assigned to maintenance tasks should use respirators with organic vapor cartridges.

Colloidal crystal beads composed of core-shell particles for multiplex bioassay.

PubMed

Xu, Hua; Zhu, Cun; Zhao, Yuanjin; Zhao, Xiangwei; Hu, Jing; Gu, Zhongze

2009-04-01

A convenient method was developed to fabricate colloidal crystal beads (CCBs) with tough mechanical strength, which was used as encoded carriers for multiplex bioassay. The latex particles used for the construction of the CCBs were designed with a rigid core PS and a elastomeric shell poly(MMA/EA/MAA), and were prepared via one-step soap-free emulsion polymerization. The as-above-prepared CCBs were thermo-treated to drive the elastomeric shells of adjacent latex particles joining together. It was found that the coalescence of latex particles can greatly improve the mechanical strength of the CCBs for multiplex bioassay.

Exploring the Dynamics and Structure of Soft Colloids at Oil-water Interfaces

NASA Astrophysics Data System (ADS)

Kwok, Man Hin

The ability of solid colloidal particles to physically stabilize emulsions, also referred to as Pickering emulsions, has been studied for a long time since their activity at the interface was discovered one hundred years ago. Pickering emulsions display various interesting phenomena because of it high desorption energy at the interface compared with conventional surfactant stabilizers. In addition, Pickering emulsions are considered to be 'surfactant free' emulsion and the adverse effects of using surfactants could be eliminated. In the past few years, the use of submicrometer, poly(N-isopropylacrylamide) (PNIPAM)-based mcirogel particles for stabilizing emulsions has captured the interest of many scientists. Being soft, the microgels, which are spherical in solution, become deformed at the oil-water interface. This deformability leads to the special dynamic properties of interfacial layers and packing structures, which in turn alters the interfacial tension and the rheological properties of the interface. In addition, being responsiveness, PNIPAM microgels enable emulsions to be prepared and broken on demand. Despite all of the practical advantages and unique properties that have already been demonstrated, the mechanisms that govern emulsion stabilization and destabilization using microgels are far from completely understood. The study of soft colloids at the interface thus is of great academic interest and the fundamental understanding of them is the key to achieve the application potential of such novel materials. This thesis focuses on the dynamics and structure of soft colloidal particles at the oil-water interfaces. First, in order to prepare tailored colloids for the study, the syntheses of multi-responsive PNIPAM microgels with different size, co-monomers, deformability and morphologies were thoroughly investigated. The combination of semi-batch synthesis and temperature-programmed technique resulted in a novel preparation of micron-sized PNIPAM microgels. Various experimental parameters were tested and modified in order to give microgels with optimized quality. The thermo- and pH- responsiveness of these microgels were characterized by laser diffraction and dynamic light scattering (DLS). Next, a novel labeling technique of the soft PNIPAM microgel particles was developed. This technique was based on the physical adsorption of small fluorescent molecules. Instead of chemically bonded dye molecules, these adsorbed fluorescent dyes could move freely inside the polymer network of the microgel particle. It was also found that the fluorescent dye interacted with different parts of the microgel differently. Therefore, the internal structure and morphology of microgels could be directly visualized by confocal laser scanning microscopy (CLSM) in aqueous environment. The improvement of imaging techniques of microgel particles is essential for studying their behavior at the oil-water interface. It is because conventional scanning electron microscopy (SEM) requires dried sample, which might not reflects the actual states of microgels in aqueous environment. With the improved labeling method under CLSM mentioned above, the conformation of micron-sized PNIPAM microgel particles was captured at the oil-water interface. Particularly, anisotropic deformation of soft pH-responsive microgels was observed at the oil-water interface. Nevertheless, it was found that microgels were not likely to deform significantly unless they were extremely swollen. We also use Langmuir trough to study the dynamics of microgel at an interface with changing area. Forced desorption-spontaneous adsorption cycles of microgel particles at the oil-water interface were successfully demonstrated. More interestingly, it was discovered that the microgel particles would be desorbed before having a significant deformation in Langmuir trough compression. Finally, the emulsion stability of the microgel stabilized Pickering emulsion was characterized by centrifugation. By comparing the stability of different microgels in different conditions, the correlation between the microgel properties and the corresponding Pickering emulsion stability was found. The emulsion stability and the interfacial behaviors of PNIPAM based microgels can now be better controlled and predicted, which gives great advantages for future applications using soft colloids as stabilizers.

WE-AB-BRA-03: Non-Invasive Controlled Release from Implantable Hydrogel Scaffolds Using Ultrasound

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moncion, A; Kripfgans, O.D; Putnam, A.J

Purpose: To control release of a model payload in acoustically responsive scaffolds (ARSs) using focused ultrasound (FUS). Methods: Fluorescently-labeled dextran (10 kDa) was encapsulated in sonosensitive perfluorocarbon (C{sub 6}F{sub 14} or C{sub 5}F{sub 12}) double emulsions (mean diameter: 2.9±0.1 µm). For in vitro release studies, 0.5 mL ARSs (10 mg/mL fibrin, 1% (v/v) emulsion) were polymerized in 24 well plates and covered with 0.5 mL medium. Starting one day after polymerization, ARSs were exposed to FUS (2.5 MHz, Pr = 8 MPa, 13 cycles, 100 Hz PRF) for 2 min daily. The amount of dextran released into the media wasmore » quantified. For in vivo studies, 0.25 mL ARSs were prepared as described previously and injected subcutaneously in the lower back of BALB/c mice. After polymerization, a subset of the implanted ARSs were exposed to FUS (as previously described). Animals were imaged longitudinally using a fluorescence imaging system to quantify the amount of dextran released from the ARSs. Results: In vitro: Over 6 days, +FUS displayed an 8.2-fold increase in dextran release compared to −FUS (−FUS: 2.7±0.6%; +FUS: 22.2±3.0%) for C{sub 6}F{sub 14} ARSs, and a 6.7-fold increase (−FUS: 5.0±0.8%; +FUS: 38.5±1.6%) for C{sub 5}F{sub 12}:C{sub 6}F{sub 14} ARSs. In vivo: +FUS displayed statistically greater dextran release compared to −FUS one day after implantation for C{sub 5}F{sub 12}:C{sub 6}F{sub 14} ARSs (−FUS: 55.1±1.5%; +FUS: 74.1±2.2%) and three days after implantation for C{sub 6}F{sub 14} ARSs (−FUS: 1.4±6.5%; +FUS: 30.4±5.4%). Conclusion: FUS enables non-invasive control of payload release from an ARS, which could benefit growth factor delivery for tissue regeneration. ARS are versatile due to their tunability (i.e. stiffness, emulsion composition, FUS pressure, FUS frequency, etc.) and can be modified to for optimal payload release. Future work will optimize ARS formulations for in vivo use to minimize payload release in the absence of FUS. This work was supported by NIH Grant R21 AR065010 (M.L. Fabiilli) and the Basic Radiologic Sciences Innovative Research Award (M.L. Fabiilli). A. Moncion is supported by the National Science Foundation Graduate Student Research Fellowship (Grant DGE 1256260).« less

EFFECT OF LIGHT-CURING UNITS AND ACTIVATION MODE ON POLYMERIZATION SHRINKAGE AND SHRINKAGE STRESS OF COMPOSITE RESINS

PubMed Central

Lopes, Lawrence Gonzaga; Franco, Eduardo Batista; Pereira, José Carlos; Mondelli, Rafael Francisco Lia

2008-01-01

The aim of this study was to evaluate the polymerization shrinkage and shrinkage stress of composites polymerized with a LED and a quartz tungsten halogen (QTH) light sources. The LED was used in a conventional mode (CM) and the QTH was used in both conventional and pulse-delay modes (PD). The composite resins used were Z100, A110, SureFil and Bisfil 2B (chemical-cured). Composite deformation upon polymerization was measured by the strain gauge method. The shrinkage stress was measured by photoelastic analysis. The polymerization shrinkage data were analyzed statistically using two-way ANOVA and Tukey test (p≤0.05), and the stress data were analyzed by one-way ANOVA and Tukey's test (p≤0.05). Shrinkage and stress means of Bisfil 2B were statistically significant lower than those of Z100, A110 and SureFil. In general, the PD mode reduced the contraction and the stress values when compared to CM. LED generated the same stress as QTH in conventional mode. Regardless of the activation mode, SureFil produced lower contraction and stress values than the other light-cured resins. Conversely, Z100 and A110 produced the greatest contraction and stress values. As expected, the chemically cured resin generated lower shrinkage and stress than the light-cured resins. In conclusion, The PD mode effectively decreased contraction stress for Z100 and A110. Development of stress in light-cured resins depended on the shrinkage value. PMID:19089287

Influence of light polymerization modes on degree of conversion and crosslink density of dental composites.

PubMed

da Silva, Eduardo Moreira; Poskus, Laiza Tatiana; Guimarães, José Guilherme Antunes; de Araújo Lima Barcellos, Alexandre; Fellows, Carlos Eduardo

2008-03-01

This study analyzed the influence of light polymerization modes on crosslink density (CD) and the degree of conversion (DC) of dental composites. A minifilled hybrid and a nanofilled dental composite were photoactivated with two light polymerization modes: Conventional-850 mW/cm2 for 20 s and Gradual-50 up to 1,000 mW/cm2 for 10 s+1,000 mW/cm2 for 10 s. DC was determined by the use of FT-Raman-spectrometer. A softening test, using Knoop diamond indentation, was carried out at the top and bottom of 2 mm thick dental composite disks, before and after storage in 100% ethanol for 24 h, in order to represent the amount of crosslink density. Data were analyzed by ANOVA and Student-Newman-Keuls' multiple range test (alpha=0.05). The DC was influenced by light polymerization modes, with Gradual mode presenting lower DC. On bottom surfaces, the nanofilled dental composite was more susceptible to softening by ethanol than minifilled hybrid, and gradual light polymerization of nanofilled dental composite resulted in more softening than when conventional light polymerization was used. The results suggest that nanofilled composites are capable undergoing more plasticization if applied in thick increments.

Engineering live cell surfaces with functional polymers via cytocompatible controlled radical polymerization

NASA Astrophysics Data System (ADS)

Niu, Jia; Lunn, David J.; Pusuluri, Anusha; Yoo, Justin I.; O'Malley, Michelle A.; Mitragotri, Samir; Soh, H. Tom; Hawker, Craig J.

2017-06-01

The capability to graft synthetic polymers onto the surfaces of live cells offers the potential to manipulate and control their phenotype and underlying cellular processes. Conventional grafting-to strategies for conjugating preformed polymers to cell surfaces are limited by low polymer grafting efficiency. Here we report an alternative grafting-from strategy for directly engineering the surfaces of live yeast and mammalian cells through cell surface-initiated controlled radical polymerization. By developing cytocompatible PET-RAFT (photoinduced electron transfer-reversible addition-fragmentation chain-transfer polymerization), synthetic polymers with narrow polydispersity (Mw/Mn < 1.3) could be obtained at room temperature in 5 minutes. This polymerization strategy enables chain growth to be initiated directly from chain-transfer agents anchored on the surface of live cells using either covalent attachment or non-covalent insertion, while maintaining high cell viability. Compared with conventional grafting-to approaches, these methods significantly improve the efficiency of grafting polymer chains and enable the active manipulation of cellular phenotypes.

Nanoparticles by spray drying using innovative new technology: the Büchi nano spray dryer B-90.

PubMed

Li, Xiang; Anton, Nicolas; Arpagaus, Cordin; Belleteix, Fabrice; Vandamme, Thierry F

2010-10-15

Spray drying technology is widely known and used to transform liquids (solutions, emulsions, suspension, slurries, pastes or even melts) into solid powders. Its main applications are found in the food, chemical and materials industries to enhance ingredient conservation, particle properties, powder handling and storage etc. However, spray drying can also be used for specific applications in the formulation of pharmaceuticals for drug delivery (e.g. particles for pulmonary delivery). Büchi is a reference in the development of spray drying technology, notably for laboratory scale devices. This study presents the Nano Spray Dryer B-90, a revolutionary new sprayer developed by Büchi, use of which can lower the size of the produced dried particles by an order of magnitude attaining submicron sizes. In this paper, results are presented with a panel of five representative polymeric wall materials (arabic gum, whey protein, polyvinyl alcohol, modified starch, and maltodextrin) and the potentials to encapsulate nano-emulsions, or to formulate nano-crystals (e.g. from furosemide) are also shown. Copyright © 2010 Elsevier B.V. All rights reserved.

Synthesis of nanosized (<20 nm) polymer particles by radical polymerization in miniemulsion employing in situ surfactant formation.

PubMed

Guo, Yi; Zetterlund, Per B

2011-10-18

A novel method for synthesis of ultrafine polymeric nanoparticles of diameters less than 20 nm has been developed. The method is based on miniemulsion polymerization exploiting combination of the in situ surfactant generation approach (whereby the surfactant is formed at the oil-water interface by reaction between an organic acid and a base) and ultrasonication. Conventional radical polymerization and nitroxide-mediated radical polymerization of styrene have been conducted in miniemulsion using oleic acid/potassium hydroxide, demonstrating that particles with diameters less than 20 nm can be obtained by this approach at surfactant contents much lower than traditionally required in microemulsion polymerizations. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performance impact of novel polymeric dyes in photoresist applications

NASA Astrophysics Data System (ADS)

Lu, Ping-Hung; Mehtsun, Salem; Sagan, John P.; Shan, Jianhui; Gonzalez, Eleazar; Ding, Shuji; Khanna, Dinesh N.

1999-06-01

Dye compounds are commonly used in photoresists as a low cost and effective way to control swing and/or standing wave effect caused by thin film interference as well as reflective notching by reflective light from highly reflective substrate and topography. Convention dyes are typically a monomeric compound with high absorptivity at the wavelength of exposure light and compatible with the resist system selected. Because of the monomeric nature, conventional dyes are relatively low in molecular weight hence their thermal stability and sublimination propensity has always been an issue of concern. We recently synthesize several highly thermal stable diazotized polymeric dyes. Their thermal properties as well as compatibility with resist system were investigated. The impact of polymeric dyes on the resists lithographic performance, swing reduction and reflective notching control are discussed.

Design and evaluation of a novel nanoparticulate-based formulation encapsulating a HIP complex of lysozyme.

PubMed

Gaudana, Ripal; Gokulgandhi, Mitan; Khurana, Varun; Kwatra, Deep; Mitra, Ashim K

2013-01-01

Formulation development of protein therapeutics using polymeric nanoparticles has found very little success in recent years. Major formulation challenges include rapid denaturation, susceptibility to lose bioactivity in presence of organic solvents and poor encapsulation in polymeric matrix. In the present study, we have prepared hydrophobic ion pairing (HIP) complex of lysozyme, a model protein, using dextran sulfate (DS) as a complexing polymer. We have optimized the process of formation and dissociation of HIP complex between lysozyme and DS. The effect of HIP complexation on enzymatic activity of lysozyme was also studied. Nanoparticles were prepared and characterized using spontaneous emulsion solvent diffusion method. Furthermore, we have also investigated release of lysozyme from nanoparticles along with its enzymatic activity. Results of this study indicate that nanoparticles can sustain the release of lysozyme without compromising its enzymatic activity. HIP complexation using a polymer may also be employed to formulate sustained release dosage forms of other macromolecules with enhanced encapsulation efficiency.

Estrone specific molecularly imprinted polymeric nanospheres: synthesis, characterization and applications for electrochemical sensor development.

PubMed

Congur, Gulsah; Senay, Hilal; Turkcan, Ceren; Canavar, Ece; Erdem, Arzum; Akgol, Sinan

2013-06-28

The aim of this study is (i) to prepare estrone-imprinted nanospheres (nano-EST-MIPs) and (ii) to integrate them into the electrochemical sensor as a recognition layer. N-methacryloyl-(l)-phenylalanine (MAPA) was chosen as the complexing monomer. Firstly, estrone (EST) was complexed with MAPA and the EST-imprinted poly(2-hyroxyethylmethacrylate-co-N-methacryloyl-(l)-phenylalanine) [EST-imprinted poly(HEMA-MAPA)] nanospheres were synthesized by surfactant- free emulsion polymerization method. The specific surface area of the EST-imprinted poly(HEMA-MAPA) nanospheres was found to be 1275 m2/g with a size of 163.2 nm in diameter. According to the elemental analysis results, the nanospheres contained 95.3 mmole MAPA/g nanosphere. The application of EST specific MIP nanospheres for the development of an electrochemical biosensor was introduced for the first time in our study by using electrochemical impedance spectroscopy (EIS) technique. This nano-MIP based sensor presented a great specificity and selectivity for EST.

The study of size and stability of n-butylcyanoacrylate nanocapsule suspensions encapsulating green grass fragrance

NASA Astrophysics Data System (ADS)

Zhu, G. Y.; Lin, C. T.; Chen, J. M.; Lei, D. M.; Zhu, G. X.

2018-01-01

Green grass fragrance has been widely used in many fields. However, fragrances are volatile compounds that do not last long. In order to prolong its odor, nanocapsules encapsulated green grass fragrance were prepared. The paper deals with the preparation of green grass fragrance nanocapsules by emulsion polymerization. N-butylcyanoacrylate (BCA) with excellent biocompatibility and biodegradability was used as encapsulant. The nanocapsule suspension systems were characterized and its stability was investigated. The physicochemical properties of polymeric nanocapsules (average diameter and polydispersity) were evaluated as a function of time to assess the system stability. The result showed that the system (containing 0.8% of green grass fragrance, with a polydispersity index (PDI) near 0.1 and an average diameter in the range of 20-30 nm) was an ideal state and relatively stable. Besides, the distinction of stability of three nanocapsule suspensions with different green grass fragrance content was also obvious from scanning electron microscopy (SEM).

Control of particle size by feed composition in the nanolatexes produced via monomer-starved semicontinuous emulsion copolymerization.

PubMed

Sajjadi, Shahriar

2015-05-01

Conventional batch and semicontinuous emulsion copolymerizations often produce large particles whose size cannot be easily correlated with the comonomer feed compositions, and are to some degree susceptible to composition drift. In contrast, we found that copolymer nanolatexes made via semicontinuous monomer-starved emulsion copolymerizations are featured with an average nanoparticle size being controlled by the feed composition, a high conversion achieved, and a high degree of particle composition uniformity. This was achieved because the rate of particle growth, during nucleation, was controlled by the rate of comonomer addition, and the copolymer composition, surfactant parking area on the particles, and nucleation efficiency determined by the comonomer feed composition. Two model systems, methyl methacrylate/styrene and vinyl acetate/butyl acrylate, with significant differences in water solubility were studied. Monomers were added to the aqueous solution of sodium dodecylsulfate and potassium persulfate at a low rate to achieve high instantaneous conversions. Copyright © 2015 Elsevier Inc. All rights reserved.

EFFECT OF CONVENTIONAL AND EXPERIMENTAL GINGIVAL RETRACTION SOLUTIONS ON THE TENSILE STRENGTH AND INHIBITION OF POLYMERIZATION OF FOUR TYPES OF IMPRESSION MATERIALS

PubMed Central

Sábio, Sérgio; Franciscone, Paulo Afonso; Mondelli, José

2008-01-01

In the present study, two types of tests (tensile strength test and polymerization inhibition test) were performed to evaluate the physical and chemical properties of four impression materials [a polysulfide (Permlastic), a polyether (Impregum), a condensation silicone (Xantopren) and a polyvinylsiloxane (Aquasil)] when polymerized in contact with of one conventional (Hemostop) and two experimental (Vislin and Afrin) gingival retraction solutions. For the tensile strength test, the impression materials were mixed and packed into a steel plate with perforations that had residues of the gingival retraction solutions. After polymerization, the specimens were tested in tensile strength in a universal testing machine. For the polymerization inhibition test, specimens were obtained after taking impressions from a matrix with perforations that contained 1 drop of the gingival retraction solutions. Two independent examiners decided on whether or not impression material remnants remained unpolymerized, indicating interference of the chemical solutions. Based on the analysis of the results of both tests, the following conclusions were reached: 1. The tensile strength of the polysulfide decreased after contact with Hemostop and Afrin. 2. None of the chemical solutions inhibited the polymerization of the polysulfide; 3. The polyether presented lower tensile strength after polymerization in contact with the three gingival retraction agents; 4. The polyether had its polymerization inhibited only by Hemostop; 5. None of the chemical solutions affected the tensile strength of the condensation silicone; 6. Only Hemostop inhibited the polymerization of the condensation silicone; 7. The polyvinylsiloxane specimens polymerized in contact with Hemostop had significantly lower tensile strength; 8. Neither of the chemical solutions (Afrin and Vislin) affected the tensile strength of the polyvinylsiloxane and the condensation silicone; 9. Results of the tensile strength and polymerization inhibition tests suggest that Vislin can be used as substance of gingival retraction without affecting the tested properties of four impression materials. PMID:19089261

Effect of conventional and experimental gingival retraction solutions on the tensile strength and inhibition of polymerization of four types of impression materials.

PubMed

Sábio, Sérgio; Franciscone, Paulo Afonso; Mondelli, José

2008-01-01

In the present study, two types of tests (tensile strength test and polymerization inhibition test) were performed to evaluate the physical and chemical properties of four impression materials [a polysulfide (Permlastic), a polyether (Impregum), a condensation silicone (Xantopren) and a polyvinylsiloxane (Aquasil)] when polymerized in contact with of one conventional (Hemostop) and two experimental (Vislin and Afrin) gingival retraction solutions. For the tensile strength test, the impression materials were mixed and packed into a steel plate with perforations that had residues of the gingival retraction solutions. After polymerization, the specimens were tested in tensile strength in a universal testing machine. For the polymerization inhibition test, specimens were obtained after taking impressions from a matrix with perforations that contained 1 drop of the gingival retraction solutions. Two independent examiners decided on whether or not impression material remnants remained unpolymerized, indicating interference of the chemical solutions. Based on the analysis of the results of both tests, the following conclusions were reached: 1. The tensile strength of the polysulfide decreased after contact with Hemostop and Afrin. 2. None of the chemical solutions inhibited the polymerization of the polysulfide; 3. The polyether presented lower tensile strength after polymerization in contact with the three gingival retraction agents; 4. The polyether had its polymerization inhibited only by Hemostop; 5. None of the chemical solutions affected the tensile strength of the condensation silicone; 6. Only Hemostop inhibited the polymerization of the condensation silicone; 7. The polyvinylsiloxane specimens polymerized in contact with Hemostop had significantly lower tensile strength; 8. Neither of the chemical solutions (Afrin and Vislin) affected the tensile strength of the polyvinylsiloxane and the condensation silicone; 9. Results of the tensile strength and polymerization inhibition tests suggest that Vislin can be used as substance of gingival retraction without affecting the tested properties of four impression materials.

Bacterial adhesion on conventional and self-ligating metallic brackets after surface treatment with plasma-polymerized hexamethyldisiloxane

PubMed Central

Tupinambá, Rogerio Amaral; Claro, Cristiane Aparecida de Assis; Pereira, Cristiane Aparecida; Nobrega, Celestino José Prudente; Claro, Ana Paula Rosifini Alves

2017-01-01

ABSTRACT Introduction: Plasma-polymerized film deposition was created to modify metallic orthodontic brackets surface properties in order to inhibit bacterial adhesion. Methods: Hexamethyldisiloxane (HMDSO) polymer films were deposited on conventional (n = 10) and self-ligating (n = 10) stainless steel orthodontic brackets using the Plasma-Enhanced Chemical Vapor Deposition (PECVD) radio frequency technique. The samples were divided into two groups according to the kind of bracket and two subgroups after surface treatment. Scanning Electron Microscopy (SEM) analysis was performed to assess the presence of bacterial adhesion over samples surfaces (slot and wings region) and film layer integrity. Surface roughness was assessed by Confocal Interferometry (CI) and surface wettability, by goniometry. For bacterial adhesion analysis, samples were exposed for 72 hours to a Streptococcus mutans solution for biofilm formation. The values obtained for surface roughness were analyzed using the Mann-Whitney test while biofilm adhesion were assessed by Kruskal-Wallis and SNK test. Results: Significant statistical differences (p< 0.05) for surface roughness and bacterial adhesion reduction were observed on conventional brackets after surface treatment and between conventional and self-ligating brackets; no significant statistical differences were observed between self-ligating groups (p> 0.05). Conclusion: Plasma-polymerized film deposition was only effective on reducing surface roughness and bacterial adhesion in conventional brackets. It was also noted that conventional brackets showed lower biofilm adhesion than self-ligating brackets despite the absence of film. PMID:28902253

Poly(lactic-co-glycolic acid) devices: Production and applications for sustained protein delivery.

PubMed

Lee, Parker W; Pokorski, Jonathan K

2018-03-13

Injectable or implantable poly(lactic-co-glycolic acid) (PLGA) devices for the sustained delivery of proteins have been widely studied and utilized to overcome the necessity of repeated administrations for therapeutic proteins due to poor pharmacokinetic profiles of macromolecular therapies. These devices can come in the form of microparticles, implants, or patches depending on the disease state and route of administration. Furthermore, the release rate can be tuned from weeks to months by controlling the polymer composition, geometry of the device, or introducing additives during device fabrication. Slow-release devices have become a very powerful tool for modern medicine. Production of these devices has initially focused on emulsion-based methods, relying on phase separation to encapsulate proteins within polymeric microparticles. Process parameters and the effect of additives have been thoroughly researched to ensure protein stability during device manufacturing and to control the release profile. Continuous fluidic production methods have also been utilized to create protein-laden PLGA devices through spray drying and electrospray production. Thermal processing of PLGA with solid proteins is an emerging production method that allows for continuous, high-throughput manufacturing of PLGA/protein devices. Overall, polymeric materials for protein delivery remain an emerging field of research for the creation of single administration treatments for a wide variety of disease. This review describes, in detail, methods to make PLGA devices, comparing traditional emulsion-based methods to emerging methods to fabricate protein-laden devices. This article is categorized under: Biology-Inspired Nanomaterials > Protein and Virus-Based Structures Implantable Materials and Surgical Technologies > Nanomaterials and Implants Biology-Inspired Nanomaterials > Peptide-Based Structures. © 2018 Wiley Periodicals, Inc.

Long-term biobarriers to plant and animal intrusions of uranium tailings. [24% trifluralin, 18% carbon black, and 58% polymer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cline, J.F.; Burton, F.G.; Cataldo, D.A.

1982-09-01

The objective of this project was to develop and evaluate the effectiveness of physical and chemical barriers designed to prevent plant and animal breachment of uranium mill tailings containment systems for an extended period of time. A polymeric carrier/biocide delivery system was developed and tested in the laboratory, greenhouse and field. A continuous flow technique was established to determine the release rates of the biocides from the PCD systems; polymeric carrier specifications were established. Studies were conducted to determine effective biocide concentrations required to produce a phytotoxic response and the relative rates of phytotoxin degradation resulting from chemical and biologicalmore » breakdown in soils. The final PCD system developed was a pelletized system containing 24% trifluralin, 18% carbon black and 58% polymer. Pellets were placed in the soil at the Grand Junction U-tailings site at one in. and two in. intervals. Data obtained in the field determined that the pellets released enough herbicide to the soil layer to stop root elongation past the barrier. Physical barriers to subsurface movement of burrowing animals were investigated. Small crushed stone (1 to 1 1/2 in. diameter) placed over asphalt emulsion and multilayer soil seals proved effective as barriers to a small mammal (ground squirrels) but were not of sufficient size to stop a larger animal (the prairie dog). No penetrations were made through the asphalt emulsion or the clay layer of the multilayer soil seals by either of the two mammals tested. A literature survey was prepared and published on the burrowing habits of the animals that may be found at U-tailings sites.« less

Factors affecting emulsion stability and quality of oil recovered from enzyme-assisted aqueous extraction of soybeans.

PubMed

Jung, S; Maurer, D; Johnson, L A

2009-11-01

The objectives of the present study were to assess how the stability of the emulsion recovered from aqueous extraction processing of soybeans was affected by characteristics of the starting material and extraction and demulsification conditions. Adding endopeptidase Protex 6L during enzyme-assisted aqueous extraction processing (EAEP) of extruded soybean flakes was vital to obtaining emulsions that were easily demulsified with enzymes. Adding salt (up to 1.5 mM NaCl or MgCl(2)) during extraction and storing extruded flakes before extraction at 4 and 30 degrees C for up to 3 months did not affect the stabilities of emulsions recovered from EAEP of soy flour, flakes and extruded flakes. After demulsification, highest free oil yield was obtained with EAEP of extruded flakes, followed by flour and then flakes. The same protease used for the extraction step was used to demulsify the EAEP cream emulsion from extruded full-fat soy flakes at concentrations ranging from 0.03% to 2.50% w/w, incubation times ranging from 2 to 90 min, and temperatures of 25, 50 or 65 degrees C. Highest free oil recoveries were achieved at high enzyme concentrations, mild temperatures, and short incubation times. Both the nature of enzyme (i.e., protease and phospholipase), added alone or as a cocktail, concentration of enzymes (0.5% vs. 2.5%) and incubation time (1 vs. 3 h), use during the extraction step, and nature of enzyme added for demulsifying affected free oil yield. The free oil recovered from EAEP of extruded flakes contained less phosphorus compared with conventional hexane-extracted oil. The present study identified conditions rendering the emulsion less stable, which is critical to increasing free oil yield recovered during EAEP of soybeans, an environmentally friendly alternative processing method to hexane extraction.

In vitro comparison of autoclave polymerization on the transverse strength of denture base resins.

PubMed

Durkan, Rukiye; Ozel, Mehmet Birol; Bağiş, Bora; Usanmaz, Ali

2008-07-01

The aim of this study was to determine the effect of autoclave polymerization on the transverse strength of denture base polymers. To this end, 30 rectangular test specimens were fabricated of two heat-polymerized denture base polymers. The test groups were: (I) control, i.e., conventional water bath to polymerize resins by heat at 100 degrees C for 30 minutes; (II) autoclave polymerization at 60 degrees C for 30 minutes followed by 130 degrees C for 10 minutes; and (III) autoclave polymerization at 60 degrees C for 30 minutes followed by 130 degrees C for 20 minutes. The specimens were tested with three-point bending test at a crosshead speed of 5 mm/min. It was revealed that the transverse strength of specimens increased with statistical significance when the autoclave was used for polymerization.

Gelation of Soy Milk with Hagfish Exudate Creates a Flocculated and Fibrous Emulsion- and Particle Gel

PubMed Central

Böni, Lukas; Rühs, Patrick A.; Windhab, Erich J.; Fischer, Peter; Kuster, Simon

2016-01-01

Hagfish slime is an ultra dilute, elastic and cohesive hydrogel that deploys within milliseconds in cold seawater from a glandularly secreted exudate. The slime is made of long keratin-like fibers and mucin-like glycoproteins that span a network which entraps water and acts as a defense mechanism against predators. Unlike other hydrogels, the slime only confines water physically and is very susceptible to mechanical stress, which makes it unsuitable for many processing operations and potential applications. Despite its huge potential, little work has been done to improve and functionalize the properties of this hydrogel. To address this shortcoming, hagfish exudate was mixed with a soy protein isolate suspension (4% w/v) and with a soy emulsion (commercial soy milk) to form a more stable structure and combine the functionalities of a suspension and emulsion with those of the hydrogel. Hagfish exudate interacted strongly with the soy systems, showing a markedly increased viscoelasticity and water retention. Hagfish mucin was found to induce a depletion and bridging mechanism, which caused the emulsion and suspension to flocculate, making “soy slime”, a cohesive and cold-set emulsion- and particle gel. The flocculation network increases viscoelasticity and substantially contributes to liquid retention by entrapping liquid in the additional confinements between aggregated particles and protein fibers. Because the mucin-induced flocculation resembles the salt- or acid-induced flocculation in tofu curd production, the soy slime was cooked for comparison. The cooked soy slime was similar to conventional cooked tofu, but possessed a long-range cohesiveness from the fibers. The fibrous, cold-set, and curd-like structure of the soy slime represents a novel way for a cold coagulation and fiber incorporation into a suspension or emulsion. This mechanism could be used to efficiently gel functionalized emulsions or produce novel tofu-like structured food products. PMID:26808048

Gelation of Soy Milk with Hagfish Exudate Creates a Flocculated and Fibrous Emulsion- and Particle Gel.

PubMed

Böni, Lukas; Rühs, Patrick A; Windhab, Erich J; Fischer, Peter; Kuster, Simon

2016-01-01

Hagfish slime is an ultra dilute, elastic and cohesive hydrogel that deploys within milliseconds in cold seawater from a glandularly secreted exudate. The slime is made of long keratin-like fibers and mucin-like glycoproteins that span a network which entraps water and acts as a defense mechanism against predators. Unlike other hydrogels, the slime only confines water physically and is very susceptible to mechanical stress, which makes it unsuitable for many processing operations and potential applications. Despite its huge potential, little work has been done to improve and functionalize the properties of this hydrogel. To address this shortcoming, hagfish exudate was mixed with a soy protein isolate suspension (4% w/v) and with a soy emulsion (commercial soy milk) to form a more stable structure and combine the functionalities of a suspension and emulsion with those of the hydrogel. Hagfish exudate interacted strongly with the soy systems, showing a markedly increased viscoelasticity and water retention. Hagfish mucin was found to induce a depletion and bridging mechanism, which caused the emulsion and suspension to flocculate, making "soy slime", a cohesive and cold-set emulsion- and particle gel. The flocculation network increases viscoelasticity and substantially contributes to liquid retention by entrapping liquid in the additional confinements between aggregated particles and protein fibers. Because the mucin-induced flocculation resembles the salt- or acid-induced flocculation in tofu curd production, the soy slime was cooked for comparison. The cooked soy slime was similar to conventional cooked tofu, but possessed a long-range cohesiveness from the fibers. The fibrous, cold-set, and curd-like structure of the soy slime represents a novel way for a cold coagulation and fiber incorporation into a suspension or emulsion. This mechanism could be used to efficiently gel functionalized emulsions or produce novel tofu-like structured food products.

Ceramic microparticles and capsules via microfluidic processing of a preceramic polymer

PubMed Central

Ye, Congwang; Chen, Anthony; Colombo, Paolo; Martinez, Carlos

2010-01-01

We have developed a robust technique to fabricate monodispersed solid and porous ceramic particles and capsules from single and double emulsion drops composed of silsesquioxane preceramic polymer. A microcapillary microfluidic device was used to generate the monodispersed drops. In this device, two round capillaries are aligned facing each other inside a square capillary. Three fluids are needed to generate the double emulsions. The inner fluid, which flows through the input capillary, and the middle fluid, which flows through the void space between the square and inner fluid capillaries, form a coaxial co-flow in a direction that is opposite to the flow of the outer fluid. As the three fluids are forced through the exit capillary, the inner and middle fluids break into monodispersed double emulsion drops in a single-step process, at rates of up to 2000 drops s−1. Once the drops are generated, the silsesquioxane is cross-linked in solution and the cross-linked particles are dried and pyrolysed in an inert atmosphere to form oxycarbide glass particles. Particles with diameters ranging from 30 to 180 µm, shell thicknesses ranging from 10 to 50 µm and shell pore diameters ranging from 1 to 10 µm were easily prepared by changing fluid flow rates, device dimensions and fluid composition. The produced particles and capsules can be used in their polymeric state or pyrolysed to ceramic. This technique can be extended to other preceramic polymers and can be used to generate unique core–shell multimaterial particles. PMID:20484226

Bioactive Hybrid Particles from Poly(D,L-lactide-co-glycolide) Nanoparticle Stabilized Lipid Droplets.

PubMed

Joyce, Paul; Whitby, Catherine P; Prestidge, Clive A

2015-08-12

Biodegradable and bioactive hybrid particles composed of poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles and medium-chain triglycerides were prepared by spray drying lipid-in-water emulsions stabilized by PLGA nanoparticles, to form PLGA-lipid hybrid (PLH) microparticles approximately 5 μm in mean diameter. The nanoparticle stabilizer was varied and mannitol was also incorporated during the preparation to investigate the effect of stabilizer charge and cryoprotectant content on the particle microstructure. An in vitro lipolysis model was used to demonstrate the particles' bioactivity by manipulating the digestion kinetics of encapsulated lipid by pancreatic lipase in simulated gastrointestinal fluid. Lipid digestion kinetics were enhanced in PLH and PLGA-lipid-mannitol hybrid (PLMH) microparticles for both stabilizers, compared to a coarse emulsion, in biorelevant media. An optimal digestion rate was observed for the negatively charged PLMH system, evidenced by a 2-fold increase in the pseudo-first-order rate constant compared to a coarse emulsion. Improved microparticle redispersion, probed by dual dye confocal fluorescence microscopy, increased the available surface area of lipid for lipase adsorption, enhancing digestion kinetics. Thereby, lipase action was controlled in hybrid microparticles by altering the surface charge and carbohydrate content. Our results demonstrate that bioactive microparticles composed of versatile and biodegradable polymeric particles and oil droplets have great potential for use in smart food and nutrient delivery, as well as safer and more efficacious oral delivery of drugs and drug combinations.

Ceramic microparticles and capsules via microfluidic processing of a preceramic polymer.

PubMed

Ye, Congwang; Chen, Anthony; Colombo, Paolo; Martinez, Carlos

2010-08-06

We have developed a robust technique to fabricate monodispersed solid and porous ceramic particles and capsules from single and double emulsion drops composed of silsesquioxane preceramic polymer. A microcapillary microfluidic device was used to generate the monodispersed drops. In this device, two round capillaries are aligned facing each other inside a square capillary. Three fluids are needed to generate the double emulsions. The inner fluid, which flows through the input capillary, and the middle fluid, which flows through the void space between the square and inner fluid capillaries, form a coaxial co-flow in a direction that is opposite to the flow of the outer fluid. As the three fluids are forced through the exit capillary, the inner and middle fluids break into monodispersed double emulsion drops in a single-step process, at rates of up to 2000 drops s(-1). Once the drops are generated, the silsesquioxane is cross-linked in solution and the cross-linked particles are dried and pyrolysed in an inert atmosphere to form oxycarbide glass particles. Particles with diameters ranging from 30 to 180 microm, shell thicknesses ranging from 10 to 50 microm and shell pore diameters ranging from 1 to 10 microm were easily prepared by changing fluid flow rates, device dimensions and fluid composition. The produced particles and capsules can be used in their polymeric state or pyrolysed to ceramic. This technique can be extended to other preceramic polymers and can be used to generate unique core-shell multimaterial particles.

The metabolic consequences of infusing emulsions containing medium chain triglycerides for parenteral nutrition: a comparative study with conventional lipid.

PubMed Central

Dennison, A. R.; Ball, M.; Crowe, P. J.; White, K.; Hands, L.; Watkins, R. M.; Kettlewell, M.

1986-01-01

In order to test the hypothesis that medium chain triglycerides (MCT's) are a safe and potentially superior energy source during parenteral nutrition 13 patients were entered into a randomised cross over trial. They received either a long chain triglyceride emulsion (LCT) or a 50% medium chain (MCT)/50% LCT mixture as part of their energy supply. Nitrogen balance was significantly better when MCT/LCT was infused and the greater levels of plasma ketones and lower plasma triglyceride levels suggested that MCT was more readily metabolised in these patients. Routine haematology, biochemistry and liver function tests gave no indication of harmful side effects from MCT. PMID:3089123

Modular in situ-Functionalization Strategy: Multicomponent Polymerization via Palladium/Norbornene Cooperative Catalysis.

PubMed

Yoon, Ki-Young; Dong, Guangbin

2018-05-23

Herein, we report the palladium/norbornene cooperatively catalyzed polymerization, which simplifies synthesis of functional aromatic polymers, including conjugated polymers. Specifically, an A2B2C-type multicomponent polymerization is developed using ortho-amination/ipso-alkynylation reaction for preparing various amine-functionalized arylacetylene-containing polymers. Within a single catalytic cycle, the amine side-chains are site-selectively installed in situ via C-H activation during the polymerization process, which represents a major difference from conventional cross-coupling polymerizations. This in situ-functionalization strategy enables modular incorporation of functional side-chains from simple monomers, thereby conveniently affording a diverse range of functional polymers. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polymeric hydrogels for novel contact lens-based ophthalmic drug delivery systems: a review.

PubMed

Xinming, Li; Yingde, Cui; Lloyd, Andrew W; Mikhalovsky, Sergey V; Sandeman, Susan R; Howel, Carol A; Liewen, Liao

2008-04-01

Only about 5% of drugs administrated by eye drops are bioavailable, and currently eye drops account for more than 90% of all ophthalmic formulations. The bioavailability of ophthalmic drugs can be improved by a soft contact lens-based ophthalmic drug delivery system. Several polymeric hydrogels have been investigated for soft contact lens-based ophthalmic drug delivery systems: (i) polymeric hydrogels for conventional contact lens to absorb and release ophthalmic drugs; (ii) polymeric hydrogels for piggyback contact lens combining with a drug plate or drug solution; (iii) surface-modified polymeric hydrogels to immobilize drugs on the surface of contact lenses; (iv) polymeric hydrogels for inclusion of drugs in a colloidal structure dispersed in the lens; (v) ion ligand-containing polymeric hydrogels; (vi) molecularly imprinted polymeric hydrogels which provide the contact lens with a high affinity and selectivity for a given drug. Polymeric hydrogels for these contact lens-based ophthalmic drug delivery systems, their advantages and drawbacks are critically analyzed in this review.

Hydrolase stabilization via entanglement in poly(propylene sulfide) nanoparticles: stability towards reactive oxygen species.

PubMed

Allen, Brett L; Johnson, Jermaine D; Walker, Jeremy P

2012-07-27

In the advancement of green syntheses and sustainable reactions, enzymatic biocatalysis offers extremely high reaction rates and selectivity that goes far beyond the reach of chemical catalysts; however, these enzymes suffer from typical environmental constraints, e.g. operational temperature, pH and tolerance to oxidative environments. A common hydrolase enzyme, diisopropylfluorophosphatase (DFPase, EC 3.1.8.2), has demonstrated a pronounced efficacy for the hydrolysis of a variety of substrates for potential toxin remediation, but suffers from the aforementioned limitations. As a means to enhance DFPase's stability in oxidative environments, enzymatic covalent immobilization within the polymeric matrix of poly(propylene sulfide) (PPS) nanoparticles was performed. By modifying the enzyme's exposed lysine residues via thiolation, DFPase is utilized as a comonomer/crosslinker in a mild emulsion polymerization. The resultant polymeric polysulfide shell acts as a 'sacrificial barrier' by first oxidizing to polysulfoxides and polysulfones, rendering DFPase in an active state. DFPase-PPS nanoparticles thus retain activity upon exposure to as high as 50 parts per million (ppm) of hypochlorous acid (HOCl), while native DFPase is observed as inactive at 500 parts per billion (ppb). This trend is also confirmed by enzyme-generated (chloroperoxidase (CPO), EC 1.11.1.10) reactive oxygen species (ROS) including both HOCl (3 ppm) and ClO(2) (100 ppm).

Occlusion of Sulfate-Based Diblock Copolymer Nanoparticles within Calcite: Effect of Varying the Surface Density of Anionic Stabilizer Chains.

PubMed

Ning, Yin; Fielding, Lee A; Ratcliffe, Liam P D; Wang, Yun-Wei; Meldrum, Fiona C; Armes, Steven P

2016-09-14

Polymerization-induced self-assembly (PISA) offers a highly versatile and efficient route to a wide range of organic nanoparticles. In this article, we demonstrate for the first time that poly(ammonium 2-sulfatoethyl methacrylate)-poly(benzyl methacrylate) [PSEM-PBzMA] diblock copolymer nanoparticles can be prepared with either a high or low PSEM stabilizer surface density using either RAFT dispersion polymerization in a 2:1 v/v ethanol/water mixture or RAFT aqueous emulsion polymerization, respectively. We then use these model nanoparticles to gain new insight into a key topic in materials chemistry: the occlusion of organic additives into inorganic crystals. Substantial differences are observed for the extent of occlusion of these two types of anionic nanoparticles into calcite (CaCO3), which serves as a suitable model host crystal. A low PSEM stabilizer surface density leads to uniform nanoparticle occlusion within calcite at up to 7.5% w/w (16% v/v), while minimal occlusion occurs when using nanoparticles with a high PSEM stabilizer surface density. This counter-intuitive observation suggests that an optimum anionic surface density is required for efficient occlusion, which provides a hitherto unexpected design rule for the incorporation of nanoparticles within crystals.

Comparative real-time study of cellular uptake of a formulated conjugated linolenic acid rich nano and conventional macro emulsions and their bioactivity in ex vivo models for parenteral applications.

PubMed

Paul, Debjyoti; Mukherjee, Sayani; Chakraborty, Rajarshi; Mallick, Sanjaya K; Dhar, Pubali

2015-02-01

The objective of the present study was to fabricate and monitor real-time, impact of a stable conjugated linolenic acid, α-eleostearic acid (ESA) rich nanoemulsion (NE) formulation (d < 200 nm) vis-à-vis ESA conventional emulsion (CE) system in ex vivo systems against both endogenous and exogenous reactive oxygen species (ROS). Accordingly, stable nanoemulsion formulation of ESA was engineered with the aid of bitter melon seed oil and non-toxic excipients. Morphology and particle size of the emulsion formulations were studied to validate stability. The real-time rapid uptake of the ESA NE and its increased prophylactic efficacy against induced endogenous and exogenous ROS in terms of cell viability and membrane integrity was evaluated flow-cytometrically and with fluorescence microscopic analysis of different primary cells. It was found that the fabricated non-toxic ESA NE had stable parameters (hydrodynamic mean diameter, particle size distribution and zeta potential) for over 12 weeks. Further, ESA NE at a concentration of ∼ 70 μM exhibited maximum efficacy in protecting cells from oxidative damage against both endogenous and exogenous ROS in lymphocytes and hepatocytes as compared to its corresponding presence in the CE formulation. This study provides a real-time empirical evidence on the influence of nano formulation in enhancing bioavailability and antioxidative properties of ESA. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis of nanostructured materials in inverse miniemulsions and their applications.

PubMed

Cao, Zhihai; Ziener, Ulrich

2013-11-07

Polymeric nanogels, inorganic nanoparticles, and organic-inorganic hybrid nanoparticles can be prepared via the inverse miniemulsion technique. Hydrophilic functional cargos, such as proteins, DNA, and macromolecular fluoresceins, may be conveniently encapsulated in these nanostructured materials. In this review, the progress of inverse miniemulsions since 2000 is summarized on the basis of the types of reactions carried out in inverse miniemulsions, including conventional free radical polymerization, controlled/living radical polymerization, polycondensation, polyaddition, anionic polymerization, catalytic oxidation reaction, sol-gel process, and precipitation reaction of inorganic precursors. In addition, the applications of the nanostructured materials synthesized in inverse miniemulsions are also reviewed.

Separation of oil-water-sludge emulsions coming from palm oil mill process through microwave techniques.

PubMed

Pérez-Páez, Rocío; Catalá-Civera, José Manuel; García-Baños, Beatriz; Castillo, Edgar F; Bastos, Johanna M; Zambrano, Luz S

2008-01-01

The palm oil mills extraction process requires the separation of oil-water-sludge emulsions. For this purpose, the use of sedimentation and/or centrifugation techniques have been required until now. However, significant losses persist in different process flows and new methods are needed to further decrease them, such as methods based on electromagnetic waves application. In the study, emulsions obtained from two flow processes, namely press liquor stream (PL) and recovered stream of the centrifugal step (RC), were exposed to microwave radiation with different exposure times. In the case of the press liquor stream, different oil/water dilution ratios were also studied. The sedimentation speed and efficiency were studied for the irradiated samples and compared to those obtained for the same fluids with no radiation. Also, chromatographic tests were performed on the recovered oil to determine the effect on the oil quality after microwave radiation. The obtained results allow us to conclude that microwave exposure during periods below 1 minute lead to better sedimentation speed and efficiency. It was observed that microwaves facilitate the break of the charges and polarities balances in the emulsions at considerably lower temperatures than the corresponding in the conventional process, without affecting the recovered oil quality.

Prevention and reversal of intestinal failure-associated liver disease in premature infants with short bowel syndrome using intravenous fish oil in combination with omega-6/9 lipid emulsions.

PubMed

Lilja, Helene Engstrand; Finkel, Yigael; Paulsson, Mattias; Lucas, Steven

2011-07-01

Although premature infants with short bowel syndrome are at the highest risk of developing intestinal failure-associated liver disease (IFALD), they have great capacity for intestinal growth and adaptation if IFALD can be prevented. Conventional soybean oil-based intravenous lipid emulsions have been associated with IFALD. This study presents data on 5 premature neonates with short bowel syndrome treated with a combination of parenteral fish oil- and olive/soybean-based lipid emulsion for periods ranging between 7 and 17 months. Despite an enteral tolerance of less than 50% in 4 of these patients during their first year of life, direct bilirubin levels normalized while on this combination of ClinOleic (Baxter, Maurepas, France)/Omegaven (Fresenius Kabi, Bad Homburg, Germany) at a 1:1 ratio. None of our patients developed irreversible IFALD even though all of them were premature, had undergone multiple major surgical procedures, and had experienced several episodes of sepsis. Thus far, we have not seen any adverse effects of this mixed lipid emulsion in these preterm infants. All 5 patients are growing and developing well and have normal liver function. Copyright © 2011 Elsevier Inc. All rights reserved.

Microparticles Produced by the Hydrogel Template Method for Sustained Drug Delivery

PubMed Central

Lu, Ying; Sturek, Michael; Park, Kinam

2014-01-01

Polymeric microparticles have been used widely for sustained drug delivery. Current methods of microparticle production can be improved by making homogeneous particles in size and shape, increasing the drug loading, and controlling the initial burst release. In the current study, the hydrogel template method was used to produce homogeneous poly(lactide-co-glycolide) (PLGA) microparticles and to examine formulation and process-related parameters. Poly(vinyl alcohol) (PVA) was used to make hydrogel templates. The parameters examined include PVA molecular weight, type of PLGA (as characterized by lactide content, inherent viscosity), polymer concentration, drug concentration and composition of solvent system. Three model compounds studied were risperidone, methylprednisolone acetate and paclitaxel. The ability of the hydrogel template method to produce microparticles with good conformity to template was dependent on molecular weight of PVA and viscosity of the PLGA solution. Drug loading and encapsulation efficiency were found to be influenced by PLGA lactide content, polymer concentration and composition of the solvent system. The drug loading and encapsulation efficiency were 28.7% and 82% for risperidone, 31.5% and 90% for methylprednisolone acetate, and 32.2 % and 92 % for paclitaxel, respectively. For all three drugs, release was sustained for weeks, and the in vitro release profile of risperidone was comparable to that of microparticles prepared using the conventional emulsion method. The hydrogel template method provides a new approach of manipulating microparticles. PMID:24333903

Novel Biocompatible Thermoresponsive Poly(N-vinyl Caprolactam)/Clay Nanocomposite Hydrogels with Macroporous Structure and Improved Mechanical Characteristics.

PubMed

Shi, Kun; Liu, Zhuang; Yang, Chao; Li, Xiao-Ying; Sun, Yi-Min; Deng, Yi; Wang, Wei; Ju, Xiao-Jie; Xie, Rui; Chu, Liang-Yin

2017-07-05

Poly(N-vinyl caprolactam) (PVCL) hydrogels usually suffer from the imporous structure and poor mechanical characteristics as well as the toxicity of cross-linkers, although PVCL itself is biocompatible. In this paper, novel biocompatible thermoresponsive poly(N-vinyl caprolactam)/clay nanocomposite (PVCL-Clay) hydrogels with macroporous structure and improved mechanical characteristics are developed for the first time. The macroporosity in the hydrogel is introduced by using Pickering emulsions as templates, which contain N-vinyl caprolactam (VCL) monomer as dispersed phase and clay sheets as stabilizers at the interface. After polymerization, macropores are formed inside the hydrogels with the residual unreacted VCL droplets as templates. The three-dimensional PVCL polymer networks are cross-linked by the clay nanosheets. Due to the nanocomposite structure, the hydrogel exhibits better mechanical characteristics in comparison to the conventional PVCL hydrogels cross-linked by N,N'-methylene diacrylamide (BIS). The prepared PVCL-Clay hydrogel possesses remarkable temperature-responsive characteristics with a volume phase transition temperature (VPTT) around 35 °C, and provides a feasible platform for cell culture. With macroporous structure and good mechanical characteristics as well as flexible assembly performance, the proposed biocompatible thermoresponsive PVCL-Clay nanocomposite hydrogels are ideal material candidates for biomedical, analytical, and other applications such as entrapment of enzymes, cell culture, tissue engineering, and affinity and displacement chromatography.

Process evaluation and in vitro selectivity analysis of aptamer-drug polymeric formulation for targeted pharmaceutical delivery.

PubMed

Tan, Kei X; Lau, Sie Yon; Danquah, Michael K

2018-05-01

Targeted drug delivery is a promising strategy to promote effective delivery of conventional and emerging pharmaceuticals. The emergence of aptamers as superior targeting ligands to direct active drug molecules specifically to desired malignant cells has created new opportunities to enhance disease therapies. The application of biodegradable polymers as delivery carriers to develop aptamer-navigated drug delivery system is a promising approach to effectively deliver desired drug dosages to target cells. This study reports the development of a layer-by-layer aptamer-mediated drug delivery system (DPAP) via a w/o/w double emulsion technique homogenized by ultrasonication or magnetic stirring. Experimental results showed no significant differences in the biophysical characteristics of DPAP nanoparticles generated using the two homogenization techniques. The DPAP formulation demonstrated a strong targeting performance and selectivity towards its target receptor molecules in the presence of non-targets. The DPAP formulation demonstrated a controlled and sustained drug release profile under the conditions of pH 7 and temperature 37 °C. Also, the drug release rate of DPAP formulation was successfully accelerated under an endosomal acidic condition of ∼pH 5.5, indicating the potential to enhance drug delivery within the endosomal micro-environment. The findings from this work are useful to understanding polymer-aptamer-drug relationship and their impact on developing effective targeted delivery systems. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Polymerization shrinkage of a dental resin composite determined by a fiber optic Fizeau interferometer

NASA Astrophysics Data System (ADS)

Arenas, Gustavo; Noriega, Sergio; Vallo, Claudia; Duchowicz, Ricardo

2007-03-01

A fiber optic sensing method based on a Fizeau-type interferometric scheme was employed for monitoring linear polymerization shrinkage in dental restoratives. This technique offers several advantages over the conventional methods of measuring polymerization contraction. This simple, compact, non-invasive and self-calibrating system competes with both conventional and other high-resolution bulk interferometric techniques. In this work, an analysis of the quality of interference signal and fringes visibility was performed in order to characterize their resolution and application range. The measurements of percent linear contraction as a function of the sample thickness were carried out in this study on two dental composites: Filtek P60 (3M ESPE) Posterior Restorer and Filtek Z250 (3M ESPE) Universal Restorer. The results were discussed with respect to others obtained employing alternative techniques.

Castable three-dimensional stationary phase for electric field-driven applications

DOEpatents

Shepodd, Timothy J.; Whinnery, Jr., Leroy; Even, Jr., William R.

2005-01-25

A polymer material useful as the porous dielectric medium for microfluidic devices generally and electrokinetic pumps in particular. The polymer material is produced from an inverse (water-in-oil) emulsion that creates a 3-dimensional network characterized by small pores and high internal volume, characteristics that are particularly desirable for the dielectric medium for electrokinetic pumps. Further, the material can be cast-to-shape inside a microchannel. The use of bifunctional monomers provides for charge density within the polymer structure sufficient to support electroosmotic flow. The 3-dimensional polymeric material can also be covalently bound to the channel walls thereby making it suitable for high-pressure applications.

Castable three-dimensional stationary phase for electric field-driven applications

DOEpatents

Shepodd, Timothy J [Livermore, CA; Whinnery, Jr., Leroy; Even, Jr., William R.

2009-02-10

A polymer material useful as the porous dielectric medium for microfluidic devices generally and electrokinetic pumps in particular. The polymer material is produced from an inverse (water-in-oil) emulsion that creates a 3-dimensional network characterized by small pores and high internal volume, characteristics that are particularly desirable for the dielectric medium for electrokinetic pumps. Further, the material can be cast-to-shape inside a microchannel. The use of bifunctional monomers provides for charge density within the polymer structure sufficient to support electroosmotic flow. The 3-dimensional polymeric material can also be covalently bound to the channel walls thereby making it suitable for high-pressure applications.

Preparation of anionic polyurethane nanoparticles and blood compatible behaviors.

PubMed

Zhu, Qinshu; Wang, Yan; Zhou, Min; Mao, Chun; Huang, Xiaohua; Bao, Jianchun; Shen, Jian

2012-05-01

The anionic polyurethane nanoparticles (APU-NPs) were obtained by an emulsion polymerization method. It was found that the average size of the prepared APU-NPs is about 84 nm, and the APU-NPs have zeta-potential of -38.9 mV. The bulk characterization of synthesized APU-NPs was investigated by FTIR. The blood compatibility of APU-NPs was characterized by in vitro for coagulation tests, complement activation, platelet activation, cytotoxicity experiments, and hemolysis assay. The results showed that the APU-NPs synthesized in this paper are blood compatible with low level of cell cytotoxicity, and the results were significant for their potential use in vivo.

Biodegradable microparticles based on poly(D,L-lactide) as a protective transport system in ruminant digestion.

PubMed

Jay, Steven M; Peevy, Nolan J; Jenkins, Thomas C; Burg, Karen J L

2006-01-01

Despite its abundance in their diet, cattle are unable to directly digest cellulose. The bovine digestive tract overcomes this problem via the rumen, a portion of the stomach containing mixed anaerobic bacteria. These microbes, while breaking down foodstuffs, also perform undesirable processes such as biohydrogenation, in which unsaturated fatty acids become saturated, with deleterious cardiovascular effects. An approach to preventing this saturation entailing the use of polymeric microspheres to encapsulate feed supplements is proposed, with a single emulsion, solvent evaporation method used to formulate poly(D,L-lactide) microparticles for delivery of unsaturated fatty acids to ruminant abomasum.

Preparation, thermal property and morphology analysis of waterborne polyurethane-acrylate

NASA Astrophysics Data System (ADS)

Zhao, Zhenyu; Jing, Zefeng; Qiu, Fengxian; Dai, Yuting; Xu, Jicheng; Yu, Zongping; Yang, Pengfei

2017-01-01

A series of waterborne polyurethane-acrylate (WPUA) dispersions were prepared with isophorone diisocyanate (IPDI), polyether polyol (NJ-210), dimethylol propionic acid (DMPA), hydroxyethyl methyl acrylate (HEMA), different proportions of methyl methacrylate (MMA) and ethyl acrylate (MMA and EA) and initiating agent by the emulsion co-polymerization. The structures, thermal properties and morphology of WPUA films were characterized with FT-IR, DSC, SEM and AFM. Performances of the dispersions and films were studied by means of apparent viscidity, particle size and polydispersity, surface tension and mechanical properties. The obtained WPUA have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings and wood finishes.

Methods for Generating Hydrogel Particles for Protein Delivery

PubMed Central

Liu, Allen L.; García, Andrés J.

2016-01-01

Proteins represent a major class of therapeutic molecules with vast potential for the treatment of acute and chronic diseases and regenerative medicine applications. Hydrogels have long been investigated for their potential in carrying and delivering proteins. As compared to bulk hydrogels, hydrogel microparticles (microgels) hold promise in improving aspects of delivery owing to their less traumatic route of entry into the body and improved versatility. This review discusses common methods of fabricating microgels, including emulsion polymerization, microfluidic techniques, and lithographic techniques. Microgels synthesized from both natural and synthetic polymers are discussed, as are a series of microgels fashioned from environment-responsive materials. PMID:27160672

Surface Modification of Nanocellulose Substrates

NASA Astrophysics Data System (ADS)

Zoppe, Justin Orazio

Cellulose fibers constitute an important renewable raw material that is utilized in many commercial applications in non-food, paper, textiles and composite materials. Chemical functionalization is an important approach for improving the properties of cellulose based materials. Different approaches are used to graft polymeric chains onto cellulose substrates, which can be classified by two principal routes, namely 'grafting onto' or 'grafting from' methods. Never-dried cellulose nanocrystals (CNCs) or nanowhiskers produced from sulfuric acid hydrolysis of ramie fibers were used as substrates for surface chemical functionalization with various macromolecules. In addition, the use of cellulose nanocrystals to reinforce poly(epsilon-caprolactone) (PCL) nanofibers was studied. Chemical grafting with low molecular weight polycaprolactone diol onto cellulose nanocrystals was carried out in an attempt to improve the interfacial adhesion with the fiber matrix. Significant improvements in the mechanical properties of the nanofibers after reinforcement with unmodified cellulose nanocrystals were confirmed. Fiber webs from PCL reinforced with 2.5% unmodified CNCs showed ca. 1.5-fold increase in Young's modulus and ultimate strength compared to PCL webs. The CNCs were also grafted with poly(N-isopropylacrylamide) (poly(NiPAAm)) brushes via surface-initiated single-electron transfer living radical polymerization (SI-SETLRP) under various conditions at room temperature. The grafting process depended on the initiator and/or monomer concentrations used. No observable damage occurred to the CNCs after grafting, as determined by X-ray diffraction. Size exclusion chromatography analyses of polymer chains cleaved from the cellulose nanocrystals indicated that a higher degree of polymerization was achieved by increasing initiator or monomer loading, most likely caused by local heterogeneities yielding higher rates of polymerization. In addition, the colloidal stability and thermo-responsive behavior of poly(NiPAAm) brushes grafted from nanoparticles of CNCs of varying graft densities and molecular weights was investigated. Halo areas surrounding grafted CNCs that were adsorbed on silica and imaged with an AFM were indicative of the grafted polymer brushes. Aggregation of nanoparticles carrying grafts of high degree of polymerization was observed. The responsiveness of CNCs in liquid medium and as spin-coated films was determined by using light scattering, viscometry and Colloidal Probe Microscopy (CPM). Light transmittance measurements showed temperaturedependent aggregation originating from the different graft densities and molecular weights and a sharp increase in dispersion viscosity as the temperature approached the LCST. The lower critical solution temperature (LCST) of grafted poly(NiPAAm) brushes was found to decrease with the ionic strength as is the case of neat poly(NiPAAm) in aqueous solution. CPM in aqueous media for asymmetric systems consisting of thin films of CNCs and a colloidal silica probe showed the distinctive effects of the grafted polymer brushes on the interaction (repulsive and adhesive) forces. The origin of such forces was mainly electrostatic and steric in the case of bare and grafted CNCs, respectively. A decrease in the onset of attractive and adhesion forces of grafted CNCs films was observed with the ionic strength of the aqueous solution medium. The decreased mobility of polymer brushes upon partial collapse and decreased availability of hydrogen bonding sites with higher electrolyte concentration were hypothesized as main reasons for the less prominent polymer bridging between interacting surfaces. Finally, poly(NiPAAm)-g-CNCs were utilized as a Pickering emulsions stabilizer. All emulsions formed were oil-in-water confirmed by a drop test. Various drop sizes were obtained as characterized by laser scattering particle size analysis and optical microscopy. Anisotropic colloidal assemblies of grafted CNCs at the oil-water interface were observed in freeze-fractured samples via Transmission Electron Microscopy. Emulsions were stable for over three months at the time of writing this thesis, however rapidly broke above the LCST as determined by rheometry.

Quasi-Block Copolymers Based on a General Polymeric Chain Stopper.

PubMed

Sanguramath, Rajashekharayya A; Nealey, Paul F; Shenhar, Roy

2016-07-11

Quasi-block copolymers (q-BCPs) are block copolymers consisting of conventional and supramolecular blocks, in which the conventional block is end-terminated by a functionality that interacts with the supramolecular monomer (a "chain stopper" functionality). A new design of q-BCPs based on a general polymeric chain stopper, which consists of polystyrene end-terminated with a sulfonate group (PS-SO3 Li), is described. Through viscosity measurements and a detailed diffusion-ordered NMR spectroscopy study, it is shown that PS-SO3 Li can effectively cap two types of model supramolecular monomers to form q-BCPs in solution. Furthermore, differential scanning calorimetry data and structural characterization of thin films by scanning force microscopy suggests the existence of the q-BCP architecture in the melt. The new design considerably simplifies the synthesis of polymeric chain stoppers; thus promoting the utilization of q-BCPs as smart, nanostructured materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of sodium hypochlorite and peracetic acid on the surface roughness of acrylic resin polymerized by heated water for short and long cycles.

PubMed

Sczepanski, Felipe; Sczepanski, Claudia Roberta Brunnquell; Berger, Sandrine Bittencourt; Consani, Rafael Leonardo Xediek; Gonini-Júnior, Alcides; Guiraldo, Ricardo Danil

2014-10-01

To evaluate the surface roughness of acrylic resin submitted to chemical disinfection via 1% sodium hypochlorite (NaClO) or 1% peracetic acid (C2H4O3). The disc-shaped resin specimens (30 mm diameter ×4 mm height) were polymerized by heated water using two cycles (short cycle: 1 h at 74°C and 30 min at 100°C; conventional long cycle: 9 h at 74°C). The release of substances by these specimens in water solution was also quantified. Specimens were fabricated, divided into four groups (n = 10) depending on the polymerization time and disinfectant. After polishing, the specimens were stored in distilled deionized water. Specimens were immersed in 1% NaClO or 1% C2H4O3 for 30 min, and then were immersed in distilled deionized water for 20 min. The release of C2H4O3 and NaClO was measured via visual colorimetric analysis. Roughness was measured before and after disinfection. Roughness data were subjected to two-way ANOVA and Tukey's test. There was no interaction between polymerization time and disinfectant in influencing the average surface roughness (Ra, P = 0.957). Considering these factors independently, there were significant differences between short and conventional long cycles (P = 0.012), but no significant difference between the disinfectants hypochlorite and C2H4O3 (P = 0.366). Visual colorimetric analysis did not detect release of substances. It was concluded that there was the difference in surface roughness between short and conventional long cycles, and disinfection at acrylic resins polymerized by heated water using a short cycle modified the properties of roughness.

Effect of sodium hypochlorite and peracetic acid on the surface roughness of acrylic resin polymerized by heated water for short and long cycles

PubMed Central

Sczepanski, Felipe; Sczepanski, Claudia Roberta Brunnquell; Berger, Sandrine Bittencourt; Consani, Rafael Leonardo Xediek; Gonini-Júnior, Alcides; Guiraldo, Ricardo Danil

2014-01-01

Objective: To evaluate the surface roughness of acrylic resin submitted to chemical disinfection via 1% sodium hypochlorite (NaClO) or 1% peracetic acid (C2H4O3). Materials and Methods: The disc-shaped resin specimens (30 mm diameter ×4 mm height) were polymerized by heated water using two cycles (short cycle: 1 h at 74°C and 30 min at 100°C; conventional long cycle: 9 h at 74°C). The release of substances by these specimens in water solution was also quantified. Specimens were fabricated, divided into four groups (n = 10) depending on the polymerization time and disinfectant. After polishing, the specimens were stored in distilled deionized water. Specimens were immersed in 1% NaClO or 1% C2H4O3 for 30 min, and then were immersed in distilled deionized water for 20 min. The release of C2H4O3 and NaClO was measured via visual colorimetric analysis. Roughness was measured before and after disinfection. Roughness data were subjected to two-way ANOVA and Tukey's test. Results: There was no interaction between polymerization time and disinfectant in influencing the average surface roughness (Ra, P = 0.957). Considering these factors independently, there were significant differences between short and conventional long cycles (P = 0.012), but no significant difference between the disinfectants hypochlorite and C2H4O3 (P = 0.366). Visual colorimetric analysis did not detect release of substances. Conclusion: It was concluded that there was the difference in surface roughness between short and conventional long cycles, and disinfection at acrylic resins polymerized by heated water using a short cycle modified the properties of roughness. PMID:25512737

Color characteristics of low-chroma and high-translucence dental resin composites by different measuring modes.

PubMed

Lee, Y K; Lim, B S; Kim, C W; Powers, J M

2001-01-01

The objective of the described research was the evaluation of the effects of the differences in the color-measuring geometry (SCE, SCI) and the standard illuminant on the color and color change after polymerization and thermocycling of resin composites. White, translucent, and conventional shades of two brands of resin composites were measured before and after polymerization and after thermocycling according to the CIE L*a*b* color scale on a reflection spectrophotometer with SCE and SCI geometry under the standard illuminants A, D65, and C. Under both SCE and SCI modes, the color differences (DeltaE*) of specimens between the values measured under illuminants A and D65 or A and C were larger than those between D65 and C in unpolymerized, polymerized, and thermocycled conditions. With SCE geometry, DeltaE* after polymerization of the white shade group was 8.7-9.8 under D65, and was higher than the conventional shade group (p < 0.05) in both materials. With SCE geometry, DeltaE* between polymerized and thermocycled white, translucent shade was 4.4-7.1 under D65. With SCI geometry, the results were in general agreement with those of SCE mode. After polymerization, DeltaE* measured under illuminant A was generally higher than that under D65 or C (p < 0.01). After thermocycling, the color change was different depending on the color-measuring geometry and standard illuminant. Copyright 2001 John Wiley & Sons, Inc.

Fabrication of magnetic hydroxypropyl cellulose-g-poly(acrylic acid) porous spheres via Pickering high internal phase emulsion for removal of Cu(2+) and Cd(2.).

PubMed

Zhu, Yongfeng; Zheng, Yian; Zong, Li; Wang, Feng; Wang, Aiqin

2016-09-20

A series of magnetic hydroxypropyl cellulose-g-poly(acrylic acid) porous spheres were prepared via O/W Pickering high internal phase emulsions (HIPEs) integrated precipitation polymerization. The structure and composition of modified Fe3O4 and porous structures were characterized by TEM, XRD, TGA and SEM. The results indicated that the silanized Fe3O4 can influence greatly the pore structure of magnetic porous sphere in addition to non-negligible impacts of the proportion of mixed solvent and co-surfactant. The adsorption experiment demonstrated that the adsorption equilibrium can be reached within 40min and the maximal adsorption capacity was 300.00mg/g for Cd(2+) and 242.72mg/g for Cu(2+), suggesting its fast adsorption kinetics and high adsorption capacity. After five adsorption-desorption cycles, no significant changes in the adsorption capacity were observed, suggesting its excellent reusability. The magnetic porous sphere can be easily separated from the solution and then find its potential as a recyclable material for highly efficient removal of heavy metals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influences of MAA on the porous morphology of P(St-MAA) latex particles produced by batch soap-free emulsion polymerization followed by stepwise alkali/acid post-treatment.

PubMed

Deng, Wei; Li, Ronglong; Zhang, Mengjun; Gong, Lixiang; Kan, Chengyou

2010-09-01

Soap-free P(St-MAA) latex particles with variable styrene (St)/methacrylic acid (MAA) ratio were synthesized by batch emulsion copolymerization at 70 degrees C for 7h, and the particles with porous structure were obtained after stepwise alkali/acid post-treatment. The effects of MAA amount on the particle morphologies after the alkali and the stepwise alkali/acid post-treatments were investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Results indicated that the alkali-treated latex particles showed anomalous structure with rough surface, and no hollow was clearly identified inside them. When these alkali-treated particles were further treated with acid solution, the particle surface became much smoother, and porous morphology appeared. It was found that when the MAA amount was less than or equal to 4mol%, no obvious morphological variation was observed; while the latex particles showed clearly porous structure as the MAA amount increased to 6mol%; with the further increase of MAA amount to 8mol%, the pore size decreased distinctly. Copyright 2010 Elsevier Inc. All rights reserved.

Preparation and in vitro evaluation of heparin-loaded polymeric nanoparticles.

PubMed

Jiao, Y Y; Ubrich, N; Marchand-Arvier, M; Vigneron, C; Hoffman, M; Maincent, P

2001-01-01

Nanoparticles of a highly soluble macromolecular drug, heparin, were formulated with two biodegradable polymers (poly-E-caprolactone [PCL] and poly (D, L-lactic-co-glycolic-acid) 50/50 [PLAGA]) and two nonbiodegradable positively charged polymers (Eudragit RS and RL) by the double emulsion and solvent evaporation method, using a high-pressure homogenization device. The encapsulation efficiency and heparin release profiles were studied as a function of the type of polymers employed (alone or in combination) and the concentration of heparin. Optimal encapsulation efficiency was observed when 5000 IU of heparin were incorporated in the first emulsion. High drug entrapment efficiency was observed in both Eudragit RS and RL nanoparticles (60% and 98%, respectively), compared with PLAGA and PCL nanoparticles (<14%). The use of the two types of Eudragit in combination with PCL and PLAGA increased the encapsulation efficiency compared with these two biodegradable polymers used alone; however, the in vitro drug release was not modified and remained low. On the other hand, the addition of esterase to the dissolution medium resulted in a significant increase in heparin release. The in vitro biological activity of released heparin, evaluated by measuring the anti-Xa activity by a colorimetric assay, was conserved after the encapsulation process.

A new method for the preparation of polymeric porous layer open tubular columns for GC application

NASA Technical Reports Server (NTRS)

Shen, T. C.; Wang, M. L.

1995-01-01

A new method to prepare polymeric PLOT columns by using in situ polymerization technology is described. The method involves a straightforward in situ polymerization of the monomer. The polymer produced is directly coated on the metal tubing. This eliminates many of the steps needed in conventional polymeric PLOT column preparation. Our method is easy to operate and produces very reproducible columns, as shown previously (T. C. Shen. J. Chromatogr. Sci. 30, 239, 1992). The effects of solvents, tubing pretreatments, initiators and reaction temperatures in the preparation of PLOT columns are studied. Several columns have been developed to separate (1) highly polar compounds, such as water and ammonia or water and HCN, and (2) hydrocarbons and inert gases. A recent improvement has allowed us to produce bonded polymeric PLOT columns. These were studied, and the results are included also.

Oligonucleotides as probes for studying polymerization reactions in dilute aqueous solution

NASA Technical Reports Server (NTRS)

Kolb, V.; Orgel, L. E.; Miller, S. L. (Principal Investigator)

1994-01-01

We have prepared a [32P]-labled oligonucleotide probe carrying a free primary amine at its 3'-terminus. This probe is used to initiate polymerization of aziridine (ethyleneimine) in aqueous solution. The nature of the oligomeric products and the kinetics of their formation are then monitored by gel electrophoresis. Our results are generally consistent with those obtained using conventional techniques. We have also investigated the effect of polyanionic templates on the rate of oligomerization of aziridine. We find that water-soluble polyanions generally accelerate the polymerization. The sodium salt of polymethacrylic acid is the most effective of the templates that we studied. The methods introduced in this paper should be applicable to a variety of polymerization reactions in aqueous solution. They should greatly simplify the screening of potentially prebiotic polymerization reactions.

Nozzleless Fabrication of Oil-Core Biopolymeric Microcapsules by the Interfacial Gelation of Pickering Emulsion Templates.

PubMed

Leong, Jun-Yee; Tey, Beng-Ti; Tan, Chin-Ping; Chan, Eng-Seng

2015-08-05

Ionotropic gelation has been an attractive method for the fabrication of biopolymeric oil-core microcapsules due to its safe and mild processing conditions. However, the mandatory use of a nozzle system to form the microcapsules restricts the process scalability and the production of small microcapsules (<100 μm). We report, for the first time, a nozzleless and surfactant-free approach to fabricate oil-core biopolymeric microcapsules through ionotropic gelation at the interface of an O/W Pickering emulsion. This approach involves the self-assembly of calcium carbonate (CaCO3) nanoparticles at the interface of O/W emulsion droplets followed by the addition of a polyanionic biopolymer into the aqueous phase. Subsequently, CaCO3 nanoparticles are dissolved by pH reduction, thus liberating Ca(2+) ions to cross-link the surrounding polyanionic biopolymer to form a shell that encapsulates the oil droplet. We demonstrate the versatility of this method by fabricating microcapsules from different types of polyanionic biopolymers (i.e., alginate, pectin, and gellan gum) and water-immiscible liquid cores (i.e., palm olein, cyclohexane, dichloromethane, and toluene). In addition, small microcapsules with a mean size smaller than 100 μm can be produced by selecting the appropriate conventional emulsification methods available to prepare the Pickering emulsion. The simplicity and versatility of this method allows biopolymeric microcapsules to be fabricated with ease by ionotropic gelation for numerous applications.

Early reaction kinetics of contemporary glass-ionomer restorative materials.

PubMed

Roberts, Howard W; Berzins, David W

2015-02-01

To investigate polyalkenoate reaction rates in conventional glass-ionomer cement (GIC) and resin-modified glass ionomer (RMGI) restorative materials using infrared spectroscopy. Nine conventional GIC and six RMGI restorative materials were prepared according to manufacturer's directions and placed on a FTIR (Fourier transform infrared spectroscopy) diamond ATR (attenuated total reflectance) surface. FTIR spectra (700 to 1800 cm-1) were obtained each minute for 3 h. VLC specimens were light polymerized after 1 min; at 5 min, all samples were covered with gauze saturated with deionized water. Polyalkenoate reaction was determined by measuring area growth (Å/cm-1) between 1375 and 1500 cm-1. Mean peak areas were determined at 5, 15, 30, 90, and 180 min and compared using ANOVA (p = 0.05) RESULTS: For all RMGI materials, VLC polymerization inhibited the polyalkenoate reaction rate. Compared to conventional GIC, RMGI materials demonstrated less polyalkenoate reaction. Compared to dark curing, RMGI light polymerization significantly inhibited the polyalkenoate reaction rate. The addition of resin components to glass-ionomer products significantly retards and impedes the polyalkenoate reaction. The polyalkenoate reaction rate of RMGI products was significantly lower than that of self-curing GIC restorative materials. Furthermore, light activation of RMGI products further retards the polyalkenoate rate. When clinicians require the therapeutic benefit of a polyalkenoate product, perhaps a conventional GIC restorative product should be the first material of choice.

Modification of lignin for the production of new compounded materials.

PubMed

Hüttermann, A; Mai, C; Kharazipour, A

2001-05-01

The cell walls of woody plants are compounded materials made by in situ polymerization of a polyphenolic matrix (lignin) into a web of fibers (cellulose), a process that is catalysed by polyphenoloxidases (laccases) or peroxidases. The first attempt to transform the basic strategy of this natural process for use in human craftsmanship was the ancient lacquer method. The sap of the lacquer tree (Rhus verniciflua) contains large amounts of a phenol (urushiol), a polysaccharide and the enzyme laccase. This oil-in-water emulsion solidifies in the presence of oxygen. The Chinese began using this phenomenon for the production of highly creative artwork more than 6,000 years ago. It was the first example of an isolated enzyme being used as a catalyst to create an artificial plastic compound. In order to apply this process to the production of products on an industrial scale, an inexpensive phenol must be used, which is transferred by an enzyme to active radicals that react with different components to form a compounded material. At present, the following approaches have been studied: (1) In situ polymerization of lignin for the production of particle boards. Adhesive cure is based on the oxidative polymerization of lignin using phenoloxidases (laccase) as radical donors. This lignin-based bio-adhesive can be applied under conventional pressing conditions. The resulting particle boards meet German performance standards. By this process, 80% of the petrochemical binders in the wood-composite industry can be replaced by materials from renewable resources. (2) Enzymatic copolymerization of lignin and alkenes. In the presence of organic hydroperoxides, laccase catalyses the reaction between lignin and olefins. Detailed studies on the reaction between lignin and acrylate monomers showed that chemo-enzymatic copolymerization offers the possibility to produce defined lignin-acrylate copolymers. The system allows control of the molecular weights of the products in a way that has not been possible with chemical catalysts. This is a novel attempt to enzymatically induce grafting of polymeric side chains onto the lignin backbone, and it enables the utilization of lignin as part of new engineering materials. (3) Enzymatic activation of the middle-lamella lignin of wood fibers for the production of wood composites. The incubation of wood fibers with a phenol oxidizing enzyme results in oxidative activation of the lignin crust on the fiber surface. When such fibers are pressed together, boards are obtained which meet the German standards for medium-density fiber boards (MDF). The fibers are bound together in a way that comes close to that by which wood fibers are bound together in naturally grown wood. This process will, for the first time, yield wood composites that are produced solely from naturally grown products without any addition of resins.

Sustained-releasing hollow microparticles with dual-anticancer drugs elicit greater shrinkage of tumor spheroids.

PubMed

Baek, Jong-Suep; Choo, Chee Chong; Tan, Nguan Soon; Loo, Say Chye Joachim

2017-10-06

Polymeric particulate delivery systems are vastly explored for the delivery of chemotherapeutic agents. However, the preparation of polymeric particulate systems with the capability of providing sustained release of two or more drugs is still a challenge. Herein, poly (D, L-lactic-co-glycolic acid, 50:50) hollow microparticles co-loaded with doxorubicin and paclitaxel were developed through double-emulsion solvent evaporation technique. Hollow microparticles were formed through the addition of an osmolyte into the fabrication process. The benefits of hollow over solid microparticles were found to be higher encapsulation efficiency and a more rapid drug release rate. Further modification of the hollow microparticles was accomplished through the introduction of methyl-β-cyclodextrin. With this, a higher encapsulation efficiency of both drugs and an enhanced cumulative release were achieved. Spheroid study further demonstrated that the controlled release of the drugs from the methyl-β-cyclodextrin -loaded hollow microparticles exhibited enhanced tumor regressions of MCF-7 tumor spheroids. Such hollow dual-drug-loaded hollow microparticles with sustained releasing capabilities may have a potential for future applications in cancer therapy.

Light-responsive polymer microcapsules as delivery systems for natural active agents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bizzarro, Valentina; Carfagna, Cosimo; Cerruti, Pierfrancesco

2016-05-18

In this work we report the preparation and the release behavior of UV-responsive polymeric microcapsules containing essential oils as a core. The oil acted also as a monomer solvent during polymerization. Accordingly, the potentially toxic organic solvent traditionally used was replaced with a natural active substance, resulting in a more sustainable functional system. Polymer shell was based on a lightly cross-linked polyamide containing UV-sensitive azobenzene moieties in the main chain. The micro-sized capsules were obtained via interfacial polycondensation in o/w emulsion, and their mean size was measured via Dynamic Light Scattering. Shape and morphology were analyzed through Scanning Electron andmore » Optical Microscopy. UV-responsive behavior was evaluated via spectrofluorimetry, by assessing the release kinetics of a fluorescent probe molecule upon UV light irradiation (λ{sub max}=360 nm). The irradiated samples showed an increase in fluorescence intensity, in accordance with the increase of the probe molecule concentration in the release medium. As for the un-irradiated sample, no changes could be detected demonstrating the effectiveness of the obtained releasing system.« less

Waterborne Polyurethane Coatings with Covalently Linked Black Dye Sudan Black B

PubMed Central

Sun, Wei; Xu, Haiyan; Xu, Fei

2017-01-01

Colored waterborne polyurethanes have been widely used in paintings, leathers, textiles, and coatings. Here, a series of black waterborne polyurethanes (WPUs) with different ratios of black dye, Sudan Black B (SDB), were prepared by step-growth polymerization. WPU emulsions as obtained exhibit low particle sizes and remarkable storage stability at the same time. At different dye loadings, essential structural, statistical and thermal properties are characterized. FTIR (fourier transform infrared) spectra indicate that SDB is covalently linked into waterborne polyurethane chains. All of the WPUs with covalently linked SDB show better color fastness and resistance of thermal migration than those with SDB mixed physically. Besides, WPUs incorporated SDB covalently with different polymeric diols, polytetramethylene ether glycol (PTMG), polypropylene glycol (PPG), poly-1, 4-butylene adipate glycol (PBA) and polycaprolactone glycol (PCL), were prepared to obtain different properties to cater to a variety of practical demands. By a spraying method, the black WPUs can be directly used as metal coatings without complex dyeing process by simply mixing coating additive and other waterborne resins, which exhibit excellent coating performance. PMID:29143785

Preparation and encapsulation of white/yellow dual colored suspensions for electrophoretic displays

NASA Astrophysics Data System (ADS)

Han, Jingjing; Li, Xiaoxu; Feng, Yaqing; Zhang, Bao

2014-11-01

C.I. Pigment Yellow 181 (PY181) composite particles encapsulated by polyethylene (PE) were prepared by dispersion polymerization method, and C.I. Pigment Yellow 110 (PY110) composite particles encapsulated by polystyrene (PS) with mini-emulsion polymerization method were achieved, respectively. The modified pigments were characterized by fourier transform infrared spectroscopy, scanning electron microscope and transmission electron microscope. Compared with the PE-coated PY 181 pigments, the PS-coated PY-110 particles had a narrow particle size distribution, regular spherical and average particle size of 450 nm. Suspension 1 and suspension 3 were prepared by the two composite particles dispersed in isopar M. A chromatic electrophoretic display cell consisting of yellow particles was successfully fabricated using dispersions of yellow ink particles in a mixed dielectric solvent with white particles as contrast. The response behavior and the contrast ratio to the electric voltage were also examined. The contrast ratio of pigments modified by polystyrene was 1.48, as well as the response time was 2 s, which were better than those of pigments modified by polyethylene.

Influence of pH and temperature of dip-coating solution on the properties of cellulose acetate-ceramic composite membrane for ultrafiltration.

PubMed

Kaur, Harjot; Bulasara, Vijaya Kumar; Gupta, Raj Kumar

2018-09-01

Polymer-ceramic composite membranes were prepared by dip coating technique using 5 wt.% cellulose acetate (CA) solution at different temperatures (15 °C, 25 °C and 40 °C). The effect of pH (2-12) of the polymeric solution on the properties of the membranes was studied using SEM, EDAX, FTIR, gas and liquid permeation. The thickness of the polymeric layer depended on the interaction of CA solution with the surface of ceramic support. Membrane permeability decreased with increase in pH because of decrease in pore size and porosity resulting from strong interaction of the polymer layer with the ceramic support. The porosity and mean pore size of the prepared membranes were found to be 28-60% and 30-47 nm (ultrafiltration range), respectively. The optimized membrane (pH 7) was used for ultrafiltration of oil in water emulsions (100 and 200 mg/L). Oil rejection of 99.61% was obtained for 100 mg/L of oil concentration in water. Copyright © 2018 Elsevier Ltd. All rights reserved.

Preparation of crosslinked amphiphilic silver nanogel as thin film corrosion protective layer for steel.

PubMed

Atta, Ayman M; El-Mahdy, Gamal A; Al-Lohedan, Hamad A; Ezzat, Abdelrahman O

2014-07-17

Monodisperse silver nanoparticles were synthesized by a new developed method via reaction of AgNO3 and oleic acid with the addition of a trace amount of Fe3+ ions. Emulsion polymerization at room temperature was employed to prepare a core-shell silver nanoparticle with controllable particle size. N,N'-methylenebisacrylamide (MBA) and potassium peroxydisulfate (KPS) were used as a crosslinker, and as redox initiator system, respectively for crosslinking polymerization. The structure and morphology of the silver nanogels were characterized by Fourier transform infrared spectroscopy (FTIR), transmission and scanning electron microscopy (TEM and SEM). The effectiveness of the synthesized compounds as corrosion inhibitors for steel in 1 M HCl was investigated by various electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Monolayers of silver nanoparticle were self-assembled on the fresh active surface of the steel electrode and have been tested as a corrosion inhibitor for steel in 1 M HCl solution. The results of polarization measurements showed that nanogel particles act as a mixed type inhibitor.

Tunable Pickering Emulsions with Environmentally Responsive Hairy Silica Nanoparticles.

PubMed

Liu, Min; Chen, Xiaoli; Yang, Zongpeng; Xu, Zhou; Hong, Liangzhi; Ngai, To

2016-11-30

Surface modification of the nanoparticles using surface anchoring of amphiphilic polymers offers considerable scope for the design of a wide range of brush-coated hybrid nanoparticles with tunable surface wettability that may serve as new class of efficient Pickering emulsifiers. In the present study, we prepared mixed polymer brush-coated nanoparticles by grafting ABC miktoarm star terpolymers consisting of poly(ethylene glycol), polystyrene, and poly[(3-triisopropyloxysilyl)propyl methacrylate] (μ-PEG-b-PS-b-PIPSMA) on the surface of silica nanoparticles. The wettability of the as-prepared nanoparticles can be precisely tuned by a change of solvent or host-guest complexation. 1 H NMR result confirmed that such wettability change is due to the reorganization of the polymer chain at the grafted layer. We show that this behavior can be used for stabilization and switching between water-in-oil (W/O) and oil-in-water (O/W) emulsions. For hairy particles initially dispersed in oil, W/O emulsions were always obtained with collapsed PEG chains and mobile PS chains at the grafted layer. However, initially dispersing the hairy particles in water resulted in O/W emulsions with collapsed PS chains and mobile PEG chains. When a good solvent for both PS and PEG blocks such as toluene was used, W/O emulsions were always obtained no matter where the hairy particles were dispersed. The wettability of the mixed polymer brush-coated silica particles can also be tuned by host-guest complexation between PEG block and α-CD. More importantly, our result showed that surprisingly the resultant mixed brush-coated hairy nanoparticles can be employed for the one-step production of O/W/O multiple emulsions that are not attainable from conventional Pickering emulsifiers. The functionalized hairy silica nanoparticles at the oil-water interface can be further linked together utilizing poly(acrylic acid) as the reversible linker to form supramolecular colloidosomes, which show pH-dependent release of cargo.

Polymeric Materials for Aerospace Power and Propulsion: Overview of Polymer Research at NASA Glenn

NASA Technical Reports Server (NTRS)

Meador, Michael A.

2007-01-01

Weight, durability and performance are all major concerns for any NASA mission. Use of lightweight materials, such as fiber reinforced polymer matrix composites can lead to significant reductions in vehicle weight and improvements in vehicle performance. Research in the Polymeric Materials Branch at NASA Glenn is focused on improving the durability, properties, processability and performance of polymeric materials by utilizing both conventional polymer science and engineering as well as nanotechnology and bioinspired approaches. This presentation will provide an overview of these efforts and highlight recent progress.

Survey Study of Trunk Materials for Direct ATRP Grafting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saito, Tomonori; Chatterjee, Sabornie; Johnson, Joseph C.

2015-02-01

In previous study, we demonstrated a new method to prepare polymeric fiber adsorbents via a chemical-grafting method, namely atom-transfer radical polymerization (ATRP), and identified parameters affecting their uranium adsorption capacity. However, ATRP chemical grafting in the previous study still utilized conventional radiation-induced graft polymerization (RIGP) to introduce initiation sites on fibers. Therefore, the objective of the present study is to perform survey study of trunk fiber materials for direct ATRP chemical grafting method without RIGP for the preparation of fiber adsorbents for uranium recovery from seawater.

Formulation and evaluation of targeted nanoparticles for breast cancer theranostic system.

PubMed

Dadras, Pegah; Atyabi, Fatemeh; Irani, Shiva; Ma'mani, Leila; Foroumadi, Alireza; Mirzaie, Zahra Hadavand; Ebrahimi, Marzieh; Dinarvand, R

2017-01-15

Theranostic polymeric NPs developed for both cancer diagnosis and cancer therapy. This multifunctional polymeric vehicle was prepared by a single emulsion evaporation method, using carboxyl-terminated PLGA. LHRH as a targeting moiety, was conjugated to the surface of polymeric carrier by applying polyethylene glycol. The results indicated that the diameter of NPs was ~185.4±4.6nm as defined by DLS. The entrapment efficacy of docetaxel, silibinin, and SPIONs was 84.6±4.1%, 80.6±2.7%, and 77.9±4.3%, respectively. The NPs showed a triphasic in-vitro drug release pattern. MTT assay was done on two cell lines, MCF-7 and SKOV-3. Enhanced cellular uptake ability of the targeted NPs to MCF-7 was evaluated in-vitro by confocal laser scanning microscopy. The results indicated that compared to non-targeted NPs, the LHRH targeted NPs had significant efficacy at IC50 concentration. The effect of the NPs on VEGF expression in MCF-7 and SKOV-3 cells was investigated by Real-Time PCR method. VEGF mRNA level expression in MCF-7 cell line reduced by 83% in comparison to control cell line. The designed NPs can be used as promising multifunctional platform for detection and targeted drug delivery in breast cancer. Copyright © 2016 Elsevier B.V. All rights reserved.

Dye-attached magnetic poly(hydroxyethyl methacrylate) nanospheres for albumin depletion from human plasma.

PubMed

Gökay, Öznur; Karakoç, Veyis; Andaç, Müge; Türkmen, Deniz; Denizli, Adil

2015-02-01

The selective binding of albumin on dye-affinity nanospheres was combined with magnetic properties as an alternative approach for albumin depletion from human plasma. Magnetic poly(hydroxyethyl methacrylate) (mPHEMA) nanospheres were synthesized using mini-emulsion polymerization method in the presence of magnetite powder. The specific surface area of the mPHEMA nanospheres was found to be 1302 m(2)/g. Subsequent to Cibacron Blue F3GA (CB) immobilization onto mPHEMA nanospheres, a serial characterization processing was implemented. The quantity of immobilized CB was calculated as 800 μmol/g. Ultimately, albumin adsorption performance of the CB-attached mPHEMA nanospheres from both aqueous dissolving medium and human plasma were explored.

Design of polymeric immunomicrospheres for cell labelling and cell separation

NASA Technical Reports Server (NTRS)

Rembaum, A.; Margel, S.

1978-01-01

Synthesis of several classes of hydrophylic microspheres applied to cell labeling and cell separation is described. Five classes of cross-linked microspheres with functional groups such as carboxyl, hydroxyl, amide and/or pyridine groups were synthesized. These functional groups were used to bind covalently antibodies and other proteins to the surface of the microspheres. To optimize the derivatisation technique, polyglutaraldehyde immunomicrospheres were prepared and utilized. Specific populations of human and murine lymphocytes were labelled with microspheres synthesized by the emulsion of the ionizing radiation technique. The labelling of the cells by means of microspheres containing an iron core produced successful separation of B from T lymphocytes by means of a magnetic field.

Pharmacokinetics of intramuscular microparticle depot of valdecoxib in an experimental model.

PubMed

Agnihotri, Sagar M; Vavia, Pradeep R

2009-09-01

We did a prospective study to investigate pharmacokinetics of a single intramuscularly (i.m.) administered Valdecoxib (VC) polymeric microparticles in New Zealand white rabbits. Poly[lac(glc-leu)] microparticles encapsulating a potent cyclooxygenase-2- selective inhibitor, VC, were prepared by emulsion and solvent evaporation technique and administered i.m. to rabbits for pharmacokinetic study. A single i.m. dose of drug-loaded poly[lac(glc-leu)] microparticles resulted in sustained therapeutic drug levels in the plasma for 49 days. The relative bioavailability was increased severalfold as compared with unencapsulated drug. Injectable poly[lac(glc-leu)] microparticles hold promise for increasing drug bioavailability and reducing dosing frequency for better management of rheumatoid arthritis.

Mechanistic examination of pre-exfoliating confinement of surface-active polystyrene nanobeads within pristine clay.

PubMed

Khvan, Svetlana; Kim, Junkyung; Lee, Sang-Soo

2007-02-01

Hydrophobic polymer (PS) nanoparticles preformed through an emulsifier-free emulsion polymerization method were successfully incorporated into a gallery of pristine sodium montmorillonite via interfacial cation exchange. The polymer beads confined between clay nanosheets were capable of (1) preventing the silicate layers from restacking and (2) maintaining the exfoliated state of clay. The increase in the abundance of surface groups promoted adsorption of the nanobeads onto the silicate surface and eventually led to the establishment of strong polymer-clay interactions. These findings suggest that, on the basis of the obtained pre-exfoliated clay masterbatch, the presence of strong polymer-clay interactions could improve the mechanical performance of nanocomposites.

Chitosan-g-lactide copolymers for fabrication of 3D scaffolds for tissue engineering

NASA Astrophysics Data System (ADS)

Demina, T. S.; Zaytseva-Zotova, D. S.; Timashev, P. S.; Bagratashvili, V. N.; Bardakova, K. N.; Sevrin, Ch; Svidchenko, E. A.; Surin, N. M.; Markvicheva, E. A.; Grandfils, Ch; Akopova, T. A.

2015-07-01

Chitosan-g-oligo (L, D-lactide) copolymers were synthesized and assessed to fabricate a number of 3D scaffolds using a variety of technologies such as oil/water emulsion evaporation technique, freeze-drying and two-photon photopolymerization. Solid-state copolymerization method allowed us to graft up to 160 wt-% of oligolactide onto chitosan backbone via chitosan amino group acetylation with substitution degree reaching up to 0.41. Grafting of hydrophobic oligolactide side chains with polymerization degree up to 10 results in chitosan amphiphilic properties. The synthesized chitosan-g-lactide copolymers were used to design 3D scaffolds for tissue engineering such as spherical microparticles and macroporous hydrogels.

Probing of cosolvents in polymer latex materials by using solvatochromic fluorescence.

PubMed

Brouwer, Albert M; Raja, Tanzeela N; Biemans, Koen; Nabuurs, Tijs; Tennebroek, Ronald

2008-01-01

The process of film formation is of great importance for the application of organic coatings. In waterborne coatings, organic cosolvents are still indispensable, but regulations force the industry to reduce their amounts. Here we describe a method that uses the solvatochromic fluorescence of a probe molecule copolymerized in an emulsion polymerization process with different monomers to shed light on the partitioning of cosolvents in polymer latex materials. The formulation of the latex with organic cosolvents that are not very water soluble leads to a quantifiable redshift of the emission of the probe. The transfer of the cosolvent upon mixing of cosolvent-containing and cosolvent-free compartments can also be monitored.

Polymerization Kinetics: Monitoring Monomer Conversion Using an Internal Standard and the Key Role of Sample "t[subscript 0]"

ERIC Educational Resources Information Center

Colombani, Olivier; Langelier, Ophelie; Martwong, Ekkachai; Castignolles, Patrice

2011-01-01

The use of an internal standard is a conventional and convenient way to monitor the conversion of one or several monomers during a controlled radical polymerization. However, the validity of this technique relies on an accurate determination of the initial monomer-to-internal standard ratio, A[subscript 0], because all subsequent calculations of…

Chromatic changes to artificial irises produced using different techniques

NASA Astrophysics Data System (ADS)

Bannwart, Lisiane Cristina; Goiato, Marcelo Coelho; dos Santos, Daniela Micheline; Moreno, Amália; Pesqueira, Aldiéris Alves; Haddad, Marcela Filié; Andreotti, Agda Marobo; de Medeiros, Rodrigo Antonio

2013-05-01

Ocular prostheses are important determinants of their users' aesthetic recovery and self-esteem. Because of use, ocular prostheses longevity is strongly affected by instability of the iris color due to polymerization. The goal of this study is to examine how the color of the artificial iris button is affected by different techniques of artificial wear and by the application of varnish following polymerization of the colorless acrylic resin that covers the colored paint. We produce 60 samples (n=10) according to the wear technique applied: conventional technique without varnish (PE); conventional technique with varnish (PEV); technique involving a prefabricated cap without varnish (CA); technique involving a prefabricated cap with varnish (CAV); technique involving inverted painting without varnish (PI); and technique involving inverted painting with varnish (PIV). Color readings using a spectrophotometer are taken before and after polymerization. We submitted the data obtained to analyses of variance and Tukey's test (P<0.05). The color test shows significant changes after polymerization in all groups. The PE and PI techniques have clinically acceptable values of ΔE, independent of whether we apply varnish to protect the paint. The PI technique produces the least color change, whereas the PE and CA techniques significantly improve color stability.

Synthesis of silicone softener and its characteristics on cotton fabric.

PubMed

Robati, D

2007-02-15

This study was undertaken to examine the unresolved questions surrounding the influence of silicon softener on cotton fabrics. Results showed that the synthesized silicon softener was comparable with other tested conventional softener, According to present investigations the emulsions E1 and E2 is not economical and it is not evenly qualified and it become two phased after 24 h. But emulsion E3 was even and more economical. Moreover, it has high stability. In addition, measurement of kinetic and static friction show that the general effect of silicon softener on cotton cloth is the decrease of friction. Also, it was concluded that with increasing the add on percentage of softener, the crease of reflection angle did not change bending length and static and kinetic friction index significantly.

Development and characterization of polymeric nanoparticulate delivery system for hydrophillic drug: Gemcitabine

NASA Astrophysics Data System (ADS)

Khurana, Jatin

Gemcitabine is a nucleoside analogue, used in various carcinomas such as non small cell lung cancer, pancreatic cancer, ovarian cancer and breast cancer. The major setbacks to the conventional therapy with gemcitabine include its short half-life and highly hydrophilic nature. The objectives of this investigation were to develop and evaluate the physiochemical properties, drug loading and entrapment efficiency, in vitro release, cytotoxicity, and cellular uptake of polymeric nano-particulate formulations containing gemcitabine hydrochloride. The study also entailed development and validation of a high performance liquid chromatography (HPLC) method for the analysis of gemcitabine hydrochloride. A reverse phase HPLC method using a C18 Luna column was developed and validated. Alginate and Poly lactide co glycolide/Poly-epsilon-caprolactone (PLGA:PCL 80:20) nanoparticles were prepared by multiple emulsion-solvent evaporation methodology. An aqueous solution of low viscosity alginate containing gemcitabine was emulsified into 10% solution of dioctyl-sulfosuccinate in dichloro methane (DCM) by sonication. The primary emulsion was then emulsified in 0.5% (w/v) aqueous solution of polyvinyl alcohol (PVA). Calcium chloride solution (60% w/v) was used to cause cross linking of the polymer. For PLGA:PCL system, the polymer mix was dissolved in dichloromethane (DCM) and an aqueous gemcitabine (with and without sodium chloride) was emulsified under ultrasonic conditions (12-watts; 1-min). This primary emulsion was further emulsified in 2% (w/v) PVA under ultrasonic conditions (24-watts; 3-min) to prepare a multiple-emulsion (w/o/w). In both cases DCM, the organic solvent was evaporated (20- hours, magnetic-stirrer) prior to ultracentrifugation (10000-rpm for PLGA:PCL; 25000-rpm for alginate). The pellet obtained was washed thrice with de-ionized water to remove PVA and any free drug and re-centrifuged. The particles were re-suspended in de-ionized water and then lyophilized to obtain the dried powdered delivery formulation. Particle size and surface charge of the nano-particles were measured using zeta-sizer. The surface morphology and microstructure were evaluated by scanning electron microscopy The drug loading and entrapment efficiencies were evaluated by a HPLC method (Luna C18 column (4.6 X 250 mm), 95/5 (v/v) 0.04M ammonium acetate/acetonitrile mobile phase (pH 5.5), 1.0 ml/min flow rate and 268 nm UV detection). Differential scanning calorimetry (DSC) was used to determine the physical state of gemcitabine in the nanoparticles. The cytotoxicity in pancreatic cancer cells (BxPC-3) was evaluated by MTT assay. The cellular uptake of gemcitabine solution and gemcitabine loaded alginate nano-particle suspension in BxPC-3 cells was determined for 15, 30 and 60 minutes. The particle-size and surface-charge was 564.7+/-56.5nm and -25.65+/-1.94mV for PLGA:PCL and 210.6+/-6.90nm and -33.21+/-1.63mV for alginate. Both the nano-particles were distinctly spherical and non-porous. The drug load was 5.14% for PLGA:PCL and 6.87% for alginate-particles, and the practical entrapment efficiency was found to be 54.1 % and 22.4% respectively. However, in case of PLGA:PCL particles, a two-fold increase in the entrapment efficiency was observed with the addition of sodium-chloride. The absence of endothermic melting peak of the drug in the DSC thermogram was an indication of the non-crystalline state of gemcitabine in the nanoparticles. In addition, there was no cytotoxicity associated with nanoparticle concentrations at-or-below 5 mg/mL. The uptake of nano-particles was around 4 times higher than the solution with treatment for 15 minutes and increased to almost 7 times following treatment for 60 minutes. Gemcitabine hydrochloride could be successfully formulated into a sustained release nano-particulate formulation using calcium cross-linked alginate and dioctyl sulfo succinate system. The nano-particulate delivery system exhibited better cytotoxic activity and also significantly enhanced the accumulation of the drug in BxPC-3 cell monolayers.

Lipid nanoparticles based on butyl-methoxydibenzoylmethane: in vitro UVA blocking effect

NASA Astrophysics Data System (ADS)

Niculae, G.; Lacatusu, I.; Badea, N.; Meghea, A.

2012-08-01

The aim of the present study was to obtain efficient lipid nanoparticles loaded with butyl-methoxydibenzoylmethane (BMDBM) in order to develop cosmetic formulations with enhanced UVA blocking effect. For this purpose, two adequate liquid lipids (medium chain triglycerides and squalene) have been used in combination with two solid lipids (cetyl palmitate and glyceryl stearate) in order to create appropriate nanostructured carriers with a disordered lipid network able to accommodate up to 1.5% BMDBM. The lipid nanoparticles (LNs) were characterized in terms of particle size, zeta potential, entrapment efficiency, loading capacity and in vitro UVA blocking effect. The efficiency of lipid nanoparticles in developing some cosmetic formulations has been evaluated by determining the in vitro erythemal UVA protection factor. In order to quantify the photoprotective effect, some selected cream formulations based on BMDBM-LNs and a conventional emulsion were exposed to photochemical UV irradiation at a low energy to simulate the solar energy during the midday. The results obtained demonstrated the high ability of cream formulations based on BMDBM-LNs to absorb more than 96% of UVA radiation. Moreover, the developed cosmetic formulations manifest an enhanced UVA blocking effect, the erythemal UVA protection factor being four times higher than those specific to conventional emulsions.

Engineering of DNA polymerase I from Thermus thermophilus using compartmentalized self-replication.

PubMed

Aye, Seaim Lwin; Fujiwara, Kei; Ueki, Asuka; Doi, Nobuhide

2018-05-05

Although compartmentalized self-replication (CSR) and compartmentalized partnered replication (CPR) are powerful tools for directed evolution of proteins and gene circuits, limitations remain in the emulsion PCR process with the wild-type Taq DNA polymerase used so far, including long run times, low amounts of product, and false negative results due to inhibitors. In this study, we developed a high-efficiency mutant of DNA polymerase I from Thermus thermophilus HB27 (Tth pol) suited for CSR and CPR. We modified the wild-type Tth pol by (i) deletion of the N-terminal 5' to 3' exonuclease domain, (ii) fusion with the DNA-binding protein Sso7d, (iii) introduction of four known effective point mutations from other DNA polymerase mutants, and (iv) codon optimization to reduce the GC content. Consequently, we obtained a mutant that provides higher product yields than the conventional Taq pol without decreased fidelity. Next, we performed four rounds of CSR selection with a randomly mutated library of this modified Tth pol and obtained mutants that provide higher product yields in fewer cycles of emulsion PCR than the parent Tth pol as well as the conventional Taq pol. Copyright © 2018 Elsevier Inc. All rights reserved.

Biocompatible nanoemulsions based on hemp oil and less surfactants for oral delivery of baicalein with enhanced bioavailability

PubMed Central

Yin, Juntao; Xiang, Cuiyu; Wang, Peiqing; Yin, Yuyun; Hou, Yantao

2017-01-01

Baicalein (BCL) possesses high pharmacological activities but low solubility and stability in the intestinal tract. This study aimed to probe the potential of nanoemulsions (NEs) consisting of hemp oil and less surfactants in ameliorating the oral bioavailability of BCL. BCL-loaded NEs (BCL-NEs) were prepared by high-pressure homogenization technique to reduce the amount of surfactants. BCL-NEs were characterized by particle size, entrapment efficiency (EE), in vitro drug release, and morphology. Bioavailability was studied in Sprague-Dawley rats following oral administration of BCL suspensions, BCL conventional emulsions, and BCL-NEs. The obtained NEs were ~90 nm in particle size with an EE of 99.31%. BCL-NEs significantly enhanced the oral bioavailability of BCL, up to 524.7% and 242.1% relative to the suspensions and conventional emulsions, respectively. BCL-NEs exhibited excellent intestinal permeability and transcellular transport ability. The cytotoxicity of BCL-NEs was documented to be low and acceptable for oral purpose. Our findings suggest that such novel NEs and preparative process provide a promising alternative to current formulation technologies and suitable for oral delivery of drugs with bioavailability issues. PMID:28435268

Biocompatible nanoemulsions based on hemp oil and less surfactants for oral delivery of baicalein with enhanced bioavailability.

PubMed

Yin, Juntao; Xiang, Cuiyu; Wang, Peiqing; Yin, Yuyun; Hou, Yantao

2017-01-01

Baicalein (BCL) possesses high pharmacological activities but low solubility and stability in the intestinal tract. This study aimed to probe the potential of nanoemulsions (NEs) consisting of hemp oil and less surfactants in ameliorating the oral bioavailability of BCL. BCL-loaded NEs (BCL-NEs) were prepared by high-pressure homogenization technique to reduce the amount of surfactants. BCL-NEs were characterized by particle size, entrapment efficiency (EE), in vitro drug release, and morphology. Bioavailability was studied in Sprague-Dawley rats following oral administration of BCL suspensions, BCL conventional emulsions, and BCL-NEs. The obtained NEs were ~90 nm in particle size with an EE of 99.31%. BCL-NEs significantly enhanced the oral bioavailability of BCL, up to 524.7% and 242.1% relative to the suspensions and conventional emulsions, respectively. BCL-NEs exhibited excellent intestinal permeability and transcellular transport ability. The cytotoxicity of BCL-NEs was documented to be low and acceptable for oral purpose. Our findings suggest that such novel NEs and preparative process provide a promising alternative to current formulation technologies and suitable for oral delivery of drugs with bioavailability issues.

Amino Acid Bound Surfactants: A New Synthetic Family of Polymeric Monoliths Open Up Possibilities for Chiral Separations in Capillary Electrochromatography

PubMed Central

He, Jun; Wang, Xiaochun; Morrill, Mike; Shamsi, Shahab A.

2012-01-01

By combining a novel chiral amino-acid surfactant containing acryloyl amide tail, carbamate linker and leucine head group of different chain lengths with a conventional cross linker and a polymerization technique, a new “one-pot”, synthesis for the generation of amino-acid based polymeric monolith is realized. The method promises to open up the discovery of amino-acid based polymeric monolith for chiral separations in capillary electrochromatography (CEC). Possibility of enhanced chemoselectivity for simultaneous separation of ephedrine and pseudoephedrine containing multiple chiral centers, and the potential use of this amino-acid surfactant bound column for CEC and CEC coupled to mass spectrometric detection is demonstrated. PMID:22607448

Development of a water purifier for radioactive cesium removal from contaminated natural water by radiation-induced graft polymerization

NASA Astrophysics Data System (ADS)

Seko, Noriaki; Hoshina, Hiroyuki; Kasai, Noboru; Shibata, Takuya; Saiki, Seiichi; Ueki, Yuji

2018-02-01

Six years after the Fukushima-nuclear accident, the dissolved radioactive cesium (Cs) is now hardly detected in environmental natural waters. These natural waters are directly used as source of drinking and domestic waters in disaster-stricken areas in Fukushima. However, the possibility that some radioactive Cs adsorbed on soil or leaves will contaminate these natural waters during heavy rains or typhoon is always present. In order for the returning residents to live with peace of mind, it is important to demonstrate the safety of the domestic waters that they will use for their daily life. For this purpose, we have synthesized a material for selective removal of radioactive Cs by introducing ammonium 12-molybdophosphate (AMP) onto polyethylene nonwoven fabric through radiation-induced emulsion graft polymerization technique. Water purifiers filled with the grafted Cs adsorbent were installed in selected houses in Fukushima. The capability of the grafted adsorbent to remove Cs from domestic waters was evaluated for a whole year. The results showed that the tap water filtered through the developed water purifier contained no radioactive Cs, signifying the very effective adsorption performance of the developed grafted adsorbent. From several demonstrations, we have commercialized the water purifier named "KranCsair®". Furthermore, we have also developed a method for the mass production of the grafted nonwoven fabric. Using a 30 L grafting reactor, it was possible to produce the grafted nonwoven fabric with a suitable range of degree of grafting. When an irradiated roll of nonwoven trunk fabric with a length of 10 m and a width of 30 cm was set in the reactor filled with glycidyl methacrylate (GMA), AMP, Tween 80 monomer emulsion solution at 40 °C for 1 h, the difference of Dgs in the length and the width on roll of fabrics was negligible.

Preparation of a reversed-phase/anion-exchange mixed-mode spherical sorbent by Pickering emulsion polymerization for highly selective solid-phase extraction of acidic pharmaceuticals from wastewater.

PubMed

Huang, Chaonan; Li, Yun; Yang, Jiajia; Peng, Junyu; Jin, Jing; Dhanjai; Wang, Jincheng; Chen, Jiping

2017-10-27

The present work represents a simple and effective preparation of a novel mixed-mode anion-exchange (MAX) sorbent based on porous poly[2-(diethylamino)ethyl methacrylate-divinylbenzene] (poly(DEAEMA-DVB)) spherical particles synthesized by one-step Pickering emulsion polymerization. The poly(DEAEMA-DVB) particles were quaternized with 1,4-butanediol diglycidyl ether (BDDE) followed by triethylamine (TEA) via epoxy-amine reaction to offer strong anion exchange properties. The synthesized MAX sorbent was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, nitrogen adsorption-desorption measurements and elemental analysis. The MAX sorbent possessed regular spherical shape and narrow diameter distribution (15-35μm), a high IEC of 0.54meq/g, with carbon and nitrogen contents of 80.3% and 1.62%, respectively. Compared to poly(DEAEMA-DVB), the MAX sorbent exhibited decreased S BET (390.5 vs. 515.3m 2 g -1 ), pore volume (0.74 vs. 0.85cm 3 g -1 ) and pore size (16.8 vs. 17.3nm). Moreover, changes of N content for producing the MAX sorbent reveal a successful two-step quaternization, which can be highly related to such a high IEC. Finally, the MAX sorbent was successfully evaluated for selective isolation and purification of some selected acidic pharmaceuticals (ketoprofen, KEP; naproxen, NAP; and ibuprofen, IBP) from neutral (hydrocortisone, HYC), basic (carbamazepine, CAZ; amitriptyline, AMT) pharmaceuticals and other interferences in water samples using solid phase extraction (SPE). An efficient analytical method based on the MAX-based mixed-mode SPE coupled with HPLC-UV was developed for highly selective extraction and cleanup of acidic KEP, NAP and IBP in spiked wastewater samples. The developed method exhibited good sensitivity (0.009-0.085μgL -1 limit of detection), satisfactory recoveries (82.1%-105.5%) and repeatabilities (relative standard deviation < 7.9%, n=3). Copyright © 2017 Elsevier B.V. All rights reserved.

pH Sensitive Microcapsules for Delivery of Corrosion Inhibitors

NASA Technical Reports Server (NTRS)

Li, Wenyan; Calle, Luz M.

2006-01-01

A considerable number of corrosion problems can be solved by coatings. However, even the best protective coatings can fail by allowing the slow diffusion of oxygen and moisture to the metal surface. Corrosion accelerates when a coating delaminates. Often, the problems start when microscopic nicks or pits on the surface develop during manufacturing or through wear and tear. This problem can be solved by the incorporation of a self-healing function into the coating. Several new concepts are currently under development to incorporate this function into a coating. Conductive polymers, nanoparticles, and microcapsules are used to release corrosion-inhibiting ions at a defect site. The objective of this investigation is to develop a smart coating for the early detection and inhibition of corrosion. The dual function of this new smart coating system is performed by pH-triggered release microcapsules. The microcapsules can be used to deliver healing agents to terminate the corrosion process at its early stage or as corrosion indicators by releasing dyes at the localized corrosion sites. The dyes can be color dyes or fluorescent dyes, with or without pH sensitivity. Microcapsules were formed through the interfacial polymerization process. The average size of the microcapsules can be adjusted from 1 to 100 micron by adjusting the emulsion formula and the microcapsule forming conditions. A typical microcapsule size is around 10 microns with a narrow size distribution. The pH sensitivity of the microcapsule can also be controlled by adjusting the emulsion formula and the polymerization reaction time. Both corrosion indicator (pH indicator) and corrosion inhibitor containing microcapsules were formed and incorporated into paint systems. Test panels of selected steels and aluminum alloys were painted using these paints. Testing of compatibility between the microcapsule system and different paint systems are in progress. Initial experiments with the microcapsule containing paint show visible color changes at induced corrosion sites and improvement of corrosion protection. Further investigation of the performance of the coating using electrochemical techniques and long term exposure are currently underway.

Comparison of conventional and lipid emulsion formulations of amphotericin B: Pharmacokinetics and toxicokinetics in dogs.

PubMed

Nieto, J; Alvar, J; Rodríguez, C; San Andrés, M I; San Andrés, M D; González, F

2018-04-01

The major limiting factor in the use of amphotericin B (AmB) is cumulative nephrotoxicity. In previous studies, AmB mixed with Intralipid® 20% (AmB-IL), a parenteral fat emulsion, reduces its toxicity, increases its efficacy and is less expensive than other commercial amphotericin B lipid formulations. The pharmacokinetics and toxicity of the conventional deoxycholate AmB formulation (Fungizone®) and AmB-IL were compared in dogs. The pharmacokinetic of AmB was significantly modified and renal toxicity and infusion-related side effects were reduced when the drug was prepared in fat emulsion. In addition, pharmacokinetics and toxicity were evaluated after the administration of multiple doses of AmB-IL with the purpose of determining an optimal treatment protocol in dogs. When using a consecutive day administration regime, there was a significant drug accumulation together with an increase in creatinine values after each dose. However, when using three doses per week administration regime, similar maximum and minimum plasma concentrations were maintained. During the four weeks of treatment a moderate increase in the creatinine values was observed but none of the treatments were ended prematurely. All these data suggest that Intralipid®, similar to that seen previously in humans, favors AmB distribution to the organs, decreasing drug toxicity and increasing its therapeutic index in the dogs. The dose protocol evaluated (25mg/m 2 /48h/three times per week) produces maintenance of AmB plasma levels that were close to that obtained by others authors after administration of liposomal formulations of AmB and that have been demonstrated to be clinically effective. Copyright © 2018 Elsevier Ltd. All rights reserved.

Molecular engineering of side-chain liquid crystalline polymers by living cationic polymerization using Webster`s initiating system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Percec, V.

1993-12-31

Webster`s cationic initiating system (HO{sub 3}SCF{sub 3}/SMe{sub 2}) (Macromolecules, 23, 1918 (1990)) was shown by us (for a review see Adv. Mater., 4, 548 (1992)) to polymerize, via a living mechanism, mesogenic vinyl ethers which contain a large variety of functional groups. This is mostly because SMe{sub 2} is a softer nucleophile than any of the functional groups available in these monomers. The molecular engineering of side-chain liquid crystalline polymers with conventional and complex architectures via this polymerization technique will be discussed.

Evaluation of flexural strength and surface properties of prepolymerized CAD/CAM PMMA-based polymers used for digital 3D complete dentures.

PubMed

Arslan, Mustafa; Murat, Sema; Alp, Gulce; Zaimoglu, Ali

2018-01-01

The objectives of this in vitro study were to evaluate the flexural strength (FS), surface roughness (Ra), and hydrophobicity of polymethylmethacrylate (PMMA)-based computer-aided design/computer-aided manufacturing (CAD/CAM) polymers and to compare the properties of different CAD/CAM PMMA-based polymers with conventional heat-polymerized PMMA following thermal cycling. Twenty rectangular-shaped specimens (64 × 10 × 3.3 mm) were fabricated from three CAD/CAM PMMA-based polymers (M-PM Disc [M], AvaDent Puck Disc [A], and Pink CAD/CAM Disc Polident [P], and one conventional heat-polymerized PMMA (Promolux [C]), according to ISO 20795-1:2013 standards. The specimens were divided into two subgroups (n = 10), a control and a thermocycled group. The specimens in the thermocycled group were subjected to 5000 thermal cycling procedures (5 to 55°C; 30 s dwell times). The Ra value was measured using a profilometer. Contact angle (CA) was assessed using the sessile drop method to evaluate surface hydrophobicity. In addition, the FS of the specimens was tested in a universal testing machine at a crosshead speed of 1.0 mm/min. Surface texture of the materials was assessed using scanning electron microscope (SEM). The data were analyzed using two-way analysis of variance (ANOVA), followed by Tukey's HSD post-hoc test (α < 0.05). CAD/CAM PMMA-based polymers showed significantly higher FS than conventional heat-polymerized PMMA for each group (P < 0.001). CAD/CAM PMMA-based polymer [P] showed the highest FS, whereas conventional PMMA [C] showed the lowest FS before and after thermal cycling (P < 0.001). There were no significant differences among the Ra values of the tested denture base polymers in the control group (P > 0.05). In the thermocycled group, the lowest Ra value was observed for CAD/CAM PMMA-based polymer [M] (P < 0.001), whereas CAD/CAM PMMA-based polymers [A] and [P], and conventional PMMA [C] had similar Ra values (P > 0.05). Conventional PMMA [C] had a significantly lower CA and consequently lower hydrophobicity compared to the CAD/CAM polymers in the control group (P < 0.001). In the thermocycled group, CAD/CAM PMMA-based polymer [A] and conventional PMMA [C] had significantly higher CA, and consequently higher hydrophobicity when compared to CAD/CAM polymers [M] and [P] (P < 0.001). However, no significant differences were found among the other materials (P > 0.05). The FS and hydrophobicity of the CAD/CAM PMMA-based polymers were higher than the conventional heat-polymerized PMMA, whereas the CAD/CAM PMMA-based polymers had similar Ra values to the conventional PMMA. Thermocycling had a significant effect on FS and hydrophobicity except for the Ra of denture base materials.

Chemical projectile-target interaction and liquid immiscibility in impact glass from the Wabar craters, Saudi Arabia

NASA Astrophysics Data System (ADS)

Hamann, Christopher; Hecht, Lutz; Ebert, Matthias; Wirth, Richard

2013-11-01

Impact glasses are usually strongly affected by secondary alteration and chemical weathering. Thus, in order to understand relevant formation processes, detailed petrographic studies on unweathered impact glasses are necessary as preserved heterogeneities in quenched impact glasses may serve as a tool to better understand their genesis. Here, we report on petrography and microchemistry of impact glasses from the Wabar impact craters (Saudi Arabia) that, with an age of ∼300 years, are among the youngest terrestrial impact craters. The fact that parts of the IIIAB iron meteorite have survived impact and subsequent weathering is granting Wabar a special role among the presently 184 confirmed terrestrial impact structures. Electron microprobe analysis (EMPA) and transmission electron microscopy (TEM) obtained on the black impact melt/glass variety at Wabar suggest that meteoritic Fe was selectively mixed with high-silica target melt at high temperatures due to selective oxidation, resulting in high Fe/Ni ratios for the black melt (37 on average, individual values range from 13 to 449) and low Fe/Ni ratios for projectile droplets ("FeNi spheres" with a Fe/Ni ratio of 3 on average; Fe/Ni ratio for the meteorite is ∼12). The black melt shows emulsion textures that are the result of silicate liquid immiscibility. Liquid-liquid phase-separation resulted in the formation of a poorly polymerized, ultrabasic melt (Lfe) rich in divalent cations like Fe2+, Ca2+, or Mg2+, that is dispersed in a highly polymerized, high-silica melt (Lsi) matrix. The typical Wabar black melt emulsion displays a spheres-in-a-matrix texture of ∼10-20% Lfe homogeneously dispersed in the form of two sets of spheres and droplets (10-30 nm and 0.1-0.4 μm in diameter) in ∼80-90% Lsi matrix, plus occasionally disseminated FeNi spheres. Around large (>10 μm) FeNi spheres, however, the typical emulsion texture changes to ∼21% Lsi dispersed in ∼79% Lfe. This change of texture is interpreted as evidence for the transfer of meteoritic Fe from the meteoritic FeNi spheres into the target melt due to selective oxidation of Fe over Ni and Co. Variations in the bulk composition of Wabar black melt largely depend on the volume ratios between immiscible ultrabasic Lfe, felsic Lsi, and remains of meteoritic FeNi spheres. Based on natural occurrences of phase-separated glasses (this work and literature) and quenching experiments (literature), there is growing evidence that liquid immiscibility is a major process in the formation of glassy impactites.

Capreomycin oleate microparticles for intramuscular administration: Preparation, in vitro release and preliminary in vivo evaluation.

PubMed

Cambronero-Rojas, Adrián; Torres-Vergara, Pablo; Godoy, Ricardo; von Plessing, Carlos; Sepúlveda, Jacqueline; Gómez-Gaete, Carolina

2015-07-10

Capreomycin sulfate (CS) is a second-line drug used for the treatment of multidrug-resistant tuberculosis (MDR-TB). The adverse effects profile and uncomfortable administration scheme of CS has led to the development of formulations based on liposomes and polymeric microparticles. However, as CS is a water-soluble peptide that does not encapsulate properly into hydrophobic particulate matrices, it was necessary to reduce its aqueous solubility by forming the pharmacologically active capreomycin oleate (CO) ion pair. The aim of this research was to develop a new formulation of CO for intramuscular injection, based on biodegradable microparticles that encapsulate CO in order to provide a controlled release of the drug with reduced local and systemic adverse effects. The CO-loaded microparticles prepared by spray drying or solvent emulsion-evaporation were characterized in their morphology, encapsulation efficiency, in vitro/in vivo kinetics and tissue tolerance. Through scanning electron microscopy it was confirmed that the microparticles were monodisperse and spherical, with an optimal size for intramuscular administration. The interaction between CO and the components of the microparticle matrix was confirmed on both formulations by X-ray powder diffraction and differential scanning calorimetry analyses. The encapsulation efficiencies for the spray-dried and emulsion-evaporation microparticles were 92% and 56%, respectively. The in vitro kinetics performed on both formulations demonstrated a controlled and continuous release of CO from the microparticles, which was successfully reproduced on an in vivo rodent model. The results of the histological analysis demonstrated that none of the formulations produced significant tissue damage on the site of injection. Therefore, the results suggest that injectable CO microparticles obtained by spray drying and solvent emulsion-evaporation could represent an interesting therapeutic alternative for the treatment of MDR-TB. Copyright © 2015 Elsevier B.V. All rights reserved.

Achieving interconnected pore architecture in injectable PolyHIPEs for bone tissue engineering.

PubMed

Robinson, Jennifer L; Moglia, Robert S; Stuebben, Melissa C; McEnery, Madison A P; Cosgriff-Hernandez, Elizabeth

2014-03-01

Template polymerization of a high internal phase emulsion (polyHIPE) is a relatively new method to produce tunable high-porosity scaffolds for tissue regeneration. This study focuses on the development of biodegradable injectable polyHIPEs with interconnected porosity that have the potential to fill bone defects and enhance healing. Our laboratory previously fabricated biodegradable polyHIPEs that cure in situ upon injection; however, these scaffolds possessed a closed-pore morphology, which could limit bone ingrowth. To address this issue, HIPEs were fabricated with a radical initiator dissolved in the organic phase rather than the aqueous phase of the emulsion. Organic-phase initiation resulted in macromer densification forces that facilitated pore opening during cure. Compressive modulus and strength of the polyHIPEs were found to increase over 2 weeks to 43±12 MPa and 3±0.2 MPa, respectively, properties comparable to cancellous bone. The viscosity of the HIPE before cure (11.0±2.3 Pa·s) allowed for injection and filling of the bone defect, retention at the defect site during cure under water, and microscale integration of the graft with the bone. Precuring the materials before injection allowed for tuning of the work and set times. Furthermore, storage of the HIPEs before cure for 1 week at 4°C had a negligible effect on pore architecture after injection and cure. These findings indicate the potential of these emulsions to be stored at reduced temperatures and thawed in the surgical suite before injection. Overall, this work highlights the potential of interconnected propylene fumarate dimethacrylate polyHIPEs as injectable scaffolds for bone tissue engineering.

Preparation of PLGA/Rose Bengal colloidal particles by double emulsion and layer-by-layer for breast cancer treatment.

PubMed

Loya-Castro, María F; Sánchez-Mejía, Mariana; Sánchez-Ramírez, Dante R; Domínguez-Ríos, Rossina; Escareño, Noé; Oceguera-Basurto, Paola E; Figueroa-Ochoa, Édgar B; Quintero, Antonio; Del Toro-Arreola, Alicia; Topete, Antonio; Daneri-Navarro, Adrián

2018-05-15

The use of colloidal particles (CPs) in the transport of drugs is developing rapidly thanks to its effectiveness and biosafety, especially in the treatment of various types of cancer. In this study Rose Bengal/PLGA CPs synthesized by double emulsion (W/O/W) and by electrostatic adsorption (layer-by-layer), were characterized and evaluated as potential breast cancer treatment. CPs were evaluated in terms of size, zeta potential, drug release kinetics and cell viability inhibition efficacy with the triple negative breast cancer cell line HCC70. The results showed that both types of CPs can be an excellent alternative to conventional cancer treatment by taking advantage of the enhanced permeation and retention (EPR) effect, manifested by solid tumors; however, the double emulsion CPs showed more suitable delivery times of up to 60% within two days, while layer-by-layer showed fast release of 50% in 90 min. Both types of CPs were capable to decrease cell viability, which encourage us to further testing in in vivo models to prove their efficacy and feasible use in the treatment of triple negative breast cancer. Copyright © 2018 Elsevier Inc. All rights reserved.

Augmenting the antibiofilm efficacy of advanced noninvasive light activated disinfection with emulsified oxidizer and oxygen carrier.

PubMed

George, Saji; Kishen, Anil

2008-09-01

In this study, we tested the hypothesis that the inclusion of an oxidizer and oxygen carrier in the photosensitization formulation would facilitate comprehensive disinfection of matured endodontic biofilm by light-activated disinfection (LAD). Photosensitizing formulations containing methylene blue (MB) and an oxygen carrier alone (perfluorodecahydronaphthalene) (PF1) or in combination with oxidizer (H(2)O(2)) (PF2) or their emulsions formed with triton-X100 (Bio-Rad Laboratories, Hercules, CA) in different proportions (PF3 and PF4) were tested for photochemical properties and damage to the biofilm structure using confocal laser scanning microscopy. Conventional chemomechanical preparation, LAD using MB in water, and LAD using MB in emulsion (PF4) were also conducted on 10-week-old Enterococcus faecalis biofilm within root canals. MB in emulsion (PF4) was overall the most effective photosensitizer formulation for photooxidation, generation of singlet oxygen (p = 0.001), and in disinfecting biofilm bacteria. Advanced noninvasive LAD using a photosensitizer formulation containing oxidizer and oxygen carrier disrupted the biofilm matrix and facilitated comprehensive inactivation of biofilm bacteria. This modified photosensitizer formulation will have potential advantages in endodontic disinfection.

Production of Concentrated Pickering Emulsions with Narrow Size Distributions Using Stirred Cell Membrane Emulsification.

PubMed

Manga, Mohamed S; York, David W

2017-09-12

Stirred cell membrane emulsification (SCME) has been employed to prepare concentrated Pickering oil in water emulsions solely stabilized by fumed silica nanoparticles. The optimal conditions under which highly stable and low-polydispersity concentrated emulsions using the SCME approach are highlighted. Optimization of the oil flux rates and the paddle stirrer speeds are critical to achieving control over the droplet size and size distribution. Investigating the influence of oil volume fraction highlights the criticality of the initial particle loading in the continuous phase on the final droplet size and polydispersity. At a particle loading of 4 wt %, both the droplet size and polydispersity increase with increasing of the oil volume fraction above 50%. As more interfacial area is produced, the number of particles available in the continuous phase diminishes, and coincidently a reduction in the kinetics of particle adsorption to the interface resulting in larger polydisperse droplets occurs. Increasing the particle loading to 10 wt % leads to significant improvements in both size and polydispersity with oil volume fractions as high as 70% produced with coefficient of variation values as low as ∼30% compared to ∼75% using conventional homogenization techniques.

The unusual dynamics of parasite actin result from isodesmic polymerization

PubMed Central

Skillman, Kristen M.; Ma, Christopher I.; Fremont, Daved H.; Diraviyam, Karthikeyan; Cooper, John A.; Sept, David; Sibley, L. David

2013-01-01

Previous reports have indicated that parasite actins are short and inherently unstable, despite being required for motility. Here, we re-examine the polymerization properties of actin in Toxoplasma gondii (TgACTI), unexpectedly finding that it exhibits isodesmic polymerization in contrast to the conventional nucleation-elongation process of all previously studied actins from both eukaryotes and bacteria. TgACTI polymerization kinetics lacks both a lag phase and critical concentration, normally characteristic of actins. Unique among actins, the kinetics of assembly can be fit with a single set of rate constants for all subunit interactions, without need for separate nucleation and elongation rates. This isodesmic model accurately predicts the assembly, disassembly, and the size distribution of TgACTI filaments in vitro, providing a mechanistic explanation for actin dynamics in vivo. Our findings expand the repertoire of mechanisms by which actin polymerization is governed and offer clues about the evolution of self-assembling, stabilized protein polymers. PMID:23921463

Emulsification Of Eutectic Salt Mixtures In Fluid Vehicles

NASA Astrophysics Data System (ADS)

Vanderhoff, J. W.; El-Aasser, M. S.; Hawkins, T. W.

1988-05-01

High-internal-phase-volume emulsions of 75 volt 3/18/79 potassium iodide/sodium iodide/ urea model eutectic salt mixture in 83.5/16.5 Sartomer R-45HT hydroxy-terminated polybutadi-ene/Nujol mineral oil binder mixture were prepared at 60°C using water-in-oil emulsifiers and cured with isophorone diisocyanate or Desmodur N-100. The Nujol mineral oil enhanced the emulsification with a negligible reduction in the tensile properties of the cured elastomer. The average emulsion droplet sizes were ca. 200 nm initially, but increased slowly during curing to 500-1000 nm. The coalescence of the emulsion droplets followed the second-order dependence predicted by the von Smoluchowski diffusion-controlled flocculation; the rate constants were 1.05x10-18 and 9.58x10-18 cc/droplet-sec for dirnethyldioctadecylammonium bromide and Span 85 sorbitan trioleate, respectively. The isophorone diisocyanate reacted with emulsifiers containing primary hydroxyl or amine groups, to give unstable emulsions or no emulsions at all. Dimethyldioctadecylammonium bromide with no primary hydroxyl or amine groups, however, did not react with isocyanates and gave stable emulsions. The reaction of the R-45HT hydroxy-terminated polybutadiene with isophorone diisocyanate followed the expec-ted second-order kinetics with a rate constant of 3.42x10-4 liters/mole-sec at 60°C. The tensile properties of the cured elastomers and emulsions generally increased with increasing NCO/OH ratio up to 1.6/1.0. With increasing volume fraction of dispersed phase, the maximum stress (tensile strength) decreased, the maximum strain (percent elongation) increased, and the initial modulus (tensile modulus) decreased, in contrast to the behavior of conventional filled polymer systems; however, the maximum stresses were in accord with theoretical values for a filled polymer in which the filler particles bear no load, the initial moduli were in accord with the predictions of an isostrain model, and the maximum strain increased with in-creasing volume fraction of dispersed phase; these unusual variations, which were attributed to the liquid nature of the emulsion droplets, were used to estimate the elastomer proper-ties required to give the desired properties: 60-100 psi maximum stress, 80-150% maximum strain, and 500-2000 psi initial modulus for an 88/12 eutectic salt/crosslinked polybutadi-ene composite containing 20% aluminum particles. The addition of 20% aluminum particles gave a modest improvement in tensile properties, and the addition of 2.5% or 3.5% submicroscopic carbon black particles gave a greater improvement; however, the tensile properties were still slightly short of the desired properties.

Layered double hydroxide/polyethylene terephthalate nanocomposites. Influence of the intercalated LDH anion and the type of polymerization heating method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herrero, M.; Martinez-Gallegos, S.; Labajos, F.M.

2011-11-15

Conventional and microwave heating routes have been used to prepare PET-LDH (polyethylene terephthalate-layered double hydroxide) composites with 1-10 wt% LDH by in situ polymerization. To enhance the compatibility between PET and the LDH, terephthalate or dodecyl sulphate had been previously intercalated in the LDH. PXRD and TEM were used to detect the degree of dispersion of the filler and the type of the polymeric composites obtained, and FTIR spectroscopy confirmed that the polymerization process had taken place. The thermal stability of these composites, as studied by thermogravimetric analysis, was enhanced when the microwave heating method was applied. Dodecyl sulphate wasmore » more effective than terephthalate to exfoliate the samples, which only occurred for the terephthalate ones under microwave irradiation. - Graphical abstract: Conventional and microwave heating routes were used to prepare PET-LDH (polyethylene terephthalate-layered double hydroxide) composites with 1-10 wt% LDH by in situ polymerization. To enhance the compatibility between PET and the LDH, terephthalate or dodecyl sulphate was previously intercalated into the LDH. The microwave process improves the dispersion and the thermal stability of nanocomposites due to the interaction of the microwave radiation and the dipolar properties of EG and the homogeneous heating. Highlights: > LDH-PET compatibility is enhanced by preintercalation of organic anions. > Dodecylsulphate performance is much better than that of terephthalate. > Microwave heating improves the thermal stability of the composites. > Microwave heating improves as well the dispersion of the inorganic phase.« less

Development of a Supported Emulsion Liquid Membrane System for Propionic Acid Separation in a Microgravity Environment

NASA Technical Reports Server (NTRS)

Li, Jin; Hu, Shih-Yao B.; Wiencek, John M.

2001-01-01

Perstractive fermentation is a good way to increase the productivity of bioreactors. Using Propionibacteria as the model system, the feasibility of using supported emulsion liquid membrane (SELM) for perstractive fermentation is assessed in this study. Five industrial solvents were considered as the solvent for preparing the SELM. The more polar a solvent is, the higher the partition coefficient. However, toxicity of a solvent also increases with its polarity. CO-1055 (industrial decanol/octanol blend) has the highest partition coefficient toward propionic acid among the solvents that has no molecular toxicity toward Propionibacteria. A preliminary extraction study was conducted using tetradecane as solvent in a hydrophobic hollow fiber contactor. The result confirmed that SELM eliminates the equilibrium limitation of conventional liquid-liquid extraction, and allows the use of a non-toxic solvent with low partition coefficient.

The Rheology of a Three Component System: COAL/WATER/#4 Oil Emulsions.

NASA Astrophysics Data System (ADS)

Gilmartin, Barbara Jean

The purpose of this investigation was to study the rheology of a three component system, coal/water/#4 oil emulsions (COW), in which the third component, water, was present in a significant concentration, and to determine the applicability of existing theories from suspension rheology to the three component system studied. In a coal/water/oil emulsion, free coal particles adhere to the surface of the water droplets, preventing their coagulation, while the larger coal particles reside in the matrix of stabilized water droplets. The use of liquid fuels containing coal is a means of utilizing our nation's coal reserves while conserving oil. These fuels can be burned in conventional oil-fired furnaces. In this investigation, a high sulfur, high ash, bituminous coal was used, along with a heavy #4 oil to prepare the emulsions. The coal was ground to a log-normal distribution with an average particle size of 62 microns. A Haake RV3 concentric cylinder viscometer, with a ribbed measuring system, was used to determine the viscosity of the emulsions. A physical pendulum settling device measured the shift in center of mass of the COW as a function of time. The flow behavior of the fuel in pipes was also tested. In interpreting the data from the viscometer and the pipe flow experiments, a power law analysis was used in the region from 30 s('-1) to 200 s('-1). Extrapolation methods were used to obtain the low and high shear behavior of the emulsions. In the shear rate region found in boiler feed systems, COW are shear thinning with a flow behavior index of 0.7. The temperature dependent characteristic of the emulsions studied were similar and followed an Arrhenius type relationship. The viscosity of the COW decreases with increasing coal average particle size and is also a function of the width of the size distribution used. The type of coal used strongly influences the rheology of the fuel. The volatile content and the atomic oxygen to nitrogen ratio of the coal are the most predictive factors in terms of the variation in viscosity of the emulsion with coal type. The viscosity of the oil used is linearly related to the viscosity of the COW. The relative viscosity - concentration relationship for the emulsions was evaluated by an equation developed by Quemada for use in blood rheology: (eta)(,r) = (1 - (phi)/(phi)(,max))('-2). The best fit of the data to the equation was found when the coal plus water concentration was used for (phi). The maximum packing fraction increased with increasing shear rate, reflecting a breaking up of the agglomerates in the system. By using the relative packing fraction of the coal plus oil concentration, the relative viscosity of the emulsions tested at the three shear rates evaluted can be fit to the Quemada relative viscosity equation. In the pipe flow tests, the emulsions showed little time-dependent behavior, however they did exhibit a well effect. A fair correlation was obtained between pipe flow behavior and the results obtained in the viscometer. Coal/water/#4 oil emulsions behave as coal and water in oil systems and can be successfully modeled using theories from suspension rheology.

Nanophosphor composite scintillators comprising a polymer matrix

DOEpatents

Muenchausen, Ross Edward; Mckigney, Edward Allen; Gilbertson, Robert David

2010-11-16

An improved nanophosphor composite comprises surface modified nanophosphor particles in a solid matrix. The nanophosphor particle surface is modified with an organic ligand, or by covalently bonding a polymeric or polymeric precursor material. The surface modified nanophosphor particle is essentially charge neutral, thereby preventing agglomeration of the nanophosphor particles during formation of the composite material. The improved nanophosphor composite may be used in any conventional scintillator application, including in a radiation detector.

Temperature rise in ion-leachable cements during setting reaction.

PubMed

Kanchanavasita, W; Pearson, G J; Anstice, H M

1995-11-01

Resin-modified ion-leachable cements have been developed for use as aesthetic restorative materials. Their apparent improved physical and handling properties can make them more attractive for use than conventional glass-ionomers. However, they contain monomers which are known to contract on polymerization and produce a polymerization exotherm. This study evaluated the temperature rise during setting and the rate of dimensional change of several ion-leachable materials. The resin-modified ion-leachable cements demonstrated greater temperature rises and higher rates of contraction than conventional materials. Generally, the behaviour of these resin-modified materials was similar to that of composite resins. However, some resin-modified cements produced a temperature rise of up to 20 degrees C during polymerization which was greater than that of the composite resin. This temperature rise must be taken into account when using the materials in direct contact with dentine in deep cavities without pulp protection. Longer irradiation time than the recommended 20 s did not significantly increase the maximum temperature rise but slightly extended the time before the temperature started to decline. The temperature of the environment had a significant effect on the rate of dimensional change in some materials. The rate of polymerization contraction of light-activated cements was directly related to the observed temperature rise.

A thin porous substrate using bonded particles for reverse-emulsion electrophoretic displays

NASA Astrophysics Data System (ADS)

Ahumada, M.; Bryning, M.; Cromer, R.; Hartono, M.; Lee, S. J.

2012-03-01

A thin porous layer of bonded ceramic microparticles has been developed to provide structural integrity and a stationary matrix for use in reflective-mode reverse-emulsion electrophoretic displays (REED), based on self-assembled nanodroplets dispersed in a non-polar liquid. REED ink uses low-cost materials and manufacturing processes, yet is capable of video speed and low voltage operation below 10 V. Porous layers of titanium dioxide (TiO2) are prepared as thin as 10 microns by fluidizing the particles in a water-based slurry with polymeric adhesive. The slurry is distributed between glass shear plates, one of which serves as the substrate for the working device. Particle morphology is examined using scanning electron microscopy and layer uniformity is characterized by opacity measurements using a throughbeam fiber optic sensor. Performance of the bonded matrix with REED ink is compared to baseline performance of a paste mixture, comprised of the same ink and unbonded TiO2 particles. Results show that at 25% volume fraction, the bonded substrate improves image bistability and is better able to maintain both light and dark intensity after extensive switching. The same bonded substrate also improves image bistability when power is disconnected, even compared to a paste with 40% volume fraction of TiO2.

Synthesis and electrorheological characteristics of polyaniline/organoclay nanoparticles via Pickering emulsion polymerization

NASA Astrophysics Data System (ADS)

Fang, F. F.; Liu, Y. D.; Choi, H. J.

2010-12-01

Conducting polymer/inorganic composite particles have been regarded as a potential candidate material for electrorheological (ER) fluids when dispersed in non-conducting oils due to their synergistic physical properties such as enhanced thermal stability and high dielectric properties. In this study, we fabricated polyaniline (PANI)/clay nanoparticles with unique core-shell structure via Pickering emulsion in the phase of toluene by adopting exfoliated clay as a stabilizer. Successfully synthesized PANI nanospheres which were initialized by oil-soluble benzoyl peroxide possess a polydispersed size distribution of particles ranging from 200 nm to 1 µm. Surface morphology was revealed by SEM images in which some clay sheets were found to wrap the PANI nanoparticles compactly. TEM images explicitly confirm the position of exfoliated clay layers around the nanospheres. In addition, some nano-scaled particles showed an irregular shape because clay plates are difficult to bend while wrapping the very tiny PANI nanoparticles, so the x-ray diffraction (XRD) pattern did not indicate any obvious sharp peak, demonstrating the nearly completely exfoliated clay layers. Besides these, thermal gravimetric analysis (TGA) data also gave additional information on thermal stability and composition. Finally, the ER fluid was prepared by dispersing PANI/clay nanoparticles in silicone oil and the ER performance was investigated via a rotational rheometer under an applied electric field.

Field test of polymer modified asphalt concrete : Murphy Road to Lava Butte Section, The Dalles - California Highway, Deschutes County, Oregon : construction report.

DOT National Transportation Integrated Search

1990-12-01

This report covers the construction of open-graded asphalt concrete test sections using one conventional and three different polymerized binders. The binders were: 1) Chevron's conventional AC-20 as a control, 2) Elf Aquitane's Styrelf with SB polyme...

Fabrication of sub-micrometer-sized jingle bell-shaped hollow spheres from multilayered core-shell particles.

PubMed

Gu, Shunchao; Kondo, Tomohiro; Mine, Eiichi; Nagao, Daisuke; Kobayashi, Yoshio; Konno, Mikio

2004-11-01

Jingle bell-shaped hollow spheres were fabricated starting from multilayered particles composed of a silica core, a polystyrene inner shell, and a titania outer shell. Composite particles of silica core-polystyrene shell, synthesized by coating a 339-nm-sized silica core with a polystyrene shell of thickness 238 nm in emulsion polymerization, were used as core particles for a succeeding titania-coating. A sol-gel method was employed to form the titania outer shell with a thickness of 37 nm. The inner polystyrene shell in the multilayered particles was removed by immersing them in tetrahydrofuran. These successive procedures could produce jingle bell-shaped hollow spheres that contained a silica core in the titania shell.

Low-power upconversion in dye-doped polymer nanoparticles.

PubMed

Simon, Yoan C; Bai, Shuo; Sing, Michelle K; Dietsch, Hervé; Achermann, Marc; Weder, Christoph

2012-04-13

Examples of nanoscale low-power upconverting systems are rapidly increasing because of their potential application in numerous areas such as bioimaging or drug delivery. The fabrication of dye-doped cross-linked rubbery nanoparticles that exhibit upconversion even at relatively low power densities is reported here. The nanoparticles were prepared by surfactant-free emulsion polymerization of n-butylacrylate with divinylbenzene as a cross-linker, followed by dyeing of the resulting particles with a two-chromophore system composed of a palladium porphyrin sensitizer, and diphenylanthracene. Blue emission (≈440 nm) of these systems was observed upon excitation at 532 nm. In addition to their optical properties, the particles were characterized by electron microscopy and dynamic light scattering. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The impact of size on particulate vaccine adjuvants.

PubMed

Shah, Ruchi R; O'Hagan, Derek T; Amiji, Mansoor M; Brito, Luis A

2014-12-01

Particulate adjuvants have been successful at inducing increased immune responses against many poorly immunogenic antigens. However, the mechanism of action of these adjuvants often remains unclear. As more potential vaccine targets are emerging, it is becoming necessary to broaden our knowledge on the factors involved in generating potent immune responses to recombinant antigens with adjuvants. While composition of adjuvants is integral in defining the overall performance of an adjuvant, some physical parameters such as particle size, surface charge and surface modification may also contribute to the potency. In this review, we will try to highlight the role of particle size in controlling the immune responses to adjuvanted vaccines, with a focus on insoluble aluminum salts, oil-in-water emulsions, polymeric particles and liposomes.

Electrokinetic properties of polymer colloids

NASA Technical Reports Server (NTRS)

Micale, F. J.; Fuenmayor, D. Y.

1986-01-01

The surface of polymer colloids, especially polystyrene latexes, were modified for the purpose of controlling the electrokinetic properties of the resulting colloids. Achievement required a knowledge of electrical double layer charging mechanism, as a function of the electrolyte conditions, at the polymer/water interface. The experimental approach is to control the recipe formulation in the emulsion polymerization process so as to systematically vary the strong acid group concentration on the surface of the polymer particles. The electrophoretic mobility of these model particles will then be measured as a function of surface group concentration and as a function of electrolyte concentration and type. An effort was also made to evaluate the electrophoretic mobility of polystyrene latexes made in space and to compare the results with latexes made on the ground.

Symposium on Explosives and Pyrotechnics, 13th, Hilton Head Island, SC, Dec. 2-4, 1986, Proceedings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1987-01-01

The present conference on explosive and pyrotechnic technologies discusses the shock-sensitivity of RDX, the thermodynamic properties of RDX, TNT, nitroglycerine, and HMX energetic molecules, the dynamic resistivity of exploding conductors, the decomposition of azides, the critical shock-initiation energy of emulsion explosives, actuator valve optimization, pyrotechnic aerosolization from novel imbibed liquid matrices, tetrazole initiators, and polymeric binders for red phosphorus pellets. Also discussed are channel-effect studies, the dynamic desensitization of coal mine explosives, the electromagnetic and electrostatic protection of explosives, the reliability of fuze explosive trains, the hazardous properties of explosive chemicals, the emulsification of an explosive with a chemical foamingmore » agent, and low energy ignition of HMX using a foil bridge.« less

Synthesis and characterization of nanomagnetite particles and their polymer coated forms.

PubMed

Utkan, Guldem Guven; Sayar, Filiz; Batat, Pinar; Ide, Semra; Kriechbaum, Manfred; Pişkin, Erhan

2011-01-15

Superparamagnetic nanoparticles were prepared by coprecipitation of ferrous (Fe(2+)) and ferric (Fe(3+)) aqueous solution by a base. Nanomagnetite particles were coated with poly(St/PEG-EEM/DMAPM) and poly(St/PEG-MA/DMAPM) layer by emulsifier-free emulsion polymerization. Chemical structure of nanoparticles was characterized by both FTIR and (1)H NMR. Particle morphologies were determined by Zeta Sizer, DLS, XRD and SAXS. Structural analysis showed that after polymer coating nanomagnetite particles kept their superparamagnetic property. Besides the synthesized magnetites, polymer coated forms of these particles are more biocompatible, well dispersable and uniform. These properties make them a very strong candidate for bioengineering applications, such as bioseparation, gene transfer. Copyright © 2010 Elsevier Inc. All rights reserved.

Ca (OH)2Nanoparticles Based on Acrylic Copolymers for the consolidation and protection of Ancient Egypt Calcareous Stone Monuments

NASA Astrophysics Data System (ADS)

Al-Dosari, Mohammad A.; Darwish, Sawsan S.; Adam, Mahmoud A.; Elmarzugi, Nagib A.; Al-Mouallimi, Nadia; Ahmed, Sayed M.

2017-04-01

The deterioration of calcareous stones materials used in artistic/architectural field is one of the most serious problems facing conservation today. The aim of this study was to evaluate the effectiveness of nanosized particles of calcium hydroxide (slaked lime) as a consolidation and protection material dispersed in acrylic copolymer, poly ethylmethacrylate/methylacrylate (70:30) (Poly (EMA/MA), for calcareous stone monuments and painted surfaces affected by different kinds of decay. The synthesis process of Ca (OH)2 nanoparticles/polymer nanocomposites have been prepared by in situ emulsion polymerization system. The prepared nanocomposite containing 5% of Ca (OH)2 nanoparticles showed obvious transparency features and represent nanocomposites coating technology with hydrophobic, consolidating and well protection properties.

Molecularly Imprinted Polymers: Novel Discovery for Drug Delivery.

PubMed

Dhanashree, Surve; Priyanka, Mohite; Manisha, Karpe; Vilasrao, Kadam

2016-01-01

Molecularly imprinted polymers (MIP) are novel carriers synthesized by imprinting of a template over a polymer. This paper presents the recent application of MIP for diagnostic and therapeutic drug delivery. MIP owing to their 3D polymeric structures and due to bond formation with the template serves as a reservoir of active causing stimuli sensitive, enantioselective, targetted and/or controlled release. The review elaborates about key factors for optimization of MIP, controlled release by MIP for various administration routes various forms like patches, contact lenses, nanowires along with illustrations. To overcome the limitation of organic solvent usage causing increased cost, water compatible MIP and use of supercritical fluid technology for molecular imprinting were developed. Novel methods for developing water compatible MIP like pickering emulsion polymerization, co-precipitation method, cyclodextrin imprinting, surface grafting, controlled/living radical chain polymerization methods are described with illustration in this review. Various protein imprinting methods like bulk, epitope and surface imprinting are described along with illustrations. Further, application of MIP in microdevices as biomimetic sensing element for personalized therapy is elaborated. Although development and application of MIP in drug delivery is still at its infancy, constant efforts of researchers will lead to a novel intelligent drug delivery with commercial value. Efforts should be directed in developing solid oral dosage forms consisting of MIP for therapeutic protein and peptide delivery and targeted release of potent drugs addressing life threatening disease like cancer. Amalgamation of bio-engineering and pharmaceutical techniques can make these future prospects into reality.

Naltrexone-loaded poly[La-(Glc-Leu)] polymeric microspheres for the treatment of alcohol dependence: in vitro characterization and in vivo biocompatibility assessment.

PubMed

Pagar, Kunal P; Vavia, Pradeep R

2014-06-01

The poly[La-(Glc-Leu)] copolymer was applied in the present investigation as polymeric carrier to fabricate naltrexone (NTX)-loaded poly[La-(Glc-Leu)] microspheres in the single emulsion solvent evaporation technique for the long-term treatment of alcohol dependence. Newly synthesized poly[La-(Glc-Leu)] copolymer exhibited diminished crystallanity, good biocompatibility and favorable biodegradability to be explored for drug delivery application. Scanning Electron Microscopy study revealed smooth and spherical-shaped NTX-loaded polymeric microspheres with a mean size of 10-90 µm. Influence of various decisive formulation variables such as amount of polymer, stabilizer concentration, homogenization speed, homogenization time, drug loading and organic-to-aqueous phase ratio on particle size, and entrapment efficiency was studied. Differential scanning calorimeter and X-ray diffractometry study confirmed the drug entrapment within polymer matrix into the microsphere environment. In vitro drug release showed the sustained drug release of formulation for the period of 28 d giving biphasic release pattern. Histological examination of NTX-loaded poly[La-(Glc-Leu)] microspheres injected intramuscularly into the thigh muscle of Wistar rats showed minimal inflammatory reaction, demonstrating that NTX-loaded microspheres were biocompatible. Insignificant increase in the serum creatine phosphokinase level (p < 0.05) as compared with the normal value revealed good muscle compatibility of the poly[La-(Glc-Leu)] microsphere system. Biocompatible nature and sustained drug-release action of poly[La-(Glc-Leu)] microspheres may have potential application in depot therapy.

Oxidative Reactions with Nonaqueous Enzymes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jonathan S. Dordick; Douglas Clark; Brian H Davison

2001-12-30

The objective of this work is to demonstrate a proof-of-concept of enzymatic oxidative processing in nonaqueous media using alkene epoxidation and phenolic polymerization as relevant targets. This project will provide both the fundamental and applied investigations necessary to initiate the implementation of oxidative biocatalysts as commercially relevant alternatives to chemical processing in general, and to phenolic polymerizations and alkene epoxidation specifically. Thus, this work will address the Bioprocessing Solicitation Area to: (1) makes major improvements to phenolic polymerization and alkene epoxidation technologies; (2) is expected to be cost competitive with competing conventional processes; and (3) produces higher yields with lessmore » waste.« less

Porosity, water sorption and solubility of denture base acrylic resins polymerized conventionally or in microwave.

PubMed

Figuerôa, Rosana Marques Silva; Conterno, Bruna; Arrais, César Augusto Galvão; Sugio, Carolina Yoshi Campos; Urban, Vanessa Migliorini; Neppelenbroek, Karin Hermana

2018-01-01

The proper selection of polymerization cycle is important to prevent overheating of the monomer that could cause degradation, porosity and, consequently, deleterious effects on the denture base properties. Objective This study evaluated the porosity, water sorption and solubility of acrylic resins (Vipi Cril-VC and Vipi Wave-VW) after conventional or microwave polymerization cycles. Material and Methods Specimens (n = 10) were made and cured: 1-WB = 65°C during 90 min + boiling during 90 min (VC cycle - control group); 2-M25 = 10 min at 270 W + 5 min at 0 W + 10 min at 360 W (VW cycle); 3-M3 = 3 min at 550 W; and 4-M5 = 5 min at 650 W. Afterward, they were polished and dried in a dessicator until a constant mass was reached. Specimens were then immersed in distilled water at 37°C and weighed regularly until a constant mass was achieved. For porosity, an additional weight was made with the specimen immediately immersed in distilled water. For water sorption and solubility, the specimens were dried again until equilibrium was reached. Data were submitted to 2 way-ANOVA and Tukey HSD (α=0.05). Results Porosity mean values below 1.52% with no significant difference among groups for both materials were observed. Resins showed water sorption and solubility values without a significant difference. However, there was a significant difference among groups for these both properties (P<0.013). The highest sorption (2.43%) and solubility (0.13%) values were obtained for WB and M3, respectively. Conclusions The conventional acrylic resin could be polymerized in a microwave since both the materials showed similar performance in the evaluated properties. Shorter microwave cycles could be used for both the materials without any detectable increase in volume porosity.

Synthesis and characterization of fluorinated polyacrylate latex emulsified with novel surfactants.

PubMed

Zhang, Cuifeng; Xu, Tingting; Bao, Zhongbin; Chen, Lijun

2017-01-01

The fluorinated polyacrylate latex were successfully prepared with semi- continuous seeded emulsion polymerization of butyl acrylate (BA), methyl methacrylate (MMA) and hexafluorobutyl methacrylate (HFMA) which was initiated with potassium persulfate (KPS) initiator and emulsified with the novel mixed surfactants of sodium lauryl glutamate (SLG) and alkylphenol ethoxylates (OP-10). The structure of the resultant latex was confirmed by Fourier transform infrared spectroscopy (FTIR). The particle size of the latex was measured by Zetatrac dynamic light scattering detector. The film of latex was tested by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and contact angle (CA). The optimum conditions of preparing the novel fluorinated polyacrylate latex are optimized and the results are as follows: the amount of emulsifiers is 4.0%; mass ratio of SLG to OP-10 is 1:1, the amount of the initiator is 0.6%. The mass ratio of MMA to BA is 1:1 and the amount of HFMA is 7.0%. In this case, the conversion is high and the polymerization stability is good. In addition, the water resistance and thermal properties of the latex films were improved significantly in comparison with the film of the latex prepared without the fluorinated monomer.

Hybrid self-healing matrix using core-shell nanofibers and capsuleless microdroplets.

PubMed

Lee, Min Wook; An, Seongpil; Lee, Changmin; Liou, Minho; Yarin, Alexander L; Yoon, Sam S

2014-07-09

In this work, we developed novel self-healing anticorrosive hierarchical coatings that consist of several components. Namely, as a skeleton we prepared a core-shell nanofiber mat electrospun from emulsions of cure material (dimethyl methylhydrogen siloxane) in a poly(acrylonitrile) (PAN) solution in dimethylformamide. In these nanofibers, cure is in the core, while PAN is in the shell. The skeleton deposited on a protected surface is encased in an epoxy-based matrix, which contains emulsified liquid droplets of dimethylvinyl-terminated dimethylsiloxane resin monomer. When such hierarchical coatings are damaged, cure is released from the nanofiber cores and the resin monomer, released from the damaged matrix, is polymerized in the presence of cure. This polymerization and solidification process takes about 1-2 days and eventually heals the damaged material when solid poly(dimethylsiloxane) resin is formed. The self-healing effect was demonstrated using an electrochemical analogue of the scanning vibrating electrode technique. Damaged samples were left for 2 days. After that, the electric current through a damaged coating was found to be negligibly small for the samples with self-healing properties. On the other hand, for the samples without self-healing properties, the electric current was significant.

Synthesis and characterization of fluorinated polyacrylate latex emulsified with novel surfactants

PubMed Central

Zhang, Cuifeng; Xu, Tingting; Bao, Zhongbin; Chen, Lijun

2017-01-01

Abstract The fluorinated polyacrylate latex were successfully prepared with semi- continuous seeded emulsion polymerization of butyl acrylate (BA), methyl methacrylate (MMA) and hexafluorobutyl methacrylate (HFMA) which was initiated with potassium persulfate (KPS) initiator and emulsified with the novel mixed surfactants of sodium lauryl glutamate (SLG) and alkylphenol ethoxylates (OP-10). The structure of the resultant latex was confirmed by Fourier transform infrared spectroscopy (FTIR). The particle size of the latex was measured by Zetatrac dynamic light scattering detector. The film of latex was tested by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and contact angle (CA). The optimum conditions of preparing the novel fluorinated polyacrylate latex are optimized and the results are as follows: the amount of emulsifiers is 4.0%; mass ratio of SLG to OP-10 is 1:1, the amount of the initiator is 0.6%. The mass ratio of MMA to BA is 1:1 and the amount of HFMA is 7.0%. In this case, the conversion is high and the polymerization stability is good. In addition, the water resistance and thermal properties of the latex films were improved significantly in comparison with the film of the latex prepared without the fluorinated monomer. PMID:29491785

Evaluation of the White Test for the Intraoperative Detection of Bile Leakage

PubMed Central

Leelawat, Kawin; Chaiyabutr, Kittipong; Subwongcharoen, Somboon; Treepongkaruna, Sa-ad

2012-01-01

We assess whether the White test is better than the conventional bile leakage test for the intraoperative detection of bile leakage in hepatectomized patients. This study included 30 patients who received elective liver resection. Both the conventional bile leakage test (injecting an isotonic sodium chloride solution through the cystic duct) and the White test (injecting a fat emulsion solution through the cystic duct) were carried out in the same patients. The detection of bile leakage was compared between the conventional method and the White test. A bile leak was demonstrated in 8 patients (26.7%) by the conventional method and in 19 patients (63.3%) by the White test. In addition, the White test detected a significantly higher number of bile leakage sites compared with the conventional method (Wilcoxon signed-rank test; P < 0.001). The White test is better than the conventional test for the intraoperative detection of bile leakage. Based on our study, we recommend that surgeons investigating bile leakage sites during liver resections should use the White test instead of the conventional bile leakage test. PMID:22547901

Evaluation of the white test for the intraoperative detection of bile leakage.

PubMed

Leelawat, Kawin; Chaiyabutr, Kittipong; Subwongcharoen, Somboon; Treepongkaruna, Sa-Ad

2012-01-01

We assess whether the White test is better than the conventional bile leakage test for the intraoperative detection of bile leakage in hepatectomized patients. This study included 30 patients who received elective liver resection. Both the conventional bile leakage test (injecting an isotonic sodium chloride solution through the cystic duct) and the White test (injecting a fat emulsion solution through the cystic duct) were carried out in the same patients. The detection of bile leakage was compared between the conventional method and the White test. A bile leak was demonstrated in 8 patients (26.7%) by the conventional method and in 19 patients (63.3%) by the White test. In addition, the White test detected a significantly higher number of bile leakage sites compared with the conventional method (Wilcoxon signed-rank test; P < 0.001). The White test is better than the conventional test for the intraoperative detection of bile leakage. Based on our study, we recommend that surgeons investigating bile leakage sites during liver resections should use the White test instead of the conventional bile leakage test.

Sieving polymer synthesis by reversible addition fragmentation chain transfer polymerization.

PubMed

Nai, Yi Heng; Jones, Roderick C; Breadmore, Michael C

2013-12-01

Replaceable sieving polymers are the fundamental component for high resolution nucleic acids separation in CE. The choice of polymer and its physical properties play significant roles in influencing separation performance. Recently, reversible addition fragmentation chain transfer (RAFT) polymerization has been shown to be a versatile polymerization technique capable of yielding well defined polymers previously unattainable by conventional free radical polymerization. In this study, a high molecular weight PDMA at 765 000 gmol-1 with a PDI of 1.55 was successfully synthesized with the use of chain transfer agent - 2-propionic acidyl butyl trithiocarbonate (PABTC) in a multi-step sequential RAFT polymerization approach. This study represents the first demonstration of RAFT polymerization for synthesizing polymers with the molecular weight range suitable for high resolution DNA separation in sieving electrophoresis. Adjustment of pH in the reaction was found to be crucial for the successful RAFT polymerization of high molecular weight polymer as the buffered condition minimizes the effect of hydrolysis and aminolysis commonly associated with trithiocarbonate chain transfer agents. The separation efficiency of PABTC-PDMA was found to have marginally superior separation performance compared to a commercial PDMA formulation, POP™-CAP, of similar molecular weight range.

Effect of heat polymerization conditions and microwave on the flexural strength of polymethyl methacrylate

PubMed Central

Ozkir, Serhat Emre; Yilmaz, Burak; Unal, Server Mutluay; Culhaoglu, Ahmet; Kurkcuoglu, Isin

2018-01-01

Objective: The objective of this study is the effect of different heat polymerization conditions on the strength of polymethyl methacrylate (PMMA) resin base is unknown. Distinguishing one method that provides improved mechanical properties may be beneficial to the clinical success of complete and partial dentures and overdentures. The purpose of this study was to evaluate the effect of different polymerization methods on the flexural strength of a dental PMMA resin. Materials and Methods: Forty PMMA specimens (64 mm × 10 mm × 4 mm) were prepared with 4 different polymerization methods (n = 10); heat polymerization at 74°C for 9 h, at 100°C for 40 min, and with 620 kPa pressure at 100°C for 20 min. The remaining group of specimens was microwave polymerized at 180 W for 6 min. All specimens were thermocycled at 5°C and 55°C for 5000 times. Three-point flexure test was used to measure the flexural strength of specimens. One-way ANOVA and Tukey Honestly Significant Difference were applied to analyze the differences in flexural strengths (α = 0.05). Results: The flexural strength of heat-polymerized groups was similar. The flexural strength of microwave polymerized group was significantly different and lower than the other groups (P < 0.05). Conclusion: Polymerizing conventional heat-polymerizing PMMA resin with microwave energy resulted in a significant decrease in flexural strength. The results of this study suggest that clinicians may benefit from using heat polymerization when processing PMMA denture bases instead of microvawe polymerization when tested brand is used. PMID:29657535

Direct Quantum Mechanical Simulations of Shocked Energetic Materials

DTIC Science & Technology

2008-12-01

dynamics (QMD) simulations of shocked pentaerythritol tetranitrate (PETN), a conventional high explosive , and the polymeric cubic gauche phase of...nitrogen (cg-N), proposed as an environmentally acceptable energetic alternative to conventional explosive formulations. These simulations, made...stored structural potential energy can be liberated quickly enough, it is possible that explosion can occur with energies several orders of magnitude

Estimation of degree of polymerization of poly-acrylonitrile-grafted carbon nanotubes using Guinier plot of small angle x-ray scattering

NASA Astrophysics Data System (ADS)

Cho, Hyunjung; Jin, Kyeong Sik; Lee, Jaegeun; Lee, Kun-Hong

2018-07-01

Small angle x-ray scattering (SAXS) was used to estimate the degree of polymerization of polymer-grafted carbon nanotubes (CNTs) synthesized using a ‘grafting from’ method. This analysis characterizes the grafted polymer chains without cleaving them from CNTs, and provides reliable data that can complement conventional methods such as thermogravimetric analysis or transmittance electron microscopy. Acrylonitrile was polymerized from the surface of the CNTs by using redox initiation to produce poly-acrylonitrile-grafted CNTs (PAN-CNTs). Polymerization time and the initiation rate were varied to control the degree of polymerization. Radius of gyration (R g ) of PAN-CNTs was determined using the Guinier plot obtained from SAXS solution analysis. The results showed consistent values according to the polymerization condition, up to a maximum R g = 125.70 Å whereas that of pristine CNTs was 99.23 Å. The dispersibility of PAN-CNTs in N,N-dimethylformamide was tested using ultraviolet–visible-near infrared spectroscopy and was confirmed to increase as the degree of polymerization increased. This analysis will be helpful to estimate the degree of polymerization of any polymer-grafted CNTs synthesized using the ‘grafting from’ method and to fabricate polymer/CNT composite materials.

Estimation of degree of polymerization of poly-acrylonitrile-grafted carbon nanotubes using Guinier plot of small angle x-ray scattering.

PubMed

Cho, Hyunjung; Jin, Kyeong Sik; Lee, Jaegeun; Lee, Kun-Hong

2018-07-06

Small angle x-ray scattering (SAXS) was used to estimate the degree of polymerization of polymer-grafted carbon nanotubes (CNTs) synthesized using a 'grafting from' method. This analysis characterizes the grafted polymer chains without cleaving them from CNTs, and provides reliable data that can complement conventional methods such as thermogravimetric analysis or transmittance electron microscopy. Acrylonitrile was polymerized from the surface of the CNTs by using redox initiation to produce poly-acrylonitrile-grafted CNTs (PAN-CNTs). Polymerization time and the initiation rate were varied to control the degree of polymerization. Radius of gyration (R g ) of PAN-CNTs was determined using the Guinier plot obtained from SAXS solution analysis. The results showed consistent values according to the polymerization condition, up to a maximum R g  = 125.70 Å whereas that of pristine CNTs was 99.23 Å. The dispersibility of PAN-CNTs in N,N-dimethylformamide was tested using ultraviolet-visible-near infrared spectroscopy and was confirmed to increase as the degree of polymerization increased. This analysis will be helpful to estimate the degree of polymerization of any polymer-grafted CNTs synthesized using the 'grafting from' method and to fabricate polymer/CNT composite materials.

The White test: a new dye test for intraoperative detection of bile leakage during major liver resection.

PubMed

Nadalin, Silvio; Li, Jun; Lang, Hauke; Sotiropoulos, Georgios C; Schaffer, Randolph; Radtke, Arnold; Saner, Fuat; Broelsch, Christoph E; Malagó, Massimo

2008-04-01

To describe a new intraoperative bile leakage test in patients undergoing a major liver resection aimed to combine the advantages of each of the other standard bile leakage tests (accurate visualization of leaks, reproducibility, and ease of use) without their disadvantages. At the end of the major hepatic resection, 10 to 30 mL of sterile fat emulsion, 5%, is injected via an olive-tip cannula through the cystic duct while manually occluding the distal common bile duct. As the biliary tree fills with fat emulsion solution, leakage of the white fluid is visualized on the raw surface of the liver resection margin. The detected leakages are closed by means of single stitches. Afterwards, the residual fat emulsion on the resection surface is washed off with saline and the White test is repeated to detect and/or exclude additional bile leakages. At the end, residual fat emulsion is washed out from the biliary tract by a low-pressure infusion of saline solution. Intraoperatively, additional potential bile leakages (not seen using a conventional saline bile leakage test) were identified in 74% of our patients. Postoperative bile leakages (within 30 days) occurred in only 5.1% of patients when the White test was used. No adverse effects related to this technique were observed. The White test has clear advantages in comparison with other bile leakage tests: it precisely detects bile leakages, regardless of size; it does not stain the resection surface, allowing it to be washed off and repeated ad infinitum; and it is safe, quick, and inexpensive.

Analytical Characterization of an Oil-in-Water Adjuvant Emulsion.

PubMed

Sun, Jenny; Remmele, Richard L; Sanyal, Gautam

2017-07-01

Adjuvants are typically used in subunit vaccine formulations to enhance immune responses elicited by individual antigens. Physical chemical characterization of novel adjuvants is an important step in ensuring their effective use in vaccine formulations. This paper reports application of a panel of quantitative assays developed to analyze and characterize an oil-in-water adjuvant emulsion, which contains glucopyranosyl lipid A (GLA) and is a squalene-based emulsion. GLA is a fully synthetic analogue of monophosphoryl lipid A, which is a Toll-like receptor type 4 agonist and an FDA-approved adjuvant. The GLA-stable emulsion (GLA-SE) is currently being used for a respiratory syncytial virus vaccine in a phase 2 clinical trial. GLA was quantitated using reverse-phased high-performance liquid chromatography (RP-HPLC) coupled to a mass spectrometric detector, achieving higher assay sensitivity than the charged aerosol detection routinely used. Quantitation of the excipients of GLA-SE, including squalene, egg phosphatidyl choline, and Poloxamer 188, was achieved using a simple and rapid RP-HPLC method with evaporative light scattering detection, eliminating chemical derivatization typically required for these chromophore-lacking compounds. DL-α-tocopherol, the antioxidant of the GLA-SE, was quantitated using a RP-HPLC method with conventional UV detection. The experimental results compared well with values expected for these compounds based on targeted composition of the adjuvant. The assays were applied to identify degradation of individual components in a GLA-SE sample that degraded into distinct aqueous and oil phases. The methods developed and reported here are effective tools in monitoring physicochemical integrity of the adjuvant, as well as in formulation studies.

Microhardness of resin composites polymerized by plasma arc or conventional visible light curing.

PubMed

Park, S Ho; Krejci, I; Lutz, F

2002-01-01

This study evaluated the effectiveness of the plasma arc curing (PAC) unit for composite curing. To compare its effectiveness with conventional quartz tungsten halogen (QTH) light curing units, the microhardness of two composites (Z100 and Tetric Ceram) that had been light cured by the PAC or QTH units, were compared according to the depth from the composite surface. In addition, linear polymerization shrinkage was compared using a custom-made linometer between composites which were light cured by PAC or QTH units. Measuring polymerization shrinkage for two resin composites (Z100 and Tetric Ceram) was performed after polymerization with either QTH or PAC units. In the case of curing with the PAC unit, the composite was light cured with Apollo 95E for two (Group 1), three (Group 2), six (Group 3) or 2 x 6 (Group 4) seconds. For light curing with the QTH unit, the composite was light cured for 60 seconds with Optilux 500 (Group 5). The linear polymerization shrinkage of composites was determined in the linometer. Two resin composites were used to measure microhardness. Two-mm thick samples were light cured for three seconds (Group 1), six seconds (Group 2) or 12 (2 x 6) seconds (Group 3) with Apollo 95E or they were conventionally light cured with Optilux 500 for 30 seconds (Group 4) or 60 seconds (Group 5). For 3 mm thick samples, the composites were light cured for six seconds (Group 1), 12 (2 x 6) seconds (Group 2) or 18 (3 x 6) seconds (Group 3) with Apollo 95E or they were conventionally light cured with Optilux 500 for 30 seconds (Group 4) or 60 seconds (Group 5). Twenty samples were assigned to each group. The microhardness of the upper and lower surfaces was measured with a Vickers hardness-measuring instrument under load. The difference in microhardness between the upper and lower surfaces in each group was analyzed by paired t-test. For the upper or lower surfaces, one-way ANOVA with Tukey was used. For Tetric Ceram, the amount of polymerization shrinkage was lower when cured with the Apollo 95E for two or three seconds than when cured for six and 12 (2 x 6) seconds, or for 60 seconds with Optilux 500 (p<0.05). For Z100, the amount of linear polymerization shrinkage was lower when cured with the Apollo 95E for two, three and six seconds than for 12 (2 x 6) seconds with Apollo 95E or for 60 seconds with the Optilux 500 (p<0.05). The results of the microhardness test indicated that there was no statistically significant difference in microhardness between groups for the upper surface. However, for the lower surface, when the composites were light cured with Apollo 95E for three seconds as recommended by the manufacturer, microhardness of the lower surface was usually lower than that of the upper surface and did not cure sufficiently. Conclusively, when compared with conventional QTH unit, the PAC unit, Apollo 95E did not properly cure the lower composite surface when the layer thickness exceeded 2 mm. In addition, three seconds of curing time, which the manufacturer recommended, was insufficient for optimal curing of composites.

Effects of parenteral structured lipid emulsion on modulating the inflammatory response in rats undergoing a total gastrectomy.

PubMed

Lin, Ming-Tsan; Yeh, Sung-Ling; Tsou, Shung-Sheng; Wang, Ming-Yang; Chen, Wei-Jao

2009-01-01

Structured lipid emulsion improves the nitrogen balance and is rapidly cleared from the blood of moderately catabolic patients. However, the effects of structured lipids on inflammatory reactions during major surgery are not clear. This study investigated the effect of a parenteral structured triacylglycerol emulsion on leukocyte adhesion molecule expression and inflammatory mediator production in rats undergoing a total gastrectomy. Normal rats with internal jugular catheters were assigned to three experimental groups and received total parenteral nutrition. At the same time, a total gastrectomy was performed on the experimental groups. The total parenteral nutrition solutions were isonitrogenous and identical in nutrient compositions except for differences in the composition of the fat emulsion. Group 1 received a conventional fat emulsion with long-chain triacylglycerols (LCTs), group 2 received a physical mixture of medium-chain triacylglycerols (MCTs) and LCTs (MCT/LCT), and group 3 received structured lipids composed of MCTs and LCTs (STG). Half of the rats in each respective group were sacrificed 1 d and the other half 3 d after surgery to examine the analytical parameters. Plasma cholesterol and free fatty acid levels in the STG group were lower than those in the other groups after surgery. The STG group had lower leukocyte CD11a/CD18 expressions than the MCT/LCT group 3 d after surgery, and CD11b/CD18 expressions in the STG group were lower than those in the LCT group on postoperative days. The STG group had higher monocyte chemotactic protein-1 and macrophage inflammatory protein-2 levels in peritoneal lavage fluid than did the other two groups. These results suggest that, compared with the LCT and MCT/LCT groups, rats administered STG had lower plasma lipid concentrations and leukocyte integrin expressions. In addition, STG administration may cause increased recruiting of neutrophils and monocytes at the site of injury and enhance antipathogenicity in rats undergoing a total gastrectomy.

Composite polymeric film and method for its use in installing a very-thin polymeric film in a device

DOEpatents

Duchane, D.V.; Barthell, B.L.

1982-04-26

A composite polymeric film and a method for its use in forming and installing a very thin (< 10 ..mu..m) polymeric film are disclosed. The composite film consists of a thin film layer and a backing layer. The backing layer is soluble in a solvent in which the thin film layer is not soluble. In accordance with the method, the composite film is installed in a device in the same position in which it is sought to finally emplace the thin film. The backing layer is then selectiely dissolved in the solvent to leave the insoluble thin film layer as an unbacked film. The method permits a very thin film to e successfully installed in devices where the fragility of the film would preclude handling and installation by conventional methods.

Composite polymeric film and method for its use in installing a very thin polymeric film in a device

DOEpatents

Duchane, David V.; Barthell, Barry L.

1984-01-01

A composite polymeric film and a method for its use in forming and installing a very thin (<10 .mu.m) polymeric film are disclosed. The composite film consists of a thin film layer and a backing layer. The backing layer is soluble in a solvent in which the thin film layer is not soluble. In accordance with the method, the composite film is installed in a device in the same position in which it is sought to finally emplace the thin film. The backing layer is then selectively dissolved in the solvent to leave the insoluble thin film layer as an unbacked film. The method permits a very thin film to be successfully installed in devices where the fragility of the film would preclude handling and installation by conventional methods.

Versatile Tandem Ring-Opening/Ring-Closing Metathesis Polymerization: Strategies for Successful Polymerization of Challenging Monomers and Their Mechanistic Studies.

PubMed

Park, Hyeon; Kang, Eun-Hye; Müller, Laura; Choi, Tae-Lim

2016-02-24

Tandem ring-opening/ring-closing metathesis (RO/RCM) results in extremely fast living polymerization; however, according to previous reports, only monomers containing certain combinations of cycloalkenes, terminal alkynes, and nitrogen linkers successfully underwent tandem polymerization. After examining the polymerization pathways, we proposed that the relatively slow intramolecular cyclization might lead to competing side reactions such as intermolecular cross metathesis reactions to form inactive propagating species. Thus, we developed two strategies to enhance tandem polymerization efficiency. First, we modified monomer structures to accelerate tandem RO/RCM cyclization by enhancing the Thorpe-Ingold effect. This strategy increased the polymerization rate and suppressed the chain transfer reaction to achieve controlled polymerization, even for challenging syntheses of dendronized polymers. Alternatively, reducing the reaction concentration facilitated tandem polymerization, suggesting that the slow tandem RO/RCM cyclization step was the main reason for the previous failure. To broaden the monomer scope, we used monomers containing internal alkynes and observed that two different polymer units with different ring sizes were produced as a result of nonselective α-addition and β-addition on the internal alkynes. Thorough experiments with various monomers with internal alkynes suggested that steric and electronic effects of the alkyne substituents influenced alkyne addition selectivity and the polymerization reactivity. Further polymerization kinetics studies revealed that the rate-determining step of monomers containing certain internal alkynes was the six-membered cyclization step via β-addition, whereas that for other monomers was the conventional intermolecular propagation step, as observed in other chain-growth polymerizations. This conclusion agrees well with all those polymerization results and thus validates our strategies.

Water-soluble polymers bearing phosphorylcholine group and other zwitterionic groups for carrying DNA derivatives.

PubMed

Lin, Xiaojie; Ishihara, Kazuhiko

2014-01-01

Water-soluble polymers with equal positive and negative charges in the same monomer unit, such as the phosphorylcholine group and other zwitterionic groups, exhibit promising potential in gene delivery with appreciable transfection efficiency, compared with the traditional poly(ethylene glycol)-based polycation-gene complexes. These zwitterionic polymers with various architectural structures and properties have been synthesized by various polymerization methods, such as conventional radical polymerization, atom-transfer radical-polymerization, reversible addition-fragmentation chain-transfer polymerization, and nitroxide-mediated radical polymerization. These techniques have been used to efficiently facilitate gene therapy by fabrication of non-viral vectors with high cytocompatibility, large gene-carrying capacity, effective cell-membrane permeability, and in vivo gene-loading/releasing functionality. Zwitterionic polymer-based gene delivery vectors systems can be categorized into soluble-polymer/gene mixing, molecular self-assembly, and polymer-gene conjugation systems. This review describes the preparation and characterization of various zwitterionic polymer-based gene delivery vectors, specifically water-soluble phospholipid polymers for carrying gene derivatives.

Hydroperoxide Traces in Common Cyclic Ethers as Initiators for Controlled RAFT Polymerizations.

PubMed

Eggers, Steffen; Abetz, Volker

2018-04-01

Herein, a reversible addition-fragmentation chain transfer (RAFT) polymerization is introduced for reactive monomers like N-acryloylpyrrolidine or N,N-dimethylacrylamide working without a conventional radical initiator. As a very straightforward proof of principle, the method takes advantage of the usually inconvenient radical-generating hydroperoxide contaminations in cyclic ethers like tetrahydrofuran or 1,4-dioxane, which are very common solvents in polymer sciences. The polymerizations are surprisingly well controlled and the polymers can be extended with a second block, indicating their high livingness. "Solvent-initiated" RAFT polymerizations hence prove to be a feasible access to tailored materials with minimal experimental effort and standard laboratory equipment, only requiring the following ingredients: hydroperoxide-contaminated solvent, monomer, and RAFT agent. In other respects, however, the potential coinitiating ability of the used solvent is to be considered when investigating the kinetics of RAFT polymerizations or aiming for the synthesis of high-livingness polymers, e.g., multiblock copolymers. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid quantification of inflammation in tissue samples using perfluorocarbon emulsion and fluorine-19 nuclear magnetic resonance

PubMed Central

Ahrens, Eric T.; Young, Won-Bin; Xu, Hongyan; Pusateri, Lisa K.

2016-01-01

Quantification of inflammation in tissue samples can be a time-intensive bottleneck in therapeutic discovery and preclinical endeavors. We describe a versatile and rapid approach to quantitatively assay macrophage burden in intact tissue samples. Perfluorocarbon (PFC) emulsion is injected intravenously, and the emulsion droplets are effectively taken up by monocytes and macrophages. These ‘in situ’ labeled cells participate in inflammatory events in vivo resulting in PFC accumulation at inflammatory loci. Necropsied tissues or intact organs are subjected to conventional fluorine-19 (19F) NMR spectroscopy to quantify the total fluorine content per sample, proportional to the macrophage burden. We applied these methods to a rat model of experimental allergic encephalomyelitis (EAE) exhibiting extensive inflammation and demyelination in the central nervous system (CNS), particularly in the spinal cord. In a cohort of EAE rats, we used 19F NMR to derive an inflammation index (IFI) in intact CNS tissues. Immunohistochemistry was used to confirm intracellular colocalization of the PFC droplets within CNS CD68+ cells having macrophage morphology. The IFI linearly correlated to mRNA levels of CD68 via real-time PCR analysis. This 19F NMR approach can accelerate tissue analysis by at least an order of magnitude compared with histological approaches. PMID:21548906

The effect of low-fat beef patties formulated with a low-energy fat analogue enriched in long-chain polyunsaturated fatty acids on lipid oxidation and sensory attributes.

PubMed

Alejandre, Marta; Passarini, Denis; Astiasarán, Iciar; Ansorena, Diana

2017-12-01

A new low-energy gelled emulsion containing algae oil was developed as animal fat replacer. Its stability was evaluated under different storage conditions: 4V (4°C/vacuum), 4NV (4°C/no vacuum), 25V (25°C/vacuum) and 25NV (25°C/no vacuum). According to moisture, hardness, color and lipid oxidation data, 4°C under vacuum (4V) was selected as the best condition. Once the gelled emulsion was characterized, its effectiveness as fat analogue was demonstrated in beef patties. Reformulated patties were produced with 100% of animal fat replacement and compared to conventional patties (9%fat). A 70%fat reduction was achieved in the new patties, mainly due to a reduction in the saturated fatty acids. Also, decreased n-6 (76%lower content) and increased eicosapentaenoic and docosahexaenoic acids (55%higher content) were noticed in the new formulation. The incorporation of the gelled emulsion containing reduced amount of n-6 fatty acids and increased amounts of long chain n-3 fatty acids (EPA+DHA) reduced the oxidation status of the patties and their sensory evaluation resulted in acceptable scores. Copyright © 2017 Elsevier Ltd. All rights reserved.

A Geant Study of the Scintillating Optical Fiber (SOFCAL) Cosmic Ray Detector

NASA Technical Reports Server (NTRS)

Munroe, Ray B., Jr.

1998-01-01

Recent energy measurements by balloon-borne passive emulsion chambers indicate that the flux ratios of protons to helium nuclei and of protons to all heavy nuclei decrease as the primary cosmic ray energy per nucleon increases above approx. 200 GeV/n, and suggest a "break" in the proton spectrum between 200 GeV and 5 TeV. However, these passive emulsion chambers are limited to a lower energy threshold of approx. 5 TeV/n, and cannot fully explore this energy regime. Because cosmic ray flux and composition details may be significant to acceleration models, a hybrid detector system called the Scintillating Optical Fiber Calorimeter (SOFCAL) has been designed and flown. SOFCAL incorporates both conventional passive emulsion chambers and an active calorimeter utilizing scintillating plastic fibers as detectors. These complementary types of detectors allow the balloon-borne SOFCAL experiment to measure the proton and helium spectra from approx. 400 GeV/n to approx. 20 TeV. The fundamental purpose of this study is to use the GEANT simulation package to model the hadronic and electromagnetic shower evolution of cosmic rays incident on the SOFCAL detector. This allows the interpretation of SOFCAL data in terms of charges and primary energies of cosmic rays, thus allowing the determinations of cosmic ray flux and composition as functions of primary energy.

Formulation of nanotized curcumin and demonstration of its antimalarial efficacy

PubMed Central

Ghosh, Aparajita; Banerjee, Tanushree; Bhandary, Suman; Surolia, Avadhesha

2014-01-01

Aim The present study was conducted to overcome the disadvantages associated with the poor water solubility and low bioavailability of curcumin by synthesizing nanotized curcumin and demonstrating its efficacy in treating malaria. Materials and methods Nanotized curcumin was prepared by a modified emulsion-diffusion-evaporation method and was characterized by means of transmission electron microscopy, atomic force microscopy, dynamic light scattering, Zetasizer, Fourier transform infrared spectroscopy, and differential thermal analysis. The novelty of the prepared nanoformulation lies in the fact that it was devoid of any polymeric matrices used in conventional carriers. The antimalarial efficacy of the prepared nanotized curcumin was then checked both in vitro and in vivo. Results The nanopreparation was found to be non-toxic and had a particle size distribution of 20–50 nm along with improved aqueous dispersibility and an entrapment efficiency of 45%. Nanotized curcumin (half maximal inhibitory concentration [IC50]: 0.5 μM) was also found to be ten-fold more effective for growth inhibition of Plasmodium falciparum in vitro as compared to its native counterpart (IC50: 5 μM). Oral bioavailability of nanotized curcumin was found to be superior to that of its native counterpart. Moreover, when Plasmodium berghei-infected mice were orally treated with nanotized curcumin, it prolonged their survival by more than 2 months with complete clearance of parasites in comparison to the untreated animals, which survived for 8 days only. Conclusion Nanotized curcumin holds a considerable promise in therapeutics as demonstrated here for treating malaria as a test system. PMID:25484584

Synthesis and characterization of monodispersed polymer/polydiacetylene nanocrystal composite particles.

PubMed

Wei, Zhong; Ujiiye-Ishii, Kento; Masuhara, Akito; Kasai, Hitoshi; Okada, Shuji; Matsune, Hideki; Asahi, Tsuyoshi; Masuhara, Hiroshi; Nakanishi, Hachiro

2005-06-01

Monodispersed polymer/polydiacetylenecomposite particles were synthesized by soap-free seeded emulsion polymerization of styrene andmethyl methacrylate; the products were characterized by XRD, SEM, TEM, UV-visible spectroscopy, and single particle scattering spectroscopy. In the synthesis process, polydiacetylene nanocrystals were found to act as inhibitor, and consequently a relatively low concentration was necessary. Different monomers lead to the differences in reaction condition and particle morphology; the PMMA composite particles were simpler in preparation than polystyrene particles, but the latter havebetter spherical morphology. The composite particles were composed of polymer shells and polydiacetylene cores, which kept their crystal structure and optical properties. A high percentage of cored particles could be achieved with optimized reaction conditions where the amount of seed was sufficient and the oily oligomer by-product was suppressed.

Scaffolds for Controlled Release of Cartilage Growth Factors.

PubMed

Morille, Marie; Venier-Julienne, Marie-Claire; Montero-Menei, Claudia N

2015-01-01

In recent years, cell-based therapies using adult stem cells have attracted considerable interest in regenerative medicine. A tissue-engineered construct for cartilage repair should provide a support for the cell and allow sustained in situ delivery of bioactive factors capable of inducing cell differentiation into chondrocytes. Pharmacologically active microcarriers (PAMs), made of biodegradable and biocompatible poly (D,L-lactide-co-glycolide acid) (PLGA), are a unique system which combines these properties in an adaptable and simple microdevice. This device relies on nanoprecipitation of proteins encapsulated in polymeric microspheres with a solid in oil in water emulsion-solvent evaporation process, and their subsequent coating with extracellular matrix protein molecules. Here, we describe their preparation process, and some of their characterization methods for an application in cartilage tissue engineering.

Albumin as a "Trojan Horse" for polymeric nanoconjugate transendothelial transport across tumor vasculatures for improved cancer targeting.

PubMed

Yin, Qian; Tang, Li; Cai, Kaimin; Yang, Xujuan; Yin, Lichen; Zhang, Yanfeng; Dobrucki, Lawrence W; Helferich, William G; Fan, Timothy M; Cheng, Jianjun

2018-05-01

Although polymeric nanoconjugates (NCs) hold great promise for the treatment of cancer patients, their clinical utility has been hindered by the lack of efficient delivery of therapeutics to targeted tumor sites. Here, we describe an albumin-functionalized polymeric NC (Alb-NC) capable of crossing the endothelium barrier through a caveolae-mediated transcytosis pathway to better target cancer. The Alb-NC is prepared by nanoprecipitation of doxorubicin (Doxo) conjugates of poly(phenyl O-carboxyanhydrides) bearing aromatic albumin-binding domains followed by subsequent surface decoration of albumin. The administration of Alb-NCs into mice bearing MCF-7 human breast cancer xenografts with limited tumor vascular permeability resulted in markedly increased tumor accumulation and anti-tumor efficacy compared to their conventional counterpart PEGylated NCs (PEG-NCs). The Alb-NC provides a simple, low-cost and broadly applicable strategy to improve the cancer targeting efficiency and therapeutic effectiveness of polymeric nanomedicine.

Imipenem/cilastatin encapsulated polymeric nanoparticles for destroying carbapenem-resistant bacterial isolates.

PubMed

Shaaban, Mona I; Shaker, Mohamed A; Mady, Fatma M

2017-04-11

Carbapenem-resistance is an extremely growing medical threat in antibacterial therapy as the incurable resistant strains easily develop a multi-resistance action to other potent antimicrobial agents. Nonetheless, the protective delivery of current antibiotics using nano-carriers opens a tremendous approach in the antimicrobial therapy, allowing the nano-formulated antibiotics to beat these health threat pathogens. Herein, we encapsulated imipenem into biodegradable polymeric nanoparticles to destroy the imipenem-resistant bacteria and overcome the microbial adhesion and dissemination. Imipenem loaded poly Ɛ-caprolactone (PCL) and polylactide-co-glycolide (PLGA) nanocapsules were formulated using double emulsion evaporation method. The obtained nanocapsules were characterized for mean particle diameter, morphology, loading efficiency, and in vitro release. The in vitro antimicrobial and anti adhesion activities were evaluated against selected imipenem-resistant Klebsiella pneumoniae and Pseudomonas aeruginosa clinical isolates. The obtained results reveal that imipenem loaded PCL nano-formulation enhances the microbial susceptibility and antimicrobial activity of imipenem. The imipenem loaded PCL nanoparticles caused faster microbial killing within 2-3 h compared to the imipenem loaded PLGA and free drug. Successfully, PCL nanocapsules were able to protect imipenem from enzymatic degradation by resistant isolates and prevent the emergence of the resistant colonies, as it lowered the mutation prevention concentration of free imipenem by twofolds. Moreover, the imipenem loaded PCL eliminated bacterial attachment and the biofilm assembly of P. aeruginosa and K. pneumoniae planktonic bacteria by 74 and 78.4%, respectively. These promising results indicate that polymeric nanoparticles recover the efficacy of imipenem and can be considered as a new paradigm shift against multidrug-resistant isolates in treating severe bacterial infections.

Two Photon Polymerization of Microneedles for Transdermal Drug Delivery

PubMed Central

Gittard, Shaun D.; Ovsianikov, Aleksandr; Chichkov, Boris N.; Doraiswamy, Anand; Narayan, Roger J.

2010-01-01

Importance of the field Microneedles are small-scale devices that are finding use for transdermal delivery of protein-based pharmacologic agents and nucleic acid-based pharmacologic agents; however, microneedles prepared using conventional microelectronics-based technologies have several shortcomings, which have limited translation of these devices into widespread clinical use. Areas covered in this review Two photon polymerization is a laser-based rapid prototyping technique that has been recently used for direct fabrication of hollow microneedles with a wide variety of geometries. In addition, an indirect rapid prototyping method that involves two photon polymerization and polydimethyl siloxane micromolding has been used for fabrication of solid microneedles with exceptional mechanical properties. What the reader will gain In this review, the use of two photon polymerization for fabricating in-plane and out-of-plane hollow microneedle arrays is described. The use of two photon polymerization-micromolding for fabrication of solid microneedles is also reviewed. In addition, fabrication of microneedles with antimicrobial properties is discussed; antimicrobial microneedles may reduce the risk of infection associated with formation of channels through the stratum corneum. Take home message It is anticipated that the use of two photon polymerization as well as two photon polymerization-micromolding for fabrication of microneedles and other microstructured drug delivery devices will increase over the coming years. PMID:20205601

Metastable Polymeric Nitrogen: The Ultimate Green High-Energy-Density Material

NASA Astrophysics Data System (ADS)

Ciezak, Jennifer

2007-06-01

High-energy-high-density materials offering increased stability, vulnerability, and environmental safety are being aggressively pursued to meet the requirements of the DoD Joint Visions and Future Force. Nearly two decades ago, it was proposed that polymeric nitrogen would exceed all of these requirements and possess nearly five times the energy of any conventional energetic material in use today. The present study details an investigation into nitrogen polymerization using a novel high-pressure approach utilizing sodium azide as the starting material. Due to the weaker bonding structure of the anionic azide chains in comparison to a N-N triple bond, one expects that the azide chains will create single-covalently bonded polymeric networks more easily than diatomic nitrogen. A polymeric form of sodium azide was synthesized at high pressures, but the material was not metastable at ambient conditions, which precluded performance testing. Quantum chemical calculations have indicated stabilization of the polymeric structure at ambient conditions may be possible with the addition of hydrogen. Vibrational spectroscopic characterization suggests that a meta-stable polymeric form of nitrogen has been synthesized under high-pressure using sodium azide/hydrogen as the starting materials. This material remains stable at ambient conditions upwards of two weeks depending on the storage conditions.

Improved insulin loading in poly(lactic-co-glycolic) acid (PLGA) nanoparticles upon self-assembly with lipids.

PubMed

García-Díaz, María; Foged, Camilla; Nielsen, Hanne Mørck

2015-03-30

Polymeric nanoparticles are widely investigated as drug delivery systems for oral administration. However, the hydrophobic nature of many polymers hampers effective loading of the particles with hydrophilic macromolecules such as insulin. Thus, the aim of this work was to improve the loading of insulin into poly(lactic-co-glycolic) acid (PLGA) nanoparticles by pre-assembly with amphiphilic lipids. Insulin was complexed with soybean phosphatidylcholine or sodium caprate by self-assembly and subsequently loaded into PLGA nanoparticles by using the double emulsion-solvent evaporation technique. The nanoparticles were characterized in terms of size, zeta potential, insulin encapsulation efficiency and loading capacity. Upon pre-assembly with lipids, there was an increased distribution of insulin into the organic phase of the emulsion, eventually resulting in significantly enhanced encapsulation efficiencies (90% as compared to 24% in the absence of lipids). Importantly, the insulin loading capacity was increased up to 20% by using the lipid-insulin complexes. The results further showed that a main fraction of the lipid was incorporated into the nanoparticles and remained associated to the polymer during release studies in buffers, whereas insulin was released in a non-complexed form as a burst of approximately 80% of the loaded insulin. In conclusion, the protein load in PLGA nanoparticles can be significantly increased by employing self-assembled protein-lipid complexes. Copyright © 2014 Elsevier B.V. All rights reserved.

Polymeric nanoparticles containing diazepam: preparation, optimization, characterization, in-vitro drug release and release kinetic study

NASA Astrophysics Data System (ADS)

Bohrey, Sarvesh; Chourasiya, Vibha; Pandey, Archna

2016-03-01

Nanoparticles formulated from biodegradable polymers like poly(lactic-co-glycolic acid) (PLGA) are being extensively investigated as drug delivery systems due to their two important properties such as biocompatibility and controlled drug release characteristics. The aim of this work to formulated diazepam loaded PLGA nanoparticles by using emulsion solvent evaporation technique. Polyvinyl alcohol (PVA) is used as stabilizing agent. Diazepam is a benzodiazepine derivative drug, and widely used as an anticonvulsant in the treatment of various types of epilepsy, insomnia and anxiety. This work investigates the effects of some preparation variables on the size and shape of nanoparticles prepared by emulsion solvent evaporation method. These nanoparticles were characterized by photon correlation spectroscopy (PCS), transmission electron microscopy (TEM). Zeta potential study was also performed to understand the surface charge of nanoparticles. The drug release from drug loaded nanoparticles was studied by dialysis bag method and the in vitro drug release data was also studied by various kinetic models. The results show that sonication time, polymer content, surfactant concentration, ratio of organic to aqueous phase volume, and the amount of drug have an important effect on the size of nanoparticles. Hopefully we produced spherical shape Diazepam loaded PLGA nanoparticles with a size range under 250 nm with zeta potential -23.3 mV. The in vitro drug release analysis shows sustained release of drug from nanoparticles and follow Korsmeyer-Peppas model.

Charge patterns as templates for the assembly of layered biomolecular structures.

PubMed

Naujoks, Nicola; Stemmer, Andreas

2006-08-01

Electric fields are used to guide the assembly of biomolecules in predefined geometric patterns on solid substrates. Local surface charges serve as templates to selectively position proteins on thin-film polymeric electret layers, thereby creating a basis for site-directed layered assembly of biomolecular structures. Charge patterns are created using the lithographic capabilities of an atomic force microscope, namely by applying voltage pulses between a conductive tip and the sample. Samples consist of a poly(methyl methacrylate) layer on a p-doped silicon support. Subsequently, the sample is developed in a water-in-oil emulsion, consisting of a dispersed aqueous phase containing biotin-modified immunoglobulinG molecules, and a continuous nonpolar, insulating oil phase. The electrostatic fields cause a net force of (di)electrophoretic nature on the droplet, thereby guiding the proteins to the predefined locations. Due to the functionalization of the immunoglobulinG molecules with biotin-groups, these patterns can now be used to initiate the localized layer-by-layer assembly of biomolecules based on the avidin-biotin mechanism. By binding 40 nm sized biotin-labelled beads to the predefined locations via a streptavidin linker, we verify the functionality of the previously deposited immunoglobulinG-biotin. All assembly steps following the initial deposition of the immunoglobulinG from emulsion can conveniently be conducted in aqueous solutions. Results show that pattern definition is maintained after immersion into aqueous solution.

Facile Preparation of Internally Self-assembled Lipid Particles Stabilized by Carbon Nanotubes

PubMed Central

Patil-Sen, Yogita; Sadeghpour, Amin; Rappolt, Michael; Kulkarni, Chandrashekhar V.

2016-01-01

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled (functionalized) CNTs are used as stabilizers to produce Pickering type oil-in-water (O/W) emulsions. Lipids namely, Dimodan U and Phytantriol are used as emulsifiers, which in excess water self-assemble into the bicontinuous cubic Pn3m phase. This highly viscous phase is fragmented into smaller particles using a probe ultrasonicator in presence of conventional surfactant stabilizers or CNTs as done here. Initially, the CNTs (powder form) are dispersed in water followed by further ultrasonication with the molten lipid to form the final emulsion. During this process the CNTs get coated with lipid molecules, which in turn are presumed to surround the lipid droplets to form a particulate emulsion that is stable for months. The average size of CNT-stabilized nanostructured lipid particles is in the submicron range, which compares well with the particles stabilized using conventional surfactants. Small angle X-ray scattering data confirms the retention of the original Pn3m cubic phase in the CNT-stabilized lipid dispersions as compared to the pure lipid phase (bulk state). Blue shift and lowering of the intensities in characteristic G and G' bands of CNTs observed in Raman spectroscopy characterize the interaction between CNT surface and lipid molecules. These results suggest that the interactions between the CNTs and lipids are responsible for their mutual stabilization in aqueous solutions. As the concentrations of CNTs employed for stabilization are very low and lipid molecules are able to functionalize the CNTs, the toxicity of CNTs is expected to be insignificant while their biocompatibility is greatly enhanced. Hence the present approach finds a great potential in various biomedical applications, for instance, for developing hybrid nanocarrier systems for the delivery of multiple functional molecules as in combination therapy or polytherapy. PMID:26967650

Facile Preparation of Internally Self-assembled Lipid Particles Stabilized by Carbon Nanotubes.

PubMed

Patil-Sen, Yogita; Sadeghpour, Amin; Rappolt, Michael; Kulkarni, Chandrashekhar V

2016-02-19

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled (functionalized) CNTs are used as stabilizers to produce Pickering type oil-in-water (O/W) emulsions. Lipids namely, Dimodan U and Phytantriol are used as emulsifiers, which in excess water self-assemble into the bicontinuous cubic Pn3m phase. This highly viscous phase is fragmented into smaller particles using a probe ultrasonicator in presence of conventional surfactant stabilizers or CNTs as done here. Initially, the CNTs (powder form) are dispersed in water followed by further ultrasonication with the molten lipid to form the final emulsion. During this process the CNTs get coated with lipid molecules, which in turn are presumed to surround the lipid droplets to form a particulate emulsion that is stable for months. The average size of CNT-stabilized nanostructured lipid particles is in the submicron range, which compares well with the particles stabilized using conventional surfactants. Small angle X-ray scattering data confirms the retention of the original Pn3m cubic phase in the CNT-stabilized lipid dispersions as compared to the pure lipid phase (bulk state). Blue shift and lowering of the intensities in characteristic G and G' bands of CNTs observed in Raman spectroscopy characterize the interaction between CNT surface and lipid molecules. These results suggest that the interactions between the CNTs and lipids are responsible for their mutual stabilization in aqueous solutions. As the concentrations of CNTs employed for stabilization are very low and lipid molecules are able to functionalize the CNTs, the toxicity of CNTs is expected to be insignificant while their biocompatibility is greatly enhanced. Hence the present approach finds a great potential in various biomedical applications, for instance, for developing hybrid nanocarrier systems for the delivery of multiple functional molecules as in combination therapy or polytherapy.

JP-8 and Other Military Fuels

DTIC Science & Technology

2011-12-01

Fermentation Jet Fuel-Like Product sugarcane Alcohol Oligomerization Conventional Refinery ProcessesSugar switchgrass Dehydration Pyrolysis Fermentation...PolymerizationOlefins Lignocellulose corn stover forest waste Jet Fuel-Like ProductBio-CrudePyrolysis Hydroprocessing Unclassified Back Up Slides

Effect of Polymer Electrode Morphology on Performance of a Lithium/Polypyrrole Battery. M.S. Thesis

NASA Technical Reports Server (NTRS)

Nicholson, Marjorie Anne

1991-01-01

A variety of conducting polymer batteries were described in the recent literature. In this work, a Li/Polypyrrole secondary battery is described. The effect of controlling the morphology of the polymer on enhancement of counterion diffusion in the polymer phase is explored. A method of preparing conducting polymers was developed which yields high surface area per unit volume of electrode material. A porous membrane is used as a template in which to electrochemically polymerize pyrrole, then the membrane is dissolved, leaving the polymer in a fibrillar form. Conventionally, the polymer is electrochemically polymerized as a dense polymer film on a smooth Pt disk electrode. Previous work has shown that when the polymer is electrochemically polymerized in fribrillar form, charge transport rates are faster and charge capacities are greater than for dense, conventionally grown films containing the same amount of polymer. The purpose is to expand previous work by further investigating the possibilities of the optimization of transport rates in polypyrrole films by controlling the morphology of the films. The utility of fibrillar polypyrrole as a cathode material in a lithium/polymer secondary battery is then assessed. The performance of the fibrillar battery is compared to the performance of an analogous battery which employed a conventionally grown polypyrrole film. The study includes a comparison of cyclic voltammetry, shape of charge/discharge curves, discharge time and voltage, cycle life, coulombic efficiencies, charge capacities, energy densities, and energy efficiencies.

Design Space Approach for Preservative System Optimization of an Anti-Aging Eye Fluid Emulsion.

PubMed

Lourenço, Felipe Rebello; Francisco, Fabiane Lacerda; Ferreira, Márcia Regina Spuri; Andreoli, Terezinha De Jesus; Löbenberg, Raimar; Bou-Chacra, Nádia

2015-01-01

The use of preservatives must be optimized in order to ensure the efficacy of an antimicrobial system as well as the product safety. Despite the wide variety of preservatives, the synergistic or antagonistic effects of their combinations are not well established and it is still an issue in the development of pharmaceutical and cosmetic products. The purpose of this paper was to establish a space design using a simplex-centroid approach to achieve the lowest effective concentration of 3 preservatives (methylparaben, propylparaben, and imidazolidinyl urea) and EDTA for an emulsion cosmetic product. Twenty-two formulae of emulsion differing only by imidazolidinyl urea (A: 0.00 to 0.30% w/w), methylparaben (B: 0.00 to 0.20% w/w), propylparaben (C: 0.00 to 0.10% w/w) and EDTA (D: 0.00 to 0.10% w/w) concentrations were prepared. They were tested alone and in binary, ternary and quaternary combinations. Aliquots of these formulae were inoculated with several microorganisms. An electrochemical method was used to determine microbial burden immediately after inoculation and after 2, 4, 8, 12, 24, 48, and 168 h. An optimization strategy was used to obtain the concentrations of preservatives and EDTA resulting in a most effective preservative system of all microorganisms simultaneously. The use of preservatives and EDTA in combination has the advantage of exhibiting a potential synergistic effect against a wider spectrum of microorganisms. Based on graphic and optimization strategies, we proposed a new formula containing a quaternary combination (A: 55%; B: 30%; C: 5% and D: 10% w/w), which complies with the specification of a conventional challenge test. A design space approach was successfully employed in the optimization of concentrations of preservatives and EDTA in an emulsion cosmetic product.

Correlation of porous and functional properties of food materials by NMR relaxometry and multivariate analysis.

PubMed

Haiduc, Adrian Marius; van Duynhoven, John

2005-02-01

The porous properties of food materials are known to determine important macroscopic parameters such as water-holding capacity and texture. In conventional approaches, understanding is built from a long process of establishing macrostructure-property relations in a rational manner. Only recently, multivariate approaches were introduced for the same purpose. The model systems used here are oil-in-water emulsions, stabilised by protein, and form complex structures, consisting of fat droplets dispersed in a porous protein phase. NMR time-domain decay curves were recorded for emulsions with varied levels of fat, protein and water. Hardness, dry matter content and water drainage were determined by classical means and analysed for correlation with the NMR data with multivariate techniques. Partial least squares can calibrate and predict these properties directly from the continuous NMR exponential decays and yields regression coefficients higher than 82%. However, the calibration coefficients themselves belong to the continuous exponential domain and do little to explain the connection between NMR data and emulsion properties. Transformation of the NMR decays into a discreet domain with non-negative least squares permits the use of multilinear regression (MLR) on the resulting amplitudes as predictors and hardness or water drainage as responses. The MLR coefficients show that hardness is highly correlated with the components that have T2 distributions of about 20 and 200 ms whereas water drainage is correlated with components that have T2 distributions around 400 and 1800 ms. These T2 distributions very likely correlate with water populations present in pores with different sizes and/or wall mobility. The results for the emulsions studied demonstrate that NMR time-domain decays can be employed to predict properties and to provide insight in the underlying microstructural features.

Effect of House Cricket (Acheta domesticus) Flour Addition on Physicochemical and Textural Properties of Meat Emulsion Under Various Formulations.

PubMed

Kim, Hyun-Wook; Setyabrata, Derico; Lee, YongJae; Jones, Owen G; Kim, Yuan H Brad

2017-12-01

The objective of this study was to determine the effect of house cricket (Acheta domesticus) flour addition on physicochemical and textural properties of meat emulsion under various formulations. As an initial marker of functionality, protein solubility, water absorption, emulsifying capacity, and gel formation ability of house cricket flour were determined at pH (2 to 10) and NaCl concentrations (0 to 2.10 M). Control emulsion was formulated with 60% lean pork, 20% back fat, and 20% ice. Six treatment emulsions were prepared with replacement of lean pork and/or back fat portions with spray-dried house cricket flour at 5% and 10% levels, based on a total sample weight. The protein solubility of house cricket flour (67 g protein/100 g) was significantly altered depending upon pH (P < 0.0001) and NaCl concentration (P = 0.0421). Similar water absorption capacity, emulsifying capacity, and gel formation ability of house cricket flour were found between 0 and 2.10 M NaCl concentration (P > 0.05). The replacement of lean meat/fat portion with house cricket flour within 10% level could fortify protein and some micronutrients (phosphorus, potassium, and magnesium) in meat emulsion, without negative impacts on cooking yield and textural properties. Our results suggest that house cricket flour can be used as an effective nonmeat functional ingredient to manufacture emulsified meat products. To better utilize house cricket flour as a food ingredient in wide application, understanding its technological properties in various pH, and ionic strength conditions is a pivotal step. Protein solubility of house cricket flour would be considerably affected by the varying pH and NaCl concentrations of applied conventional foods. In the case of meat emulsion, within 10% lean meat and/or fat portions could be successfully substituted with house cricket flour without detectable adverse impacts on technological properties associated with cooking yield and instrumental analysis of texture. Thus, our findings suggest that house cricket flour possess the necessary physical properties to be used as an alternative nonmeat ingredient for incorporation within emulsified meat products, which could be further explored in subsequent sensory-based studies. © 2017 Institute of Food Technologists®.

Comparison of the compact dry TC method with the standard method ISO 21149:2006 for determining aerobic colony counts in cosmetic emulsion.

PubMed

De Vaugelade, S; Aime, M; Farcette, N; Maurel, E; Lacour, T; Thomas, C; Bouchonnet, S; Pirnay, S

2017-02-01

Compact Dry TC, a rapid method kit for determining aerobic colony counts, has been developed by Nissui Pharmaceutical Co. for food application. These plates are pre-sterilized and contain culture medium, a cold-soluble gelling agent and a colour redox indicator for rapid enumeration. In this study, the alternative method is compared with the standard method ISO 21149:2006 - Cosmetic - Microbiology - Enumeration and detection of aerobic mesophilic bacteria, for cosmetic emulsions application. An oil-in-water (o/w) cosmetic emulsion was contaminated with a pool of bacterial strains (Escherichia coli ATCC 8739, Staphylococcus aureus ATCC 6538 and Pseudomonas aeruginosa ATCC 9027). One millilitre of samples was spread on agar as described in ISO 21149. The colonies were enumerated after 3 days of incubation. At the same time, 1.2 mL samples were spread on Compact Dry TC kits. The kit was incubated at 35°C ± 1°C for 48 h, and the colonies were enumerated. Accuracy determination was carried out using six replicates at four levels of concentrations (10, 50, 100 and 250 CFU mL -1 ). The repeatability study was carried out using 12 replicates at four levels of concentrations (10, 50, 100 and 250 CFU mL -1 ). Variations relative to the analyst and to the batch of emulsion have been investigated. The linear correlation coefficients of Compact Dry TC Kit enumeration with standard method ISO 21149:2006 was 0.9999. In comparison study, no apparent differences were noted between the Compact Dry TC kit and the reference method ISO 21149, for the detection level of aerobic microorganisms. Relative accuracy, repeatability and intermediate precision studies were acceptable. In the repeatability study, the Shapiro-Wilk test has confirmed the normally distribution of the twelve assays. No significant variations in Compact Dry TC count results were observed with different analysts and different batches of emulsion. The results showed that the two compared methods 'Compact Dry TC' vs. 'conventional pour plate' performed equally well. Demonstration was achieved that the Compact Dry TC method may constitute a useful alternative tool for rapid enumeration of aerobic mesophilic bacteria in cosmetic emulsions. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Lingonberry (Vaccinium vitis-idaea) and European cranberry (Vaccinium microcarpon) proanthocyanidins: isolation, identification, and bioactivities.

PubMed

Kylli, Petri; Nohynek, Liisa; Puupponen-Pimiä, Riitta; Westerlund-Wikström, Benita; Leppänen, Tiina; Welling, Jukka; Moilanen, Eeva; Heinonen, Marina

2011-04-13

European, small-fruited cranberries (Vaccinium microcarpon) and lingonberries (Vaccinium vitis-idaea) were characterized for their phenolic compounds and tested for antioxidant, antimicrobial, antiadhesive, and antiinflammatory effects. The main phenolic compounds in both lingonberries and cranberries were proanthocyanidins comprising 63-71% of the total phenolic content, but anthocyanins, hydroxycinnamic acids, hydroxybenzoic acids, and flavonols were also found. Proanthocyanidins are polymeric phenolic compounds consisting mainly of catechin, epicatechin, gallocatechin, and epigallocatechin units. In the present study, proanthocyanidins were divided into three groups: dimers and trimers, oligomers (mDP 4-10), and polymers (mDP > 10). Catechin, epicatechin, A-type dimers and trimers were found to be the terminal units of isolated proanthocyanidin fractions. Inhibitions of lipid oxidation in liposomes were over 70% and in emulsions over 85%, and in most cases the oligomeric or polymeric fraction was the most effective. Polymeric proanthocyanidin extracts of lingonberries and cranberries were strongly antimicrobial against Staphylococcus aureus, whereas they had no effect on other bacterial strains such as Salmonella enterica sv. Typhimurium, Lactobacillus rhamnosus and Escherichia coli. Polymeric fraction of cranberries and oligomeric fractions of both lingonberries and cranberries showed an inhibitory effect on hemagglutination of E. coli, which expresses the M hemagglutin. Cranberry phenolic extract inhibited LPS-induced NO production in a dose-dependent manner, but it had no major effect on iNOS of COX-2 expression. At a concentration of 100 μg/mL cranberry phenolic extract inhibited LPS-induced IL-6, IL-1β and TNF-α production. Lingonberry phenolics had no significant effect on IL-1β production but inhibited IL-6 and TNF-α production at a concentration of 100 μg/mL similarly to cranberry phenolic extract. In conclusion the phenolics, notably proanthocyanidins (oligomers and polymers), in both lingonberries and cranberries exert multiple bioactivities that may be exploited in food development.

Physico-chemical effects of supercritical carbon dioxide post polymerization treatment on HCl-doped polyaniline prepared via oxidative chemical polymerization

NASA Astrophysics Data System (ADS)

Fernando, J. G.; Vequizo, R. M.; Odarve, M. K. G.; Sambo, B. R. B.; Alguno, A. C.; Malaluan, R. M.; Candidato, R. T., Jr.; Gambe, J. E.; Jabian, M.; Paylaga, G. J.; Bagsican, F. R. G.; Miyata, H.

2015-06-01

Polyanilinefilms doped with varying HClconcentrations (0.2 M, 0.6 M and 1.0 M) were synthesized on glass substrates via oxidative polymerization of aniline. The films were treated with supercritical carbon dioxide (SC-CO2) at 30 MPa and 40°C for 30 minutes. Their structural, optical and morphological properties were studied and compared to conventionally prepared polyanilinefilms using FTIR analysis, UVVisspectroscopy and scanning electron microscopy. It was observed that supercritical carbon dioxide (SC-CO2) could interact with PANI films that consequently altered the bandgapsand changed the film thickness. SC-CO2 treatment also increased the oxidation level of polyanilinefilms and modified the morphology of polyanilinefilm doped with 1M HCl.

Rapid energy-efficient manufacturing of polymers and composites via frontal polymerization.

PubMed

Robertson, Ian D; Yourdkhani, Mostafa; Centellas, Polette J; Aw, Jia En; Ivanoff, Douglas G; Goli, Elyas; Lloyd, Evan M; Dean, Leon M; Sottos, Nancy R; Geubelle, Philippe H; Moore, Jeffrey S; White, Scott R

2018-05-01

Thermoset polymers and composite materials are integral to today's aerospace, automotive, marine and energy industries and will be vital to the next generation of lightweight, energy-efficient structures in these enterprises, owing to their excellent specific stiffness and strength, thermal stability and chemical resistance 1-5 . The manufacture of high-performance thermoset components requires the monomer to be cured at high temperatures (around 180 °C) for several hours, under a combined external pressure and internal vacuum 6 . Curing is generally accomplished using large autoclaves or ovens that scale in size with the component. Hence this traditional curing approach is slow, requires a large amount of energy and involves substantial capital investment 6,7 . Frontal polymerization is a promising alternative curing strategy, in which a self-propagating exothermic reaction wave transforms liquid monomers to fully cured polymers. We report here the frontal polymerization of a high-performance thermoset polymer that allows the rapid fabrication of parts with microscale features, three-dimensional printed structures and carbon-fibre-reinforced polymer composites. Precise control of the polymerization kinetics at both ambient and elevated temperatures allows stable monomer solutions to transform into fully cured polymers within seconds, reducing energy requirements and cure times by several orders of magnitude compared with conventional oven or autoclave curing approaches. The resulting polymer and composite parts possess similar mechanical properties to those cured conventionally. This curing strategy greatly improves the efficiency of manufacturing of high-performance polymers and composites, and is widely applicable to many industries.

The effects of emulsifying agents on disposition of lipid-soluble drugs included in fat emulsion.

PubMed

Suzuki, Yasuyuki; Masumitsu, Yasushi; Okudaira, Kazuho; Hayashi, Masahiro

2004-02-01

The uses for drug delivery systems of two soybean oil fat emulsions prepared with an emulsifying agent, phosphatidyl choline (PC) or Pluronic F-127 (PLU), were examined comparatively in vivo and in vitro. In the presence of lipoprotein lipase (LPL) in vitro, the mean particle size of the PLU emulsion changed less than that of the PC emulsion. The production of non-esterified fatty acid (NEFA) from the PLU emulsion in the presence of LPL was smaller than that from the PC emulsion. These in vitro results indicate that the PLU emulsion is more stable than the PC emulsion. Plasma NEFA concentration following intravenous administration of the emulsions decreased with time for the PC emulsion, but was kept lower and constant for the PLU emulsion, supporting the in vitro stability data. The order of plasma cyclosporine A (CsA) concentration following intravenous administration in the above two emulsions and the mixed solution of polyethylene glycol 400 (PEG) and dimethylamide (DMA) in rats was PLU emulsion>PC emulsion>PEG/DMA solution. The plasma concentration was maintained higher and tissue distribution lower for the PLU emulsion than for other formulations. The uptake of oil violet (OV) into the rat parenchymal cells from the PLU emulsion was approximately half that from the PC emulsion, but the uptake into the Kupffer cells was almost equal in both emulsions. In conclusion, these emulsifying agents can control plasma elimination and tissue distribution of lipophilic drugs included in the emulsion. The use of the emulsion formulation makes it possible to avoid side effects through the reduction of drug uptake into non-targeted tissues.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, N.S.K.

In aqueous lysine-sucrose model systems, the effects of reaction time, pH and molar ratio were studied on the formation of non-enzymatic browning reaction (NBR) products. The extent of sucrose hydrolysis was measured and the antioxidant effect of NBR products on linoleic acid emulsions was examined. Nuclear magnetic resonance (NMR) spectra were obtained at various stages of browning. Sucrose produced NMR produces with lysine in an aqueous system at 100/sup 0/C. The C-13 NMR spectra indicated that the NBR started when sucrose and lysine were dissolved in water. The C-13 NMR spectra also showed that heating did not have an effectmore » on the gross composition of polymeric species. The absorbance at 480 nm of 0.75 M lysine-sucrose solution heated up to 6 hours increased with reaction times. The pH values of heated lysine-sucrose solution gradually decreased with reaction time. When 0.75 M sucrose or lysine solution was heated separately up to 6 hours, there were no changes in absorbance in pH. In the pH range of 3.52-6.35, higher absorbance was obtained from heated lysine-sucrose solution at acidic pH levels than at neutral pH levels. As the concentration of lysine and sucrose solution was increased, the absorbance increased. At longer reaction times or acidic pH levels, enhanced hydrolysis of sucrose to reducing sugars resulted in more NBR products. NBR products obtained at a longer reaction time, an acidic pH, and higher concentration of reactants showed a darker brown color and were effective in preventing the formation of peroxides. The oxygen uptake of linoleic acid emulsion having NBR products was smaller than that of linoleic acid emulsion without NBR products. Based on these results, it was concluded that sucrose may act as an antioxidant in processed foods containing both amino acids and lipids.« less

Water reclamation from emulsified oily wastewater via effective forward osmosis hollow fiber membranes under the PRO mode.

PubMed

Han, Gang; de Wit, Jos S; Chung, Tai-Shung

2015-09-15

By using a novel hydrophilic cellulose acetate butyrate (CAB) as the membrane material for the hollow fiber substrate and modifying its outer surface by polydopamine (PDA) coating and inner surface by interfacial polymerization, we have demonstrated that the thin-film composite (TFC) membranes can be effectively used for sustainable water reclamation from emulsified oil/water streams via forward osmosis (FO) under the pressure retarded osmosis (PRO) mode. The newly developed TFC-FO hollow fiber membrane shows characteristics of high water flux, outstanding salt and oil rejection, and low fouling propensity. Under the PRO mode, the newly developed TFC-FO membrane exhibits a water flux of 37.1 L m(-2) h(-1) with an oil rejection of 99.9% using a 2000 ppm soybean oil/water emulsion as the feed and 1 M NaCl as the draw solution. Remarkable anti-fouling behaviors have also been observed. Under the PRO mode, the water flux decline is only 10% of the initial value even after a 12 h test for oil/water separation. The water flux of the fouled membrane can be effectively restored to 97% of the original value by water rinses on the fiber outer surface without using any chemicals. Furthermore, the flux declines are only 25% and 52% when the water recovery of a 2000 ppm soybean oil/water emulsion and a 2000 ppm petroleum oil/water emulsion containing 0.04 M NaCl reaches 82%, respectively. This study may not only provide insightful guidelines for the fabrication of effective TFC-FO membranes with high performance and low fouling behaviors for oily wastewater under the PRO mode but also add an alternative perspective to the design of new materials for water purification purposes. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nano-network with dual temperature and pH responsiveness based on copolymers of 2-hydroxyethyl methacrylate with 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]-undecane

NASA Astrophysics Data System (ADS)

Chiriac, Aurica P.; Nita, Loredana E.; Nistor, Manuela T.

2011-12-01

This study refers to the synthesis of a nano-network with dual temperature and pH responsiveness based on the 2-hydroxyethyl methacrylate (HEMA) copolymers with a comonomer with spiroacetal moiety and crosslinking capacity, namely 3,9-divinyl-2,4,8,10-tetraoxaspiro[5.5]-undecane (U). The copolymers were synthesized by radical emulsion polymerization, using 4,4'-azobis(cyanopentanoic acid) as initiator, in the presence of sodium lauryl sulfate as tensioactive agent and poly(vinyl alcohol) as protective colloid. Three copolymer variants were taken into study resulted from the different ratio between the comonomers (HEMA/U), which was about 98/2, 95/5, and 90/10, respectively. The copolymers were characterized by FTIR and thermal analysis. The copolymers sensitivity was evidenced by studying the evolution of the hydrodynamic radius and zeta potential of the polymeric particles as a function of pH. Thus, the particles size increases with the comonomer amount, from 193 nm in case of the homopolymer up to 253 nm for the copolymer with maximum content of the comonomer (10%). The increase of the particle hydrodynamic radius with the growth of temperature was also put into evidence.

Synthesis and evaluation on pH- and temperature-responsive chitosan-p(MAA-co-NIPAM) hydrogels.

PubMed

Rasib, S Z M; Ahmad, Z; Khan, A; Akil, H M; Othman, M B H; Hamid, Z A A; Ullah, F

2018-03-01

In this study, chitosan-poly(methacrylic acid-co-N-isopropylacrylamide) [chitosan-p(MAA-co-NIPAM)] hydrogels were synthesized by emulsion polymerization. In order to be used as a carrier for drug delivery systems, the hydrogels had to be biocompatible, biodegradable and multi-responsive. The polymerization was performed by copolymerize MAA and NIPAM with chitosan polymer to produce a chitosan-based hydrogel. Due to instability during synthesis and complexity of components to produce the hydrogel, further study at different times of reaction is important to observe the synthesis process, the effect of end product on swelling behaviour and the most important is to find the best way to control the hydrogel synthesis in order to have an optimal swelling behaviour for drug release application. Studied by using Fourier transform infra-red (FTIR) spectroscopy found that, the synthesized was successfully produced stable chitosan-based hydrogel with PNIPAM continuously covered the outer surface of hydrogel which influenced much on the stability during synthesis. The chitosan and PMAA increased the zeta potential of the hydrogel and the chitosan capable to control shrinkage above human body temperature. The chitosan-p(MAA-co-NIPAM) hydrogels also responses to pH and temperature thus improved the ability to performance as a drug carrier. Copyright © 2017 Elsevier B.V. All rights reserved.

Fluorescent Polymer Nanoparticles Based on Dyes: Seeking Brighter Tools for Bioimaging

PubMed Central

Reisch, Andreas; Klymchenko, Andrey S.

2017-01-01

Speed, resolution and sensitivity of today's fluorescence bioimaging can be drastically improved by fluorescent nanoparticles (NPs) that are many-fold brighter than organic dyes and fluorescent proteins. While the field is currently dominated by inorganic NPs, notably quantum dots (QDs), fluorescent polymer NPs encapsulating large quantities of dyes (dye-loaded NPs) have emerged recently as attractive alternative. These new nanomaterials, inspired from the fields of polymeric drug delivery vehicles and advanced fluorophores, can combine superior brightness with biodegradability and low toxicity. Here, we describe the strategies for synthesis of dye-loaded polymer NPs by emulsion polymerization and assembly of pre-formed polymers. Superior brightness requires strong dye loading without aggregation caused quenching (ACQ). Only recently several strategies of dye design were proposed to overcome ACQ in polymer NPs: aggregation induced emission (AIE), dye modification with bulky side groups and use of bulky hydrophobic counterions. The resulting NPs now surpass the brightness of QDs by ~10-fold for comparable size and start reaching the level of the brightest conjugated polymer NPs. Other properties, notably photostability, color, blinking as well as particle size and surface chemistry are also systematically analyzed. Finally, major and emerging applications of dye-loaded NPs for in vitro and in vivo imaging are reviewed. PMID:26901678

Convection-enhanced delivery and in vivo imaging of polymeric nanoparticles for the treatment of malignant glioma.

PubMed

Bernal, Giovanna M; LaRiviere, Michael J; Mansour, Nassir; Pytel, Peter; Cahill, Kirk E; Voce, David J; Kang, Shijun; Spretz, Ruben; Welp, Ulrich; Noriega, Sandra E; Nunez, Luis; Larsen, Gustavo F; Weichselbaum, Ralph R; Yamini, Bakhtiar

2014-01-01

A major obstacle to the management of malignant glioma is the inability to effectively deliver therapeutic agent to the tumor. In this study, we describe a polymeric nanoparticle vector that not only delivers viable therapeutic, but can also be tracked in vivo using MRI. Nanoparticles, produced by a non-emulsion technique, were fabricated to carry iron oxide within the shell and the chemotherapeutic agent, temozolomide (TMZ), as the payload. Nanoparticle properties were characterized and subsequently their endocytosis-mediated uptake by glioma cells was demonstrated. Convection-enhanced delivery (CED) can disperse nanoparticles through the rodent brain and their distribution is accurately visualized by MRI. Infusion of nanoparticles does not result in observable animal toxicity relative to control. CED of TMZ-bearing nanoparticles prolongs the survival of animals with intracranial xenografts compared to control. In conclusion, the described nanoparticle vector represents a unique multifunctional platform that can be used for image-guided treatment of malignant glioma. GBM remains one of the most notoriously treatment-unresponsive cancer types. In this study, a multifunctional nanoparticle-based temozolomide delivery system was demonstrated to possess enhanced treatment efficacy in a rodent xenograft GBM model, with the added benefit of MRI-based tracking via the incorporation of iron oxide as a T2* contrast material in the nanoparticles. © 2014.

Synthesis of highly monodisperse particles composed of a magnetic core and fluorescent shell.

PubMed

Nagao, Daisuke; Yokoyama, Mikio; Yamauchi, Noriko; Matsumoto, Hideki; Kobayashi, Yoshio; Konno, Mikio

2008-09-02

Highly monodisperse particles composed of a magnetic silica core and fluorescent polymer shell were synthesized with a combined technique of heterocoagulation and soap-free emulsion polymerization. Prior to heterocoagulation, monodisperse, submicrometer-sized silica particles were prepared with the Stober method, and magnetic nanoparticles were prepared with a modified Massart method in which a cationic silane coupling agent of N-trimethoxysilylpropyl- N, N, N-trimethylammonium chloride was added just after coprecipitation of Fe (2+) and Fe (3+). The silica particles with negative surface potential were heterocoagulated with the magnetic nanoparticles with positive surface potential. The magnetic silica particles obtained with the heterocoagulation were treated with sodium silicate to modify their surfaces with silica. In the formation of a fluorescent polymer shell onto the silica-coated magnetic silica cores, an amphoteric initiator of 2,2'-azobis[ N-(2-carboxyethyl)-2-2-methylpropionamidine] (VA-057) was used to control the colloidal stability of the magnetic cores during the polymer coating. The polymerization of St in the presence of a hydrophobic fluorophore of pyrene could coat the cores with fluorescent polymer shells, resulting in monodisperse particles with a magnetic silica core and fluorescent polymer shell. Measurements of zeta potential for the composite particles in different pH values indicated that the composite particles had an amphoteric property originating from VA-057 initiator.

ATRP-based synthesis and characterization of light-responsive coatings for transdermal delivery systems

PubMed Central

Pauly, Anja C; Schöller, Katrin; Baumann, Lukas; Rossi, René M; Dustmann, Kathrin; Ziener, Ulrich; de Courten, Damien; Wolf, Martin; Boesel, Luciano F; Scherer, Lukas J

2015-01-01

The grafting of poly(hydroxyethylmethacrylate) on polymeric porous membranes via atom transfer radical polymerization (ATRP) and subsequent modification with a photo-responsive spiropyran derivative is described. This method leads to photo-responsive membranes with desirable properties such as light-controlled permeability changes, exceptional photo-stability and repeatability of the photo-responsive switching. Conventional track etched polyester membranes were first treated with plasma polymer coating introducing anchoring groups, which allowed the attachment of ATRP-initiator molecules on the membrane surface. Surface initiated ARGET–ATRP of hydroxyethylmethacrylate (where ARGET stands for activator regenerated by electron transfer) leads to a membrane covered with a polymer layer, whereas the controlled polymerization procedure allows good control over the thickness of the polymer layer in respect to the polymerization conditions. Therefore, the final permeability of the membranes could be tailored by choice of pore diameter of the initial membranes, applied monomer concentration or polymerization time. Moreover a remarkable switch in permeability (more than 1000%) upon irradiation with UV-light could be achieved. These properties enable possible applications in the field of transdermal drug delivery, filtration, or sensing. PMID:27877791

ATRP-based synthesis and characterization of light-responsive coatings for transdermal delivery systems

NASA Astrophysics Data System (ADS)

Pauly, Anja C.; Schöller, Katrin; Baumann, Lukas; Rossi, René M.; Dustmann, Kathrin; Ziener, Ulrich; de Courten, Damien; Wolf, Martin; Boesel, Luciano F.; Scherer, Lukas J.

2015-06-01

The grafting of poly(hydroxyethylmethacrylate) on polymeric porous membranes via atom transfer radical polymerization (ATRP) and subsequent modification with a photo-responsive spiropyran derivative is described. This method leads to photo-responsive membranes with desirable properties such as light-controlled permeability changes, exceptional photo-stability and repeatability of the photo-responsive switching. Conventional track etched polyester membranes were first treated with plasma polymer coating introducing anchoring groups, which allowed the attachment of ATRP-initiator molecules on the membrane surface. Surface initiated ARGET-ATRP of hydroxyethylmethacrylate (where ARGET stands for activator regenerated by electron transfer) leads to a membrane covered with a polymer layer, whereas the controlled polymerization procedure allows good control over the thickness of the polymer layer in respect to the polymerization conditions. Therefore, the final permeability of the membranes could be tailored by choice of pore diameter of the initial membranes, applied monomer concentration or polymerization time. Moreover a remarkable switch in permeability (more than 1000%) upon irradiation with UV-light could be achieved. These properties enable possible applications in the field of transdermal drug delivery, filtration, or sensing.

The fabrication of small molecule organic light-emitting diode pixels by laser-induced forward transfer

NASA Astrophysics Data System (ADS)

Shaw-Stewart, J. R. H.; Mattle, T.; Lippert, T. K.; Nagel, M.; Nüesch, F. A.; Wokaun, A.

2013-01-01

Laser-induced forward transfer (LIFT) is a versatile organic light-emitting diode (OLED) pixel deposition process, but has hitherto been applied exclusively to polymeric materials. Here, a modified LIFT process has been used to fabricate small molecule Alq3 organic light-emitting diodes (SMOLEDs). Small molecule thin films are considerably more mechanically brittle than polymeric thin films, which posed significant challenges for LIFT of these materials. The LIFT process presented here uses a polymeric dynamic release layer, a reduced environmental pressure, and a well-defined receiver-donor gap. The Alq3 pixels demonstrate good morphology and functionality, even when compared to conventionally fabricated OLEDs. The Alq3 SMOLED pixel performances show a significant amount of fluence dependence, not observed with polymerical OLED pixels made in previous studies. A layer of tetrabutyl ammonium hydroxide has been deposited on top of the aluminium cathode, as part of the donor substrate, to improve electron injection to the Alq3, by over 600%. These results demonstrate that this variant of LIFT is applicable for the deposition of functional small molecule OLEDs as well as polymeric OLEDs.

The research about microscopic structure of emulsion membrane in O/W emulsion by NMR and its influence to emulsion stability.

PubMed

Xie, Yiqiao; Chen, Jisheng; Zhang, Shu; Fan, Kaiyan; Chen, Gang; Zhuang, Zerong; Zeng, Mingying; Chen, De; Lu, Longgui; Yang, Linlin; Yang, Fan

2016-03-16

This paper discussed the influence of microstructure of emulsion membrane on O/W emulsion stability. O/W emulsions were emulsified with equal dosage of egg yolk lecithin and increasing dosage of co-emulsifier (oleic acid or HS15). The average particle size and centrifugal stability constant of emulsion, as well as interfacial tension between oil and water phase were determined. The microstructure of emulsion membrane had been studied by (1)H/(13)C NMR, meanwhile the emulsion droplets were visually presented with TEM and IFM. With increasing dosage of co-emulsifier, emulsions showed two stable states, under which the signal intensity of characteristic group (orient to lipophilic core) of egg yolk lecithin disappeared in NMR of emulsions, but that (orient to aqueous phase) of co-emulsifiers only had some reduction at the second stable state. At the two stable states, the emulsion membranes were neater in TEM and emulsion droplets were rounder in IFM. Furthermore, the average particle size of emulsions at the second stable state was bigger than that at the first stable state. Egg yolk lecithin and co-emulsifier respectively arranged into monolayer and bilayer emulsion membrane at the two stable states. The microstructure of emulsion membrane was related to the stability of emulsion. Copyright © 2016 Elsevier B.V. All rights reserved.

The effect of photopolymerization on the degree of conversion, polymerization kinetic, biaxial flexure strength, and modulus of self-adhesive resin cements.

PubMed

Aguiar, Thaiane R; de Oliveira, Michele; Arrais, César A G; Ambrosano, Glaucia M B; Rueggeberg, Frederick; Giannini, Marcelo

2015-02-01

Understanding the effect of the degree of conversion on the mechanical properties of auto- and dual-polymerizing self-adhesive resin cements leads to a better estimation of their performance in different clinical scenarios. The purpose of this study was to evaluate the effect of photopolymerization on the degree of conversion (DC) and polymerization kinetic of 4 dual-polymerized resin cements, 20 minutes after mixing, and its effects on the mechanical properties (biaxial flexural strength [FS] and modulus [FM]) after short-term aging. Conventional (RelyX ARC and Clearfil Esthetic Cement) and self-adhesive resin cements (RelyX Unicem and Clearfil SA Cement) were applied to a Fourier infrared spectrometer to assess the DC (n=5) under the following 3 polymerization conditions: direct light exposure (dual-polymerizing mode), exposure through the prepolymerized disk, or autopolymerizing. The polymerization kinetic was recorded for 20 minutes. Then, disk-shaped specimens (n=11) were prepared to evaluate the effect of polymerization on the FS and FM in both extreme polymerization conditions (dual-polymerizing or autopolymerizing). Data were statistically analyzed by 2-way repeated measure ANOVA (DC) and by 2-way ANOVA (FS and FM), followed by the Tukey-Kramer post hoc test (α=.05). Autopolymerizing groups exhibited reduced DC means, whereas intermediate values were observed when resin cements were polymerized through the disk. All groups exhibited higher DC at the end of 20 minutes. The polymerization kinetic revealed a rising curve, and materials, when directly photopolymerized, reached a plateau immediately after light exposure. Regarding the flexural biaxial testing, most of the resin cements were affected by polymerization mode and differences among groups were product dependent. The resin cements achieved immediate higher DC and mechanical properties when photopolymerized. The total absence of photoactivation may still impair their mechanical properties even after short-term aging. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

The influence of the emulsion composition on the wettability of the emulsion

NASA Astrophysics Data System (ADS)

Liu, Yan Jun; Shao, Jian Nan; Lei Liu, Peng

2018-03-01

In order to explore the influence of the emulsion composition on the wettability of the emulsion, using lauric acid polyoxyethylene esters (LAE) and polyethylene oleic acid diester (DQA) as the emulsifier and oleic acid ester (QA) as the smoothing agent, the spinning oil emulsion system with the content of smoothing agent above 30% was prepared. The results show that: with the increase of emulsion concentration, the surface tension of emulsion, the contact Angle of emulsion on the surface of the polypropylene fiber and the wetting time of canvas in emulsion all decreases. At the same time,the emulsion has critical micelle concentration, when the concentration is less than CMC, the surface tension of emulsion, the contact Angle of emulsion on the surface of the polypropylene fiber and the wetting time of canvas in the emulsion decreases rapidly with the increase of the emulsion concentration, while it’s more than this concentration, the influence of emulsion concentration on the three kinds of nature is smaller. Besides, the increase of the mass fraction of the smoothing agent and the increase of the compound emulsifier HLB will result in worse wettability.

Comparison of Enzymatic and Ultrasonic Extraction of Albumin from Defatted Pumpkin (Cucurbita pepo)
Seed Powder

PubMed Central

Tu, Gia Loi; Bui, Thi Hoang Nga; Tran, Thi Thu Tra; Ton, Nu Minh Nguyet

2015-01-01

Summary In this study, ultrasound- and enzyme-assisted extractions of albumin (water-soluble protein group) from defatted pumpkin (Cucurbita pepo) seed powder were compared. Both advanced extraction techniques strongly increased the albumin yield in comparison with conventional extraction. The extraction rate was two times faster in the ultrasonic extraction than in the enzymatic extraction. However, the maximum albumin yield was 16% higher when using enzymatic extraction. Functional properties of the pumpkin seed albumin concentrates obtained using the enzymatic, ultrasonic and conventional methods were then evaluated. Use of hydrolase for degradation of cell wall of the plant material did not change the functional properties of the albumin concentrate in comparison with the conventional extraction. The ultrasonic extraction enhanced water-holding, oil-holding and emulsifying capacities of the pumpkin seed albumin concentrate, but slightly reduced the foaming capacity, and emulsion and foam stability. PMID:27904383

Comparison of Enzymatic and Ultrasonic Extraction of Albumin from Defatted Pumpkin (Cucurbita pepo)
Seed Powder.

PubMed

Tu, Gia Loi; Bui, Thi Hoang Nga; Tran, Thi Thu Tra; Ton, Nu Minh Nguyet; Man Le, Van Viet

2015-12-01

In this study, ultrasound- and enzyme-assisted extractions of albumin (water-soluble protein group) from defatted pumpkin ( Cucurbita pepo ) seed powder were compared. Both advanced extraction techniques strongly increased the albumin yield in comparison with conventional extraction. The extraction rate was two times faster in the ultrasonic extraction than in the enzymatic extraction. However, the maximum albumin yield was 16% higher when using enzymatic extraction. Functional properties of the pumpkin seed albumin concentrates obtained using the enzymatic, ultrasonic and conventional methods were then evaluated. Use of hydrolase for degradation of cell wall of the plant material did not change the functional properties of the albumin concentrate in comparison with the conventional extraction. The ultrasonic extraction enhanced water-holding, oil-holding and emulsifying capacities of the pumpkin seed albumin concentrate, but slightly reduced the foaming capacity, and emulsion and foam stability.

One-Step Generation of Multifunctional Polyelectrolyte Microcapsules via Nanoscale Interfacial Complexation in Emulsion (NICE)

DOE PAGES

Kim, Miju; Yeo, Seon Ju; Highley, Christopher B.; ...

2015-07-14

Polyelectrolyte microcapsules represent versatile stimuli-responsive structures that enable the encapsulation, protection, and release of active agents. Their conventional preparation methods, however, tend to be time-consuming, yield low encapsulation efficiency, and seldom allow for the dual incorporation of hydrophilic and hydrophobic materials, limiting their widespread utilization. In this work, we present a method to fabricate stimuli-responsive polyelectrolyte microcapsules in one step based on nanoscale interfacial complexation in emulsions (NICE) followed by spontaneous droplet hatching. NICE microcapsules can incorporate both hydrophilic and hydrophobic materials and also can be induced to trigger the release of encapsulated materials by changes in the solution pHmore » or ionic strength. We also show that NICE microcapsules can be functionalized with nanomaterials to exhibit useful functionality, such as response to a magnetic field and disassembly in response to light. NICE represents a potentially transformative method to prepare multifunctional nanoengineered polyelectrolyte microcapsules for various applications such as drug delivery and cell mimicry.« less

Solid lipid nanoparticles as carrier for sunscreens: in vitro release and in vivo skin penetration.

PubMed

Wissing, S A; Müller, R H

2002-06-17

The aim of this study was the comparison of two different formulations (solid lipid nanoparticles (SLN) and conventional o/w emulsion) as carrier systems for the molecular sunscreen oxybenzone. The influence of the carrier on the rate of release was studied in vitro with a membrane-free model. The release rate could be decreased by up to 50% with the SLN formulation. Further in vitro measurements with static Franz diffusion cells were performed. In vivo, penetration of oxybenzone into stratum corneum on the forearm was investigated by the tape stripping method. It was shown that the rate of release is strongly dependent upon the formulation and could be decreased by 30-60% in SLN formulations. In all test models, oxybenzone was released and penetrated into human skin more quickly and to a greater extent from the emulsions. The rate of release also depends upon the total concentration of oxybenzone in the formulation. In vitro-in vivo correlations could be made qualitatively.

One-Step Generation of Multifunctional Polyelectrolyte Microcapsules via Nanoscale Interfacial Complexation in Emulsion (NICE).

PubMed

Kim, Miju; Yeo, Seon Ju; Highley, Christopher B; Burdick, Jason A; Yoo, Pil J; Doh, Junsang; Lee, Daeyeon

2015-08-25

Polyelectrolyte microcapsules represent versatile stimuli-responsive structures that enable the encapsulation, protection, and release of active agents. Their conventional preparation methods, however, tend to be time-consuming, yield low encapsulation efficiency, and seldom allow for the dual incorporation of hydrophilic and hydrophobic materials, limiting their widespread utilization. In this work, we present a method to fabricate stimuli-responsive polyelectrolyte microcapsules in one step based on nanoscale interfacial complexation in emulsions (NICE) followed by spontaneous droplet hatching. NICE microcapsules can incorporate both hydrophilic and hydrophobic materials and also can be induced to trigger the release of encapsulated materials by changes in the solution pH or ionic strength. We also show that NICE microcapsules can be functionalized with nanomaterials to exhibit useful functionality, such as response to a magnetic field and disassembly in response to light. NICE represents a potentially transformative method to prepare multifunctional nanoengineered polyelectrolyte microcapsules for various applications such as drug delivery and cell mimicry.

One-Step Generation of Multifunctional Polyelectrolyte Microcapsules via Nanoscale Interfacial Complexation in Emulsion (NICE)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Miju; Yeo, Seon Ju; Highley, Christopher B.

Polyelectrolyte microcapsules represent versatile stimuli-responsive structures that enable the encapsulation, protection, and release of active agents. Their conventional preparation methods, however, tend to be time-consuming, yield low encapsulation efficiency, and seldom allow for the dual incorporation of hydrophilic and hydrophobic materials, limiting their widespread utilization. In this work, we present a method to fabricate stimuli-responsive polyelectrolyte microcapsules in one step based on nanoscale interfacial complexation in emulsions (NICE) followed by spontaneous droplet hatching. NICE microcapsules can incorporate both hydrophilic and hydrophobic materials and also can be induced to trigger the release of encapsulated materials by changes in the solution pHmore » or ionic strength. We also show that NICE microcapsules can be functionalized with nanomaterials to exhibit useful functionality, such as response to a magnetic field and disassembly in response to light. NICE represents a potentially transformative method to prepare multifunctional nanoengineered polyelectrolyte microcapsules for various applications such as drug delivery and cell mimicry.« less

Holographic Optical Elements Recorded in Silver Halide Sensitized Gelatin Emulsions. Part I. Transmission Holographic Optical Elements

NASA Astrophysics Data System (ADS)

Kim, Jong Man; Choi, Byung So; Kim, Sun Il; Kim, Jong Min; Bjelkhagen, Hans I.; Phillips, Nicholas J.

2001-02-01

Silver halide sensitized gelatin (SHSG) holograms are similar to holograms recorded in dichromated gelatin (DCG), the main recording material for holographic optical elements (HOE s). The drawback of DCG is its low sensitivity and limited spectral response. Silver halide materials can be processed in such a way that the final hologram will have properties like a DCG hologram. Recently this technique has become more interesting since the introduction of new ultra-high-resolution silver halide emulsions. An optimized processing technique for transmission HOE s recorded in these materials is introduced. Diffraction efficiencies over 90% can be obtained for transmissive diffraction gratings. Understanding the importance of the selective hardening process has made it possible to obtain results similar to conventional DCG processing. The main advantage of the SHSG process is that high-sensitivity recording can be performed with laser wavelengths anywhere within the visible spectrum. This simplifies the manufacturing of high-quality, large-format HOE s.

Fluorescent holograms with albumin-acrylamide

NASA Astrophysics Data System (ADS)

Ordóñez-Padilla, M. J.; Olivares-Pérez, A.; Fuentes-Tapia, I.

2014-02-01

We describe fluorescent holograms were made with photosensitive films of albumin (protein) quail, used as modified matrices. Albumin is mixed with acrylamide and eosin Y. Therefore, prepare a photosensitive emulsion and solid hydrated with the ability to phase transmission holograms and volume (VPH). Eosin Y is a fluorescent agent that acts as a photo-sensitizing dye which stimulates the polymerization of acrylamide. To record the interference pattern produced by two waves superimposed on the modified matrix, we use a He-Cd laser. To reconstruct the diffraction pattern is observed with He- Ne laser, λ = 632.8nm, the material is self-developing properties. Measure the diffraction efficiency of the diffracted orders (η[-1, +1]) as a function of exposure energy. We work with various thicknesses and measure the variation of the refractive index using the coupled wave theory of Kogelnik, the holographic gratings meet Bragg condition.

Introduction to optical methods for characterizing liquid crystals at interfaces.

PubMed

Miller, Daniel S; Carlton, Rebecca J; Mushenheim, Peter C; Abbott, Nicholas L

2013-03-12

This Instructional Review describes methods and underlying principles that can be used to characterize both the orientations assumed spontaneously by liquid crystals (LCs) at interfaces and the strength with which the LCs are held in those orientations (so-called anchoring energies). The application of these methods to several different classes of LC interfaces is described, including solid and aqueous interfaces as well as planar and nonplanar interfaces (such as those that define a LC-in-water emulsion droplet). These methods, which enable fundamental studies of the ordering of LCs at polymeric, chemically functionalized, and biomolecular interfaces, are described in this Instructional Review on a level that can be easily understood by a nonexpert reader such as an undergraduate or graduate student. We focus on optical methods because they are based on instrumentation that is found widely in research and teaching laboratories.

Sequential self-assembly of DNA functionalized droplets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yin; McMullen, Angus; Pontani, Lea-Laetitia

Complex structures and devices, both natural and manmade, are often constructed sequentially. From crystallization to embryogenesis, a nucleus or seed is formed and built upon. Sequential assembly allows for initiation, signaling, and logical programming, which are necessary for making enclosed, hierarchical structures. Though biology relies on such schemes, they have not been available in materials science. We demonstrate programmed sequential self-assembly of DNA functionalized emulsions. The droplets are initially inert because the grafted DNA strands are pre-hybridized in pairs. Active strands on initiator droplets then displace one of the paired strands and thus release its complement, which in turn activatesmore » the next droplet in the sequence, akin to living polymerization. This strategy provides time and logic control during the self-assembly process, and offers a new perspective on the synthesis of materials.« less

CO2-Switchable Membranes Prepared by Immobilization of CO2-Breathing Microgels.

PubMed

Zhang, Qi; Wang, Zhenwu; Lei, Lei; Tang, Jun; Wang, Jianli; Zhu, Shiping

2017-12-20

Herein, we report the development of a novel CO 2 -responsive membrane system through immobilization of CO 2 -responsive microgels into commercially available microfiltration membranes using a method of dynamic adsorption. The microgels, prepared from soap-free emulsion polymerization of CO 2 -responsive monomer 2-(diethylamino)ethyl methacrylate (DEA), can be reversibly expanded and shrunken upon CO 2 /N 2 alternation. When incorporated into the membranes, this switching behavior was preserved and further led to transformation between microfiltration and ultrafiltration membranes, as indicated from the dramatic changes on water flux and BSA rejection results. This CO 2 -regulated performance switching of membranes was caused by the changes of water transportation channel, as revealed from the dynamic water contact angle tests and SEM observation. This work represents a simple yet versatile strategy for making CO 2 -responsive membranes.

Synthesis and chromatographic characterization of dextran-coated zirconia high-performance liquid chromatographic stationary phases.

PubMed

Dunlap, C J; Carr, P W

1996-10-11

Porous zirconia particles made by the oil emulsion (OE) method and the polymerization-induced colloid aggregation (PICA) method have been coated with a small, carboxymethylated (approximately 5%) dextran polymer and crosslinked in place. The parameters of the coating process (dextran concentration, adsorption time and crosslinker concentration) have all been examined and an optimum value for each determined. The coated and uncoated materials were characterized by nitrogen sorptometry and size-exclusion chromatography (SEC) using solutes (polystyrenes and dextrans) of well-defined molecular masses. Nitrogen sorptometry results show that the PICA material has a much lower pore volume and smaller pore diameter than do the OE materials. Despite this, the elution volumes of the SEC probes change very little upon polymer coating the PICA material while the OE material shows a very large change upon coating.

Sequential self-assembly of DNA functionalized droplets

DOE PAGES

Zhang, Yin; McMullen, Angus; Pontani, Lea-Laetitia; ...

2017-06-16

Complex structures and devices, both natural and manmade, are often constructed sequentially. From crystallization to embryogenesis, a nucleus or seed is formed and built upon. Sequential assembly allows for initiation, signaling, and logical programming, which are necessary for making enclosed, hierarchical structures. Though biology relies on such schemes, they have not been available in materials science. We demonstrate programmed sequential self-assembly of DNA functionalized emulsions. The droplets are initially inert because the grafted DNA strands are pre-hybridized in pairs. Active strands on initiator droplets then displace one of the paired strands and thus release its complement, which in turn activatesmore » the next droplet in the sequence, akin to living polymerization. This strategy provides time and logic control during the self-assembly process, and offers a new perspective on the synthesis of materials.« less

Solid Lipid Nanoparticles and Nanostructured Lipid Carriers: Structure, Preparation and Application

PubMed Central

Naseri, Neda; Valizadeh, Hadi; Zakeri-Milani, Parvin

2015-01-01

Lipid nanoparticles (LNPs) have attracted special interest during last few decades. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) are two major types of Lipid-based nanoparticles. SLNs were developed to overcome the limitations of other colloidal carriers, such as emulsions, liposomes and polymeric nanoparticles because they have advantages like good release profile and targeted drug delivery with excellent physical stability. In the next generation of the lipid nanoparticle, NLCs are modified SLNs which improve the stability and capacity loading. Three structural models of NLCs have been proposed. These LNPs have potential applications in drug delivery field, research, cosmetics, clinical medicine, etc. This article focuses on features, structure and innovation of LNPs and presents a wide discussion about preparation methods, advantages, disadvantages and applications of LNPs by focusing on SLNs and NLCs. PMID:26504751

On the mechanism of charge transport in low density polyethylene

NASA Astrophysics Data System (ADS)

Upadhyay, Avnish K.; Reddy, C. C.

2017-08-01

Polyethylene based polymeric insulators, are being increasingly used in the power industry for their inherent advantages over conventional insulation materials. Specifically, modern power cables are almost made with these materials, replacing the mass-impregnated oil-paper cable technology. However, for ultra-high dc voltage applications, the use of these polymeric cables is hindered by ununderstood charge transport and accumulation. The conventional conduction mechanisms (Pool-Frenkel, Schottky, etc.) fail to track high-field charge transport in low density polyethylene, which is semi-crystalline in nature. Until now, attention was devoted mainly to the amorphous region of the material. In this paper, authors propose a novel mechanism for conduction in low density polyethylene, which could successfully track experimental results. As an implication, a novel, substantial relationship is established for electrical conductivity that could be effectively used for understanding conduction and breakdown in polyethylene, which is vital for successful development of ultra-high voltage dc cables.

Properties and oxidative stability of emulsions prepared with myofibrillar protein and lard diacylglycerols.

PubMed

Diao, Xiaoqin; Guan, Haining; Zhao, Xinxin; Chen, Qian; Kong, Baohua

2016-05-01

The objective of this study was to investigate the emulsifying properties and oxidative stability of emulsions prepared with porcine myofibrillar proteins (MPs) and different lipids, including lard, glycerolized lard (GL) and purified glycerolized lard (PGL). The GL and PGL emulsions had significantly higher emulsifying activity indices and emulsion stability indices than the lard emulsion (P<0.05). The PGL emulsion presented smaller droplet sizes, thus decreasing particle aggregation and improving emulsion stability. The static and dynamic rheological observations of the emulsions showed that the emulsions had pseudo-plastic behavior, and the PGL emulsion presented a larger viscosity and a higher storage modulus (G') and loss modulus (G'') compared with the other two emulsions (P<0.05). The formation of thiobarbituric acid-reactive substances, carbonyl contents and total sulfhydryl contents was not significantly different between the emulsions with PGL, GL and lard (P<0.05). In general, lard diacylglycerols enhanced emulsifying abilities and had no adverse effects on the oxidation stability of the emulsions prepared with MPs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Two-step emulsification process for water-in-oil-in-water multiple emulsions stabilized by lamellar liquid crystals.

PubMed

Ito, Toshifumi; Tsuji, Yukitaka; Aramaki, Kenji; Tonooka, Noriaki

2012-01-01

Multiple emulsions, also called complex emulsions or multiphase emulsions, include water-in-oil-in-water (W/O/W)-type and oil-in-water-in-oil (O/W/O)-type emulsions. W/O/W-type multiple emulsions, obtained by utilizing lamellar liquid crystal with a layer structure showing optical anisotropy at the periphery of emulsion droplets, are superior in stability to O/W/O-type emulsions. In this study, we investigated a two-step emulsification process for a W/O/W-type multiple emulsion utilizing liquid crystal emulsification. We found that a W/O/W-type multiple emulsion containing lamellar liquid crystal can be prepared by mixing a W/O-type emulsion (prepared by primary emulsification) with a lamellar liquid crystal obtained from poly(oxyethylene) stearyl ether, cetyl alcohol, and water, and by dispersing and emulsifying the mixture in an outer aqueous phase. When poly(oxyethylene) stearyl ether and cetyl alcohol are each used in a given amount and the amount of water added is varied from 0 to 15 g (total amount of emulsion, 100 g), a W/O/W-type multiple emulsion is efficiently prepared. When the W/O/W-type multiple emulsion was held in a thermostatic bath at 25°C, the droplet size distribution showed no change 0, 30, or 60 days after preparation. Moreover, the W/O/W-type multiple emulsion strongly encapsulated Uranine in the inner aqueous phase as compared with emulsions prepared by one-step emulsification.

Photoinitiated Polymerization-Induced Self-Assembly (Photo-PISA): New Insights and Opportunities.

PubMed

Yeow, Jonathan; Boyer, Cyrille

2017-07-01

The polymerization-induced self-assembly (PISA) process is a useful synthetic tool for the efficient synthesis of polymeric nanoparticles of different morphologies. Recently, studies on visible light initiated PISA processes have offered a number of key research opportunities that are not readily accessible using traditional thermally initiated systems. For example, visible light mediated PISA (Photo-PISA) enables a high degree of control over the dispersion polymerization process by manipulation of the wavelength and intensity of incident light. In some cases, the final nanoparticle morphology of a single formulation can be modulated by simple manipulation of these externally controlled parameters. In addition, temporal (and in principle spatial) control over the Photo-PISA process can be achieved in most cases. Exploitation of the mild room temperature polymerizations conditions can enable the encapsulation of thermally sensitive therapeutics to occur without compromising the polymerization rate and their activities. Finally, the Photo-PISA process can enable further mechanistic insights into the morphological evolution of nanoparticle formation such as the effects of temperature on the self-assembly process. The purpose of this mini-review is therefore to examine some of these recent advances that have been made in Photo-PISA processes, particularly in light of the specific advantages that may exist in comparison with conventional thermally initiated systems.

Experimental investigation of a page-oriented Lippmann holographic data storage system

NASA Astrophysics Data System (ADS)

Pauliat, Gilles; Contreras, Kevin

2010-06-01

Lippmann photography is a more than one century old interferometric process invented for recording colored images in thick black and white photographic emulsions. After a comparison between this photographic process and Denisyuk holography, we feature some hints to apply this technique to high density data storage by wavelength multiplexing in a page-oriented approach in thick media. For the first time we experimentally investigate this approach. We anticipated that this storage architecture should allow capacities as large as for conventional holography.

Genetically engineered nanocarriers for drug delivery.

PubMed

Shi, Pu; Gustafson, Joshua A; MacKay, J Andrew

2014-01-01

Cytotoxicity, low water solubility, rapid clearance from circulation, and off-target side-effects are common drawbacks of conventional small-molecule drugs. To overcome these shortcomings, many multifunctional nanocarriers have been proposed to enhance drug delivery. In concept, multifunctional nanoparticles might carry multiple agents, control release rate, biodegrade, and utilize target-mediated drug delivery; however, the design of these particles presents many challenges at the stage of pharmaceutical development. An emerging solution to improve control over these particles is to turn to genetic engineering. Genetically engineered nanocarriers are precisely controlled in size and structure and can provide specific control over sites for chemical attachment of drugs. Genetically engineered drug carriers that assemble nanostructures including nanoparticles and nanofibers can be polymeric or non-polymeric. This review summarizes the recent development of applications in drug and gene delivery utilizing nanostructures of polymeric genetically engineered drug carriers such as elastin-like polypeptides, silk-like polypeptides, and silk-elastin-like protein polymers, and non-polymeric genetically engineered drug carriers such as vault proteins and viral proteins.

Genetically engineered nanocarriers for drug delivery

PubMed Central

Shi, Pu; Gustafson, Joshua A; MacKay, J Andrew

2014-01-01

Cytotoxicity, low water solubility, rapid clearance from circulation, and off-target side-effects are common drawbacks of conventional small-molecule drugs. To overcome these shortcomings, many multifunctional nanocarriers have been proposed to enhance drug delivery. In concept, multifunctional nanoparticles might carry multiple agents, control release rate, biodegrade, and utilize target-mediated drug delivery; however, the design of these particles presents many challenges at the stage of pharmaceutical development. An emerging solution to improve control over these particles is to turn to genetic engineering. Genetically engineered nanocarriers are precisely controlled in size and structure and can provide specific control over sites for chemical attachment of drugs. Genetically engineered drug carriers that assemble nanostructures including nanoparticles and nanofibers can be polymeric or non-polymeric. This review summarizes the recent development of applications in drug and gene delivery utilizing nanostructures of polymeric genetically engineered drug carriers such as elastin-like polypeptides, silk-like polypeptides, and silk-elastin-like protein polymers, and non-polymeric genetically engineered drug carriers such as vault proteins and viral proteins. PMID:24741309

Alternative lipid emulsions versus pure soy oil based lipid emulsions for parenterally fed preterm infants.

PubMed

Kapoor, Vishal; Glover, Rebecca; Malviya, Manoj N

2015-12-02

The pure soybean oil based lipid emulsions (S-LE) conventionally used for parenteral nutrition (PN) in preterm infants have high polyunsaturated fatty acid (PUFA) content. The newer lipid emulsions (LE) from alternative lipid sources with reduced PUFA content may improve clinical outcomes in preterm infants. To determine the safety and efficacy of the newer alternative LE compared with the conventional S-LE for PN in preterm infants. We used the standard search strategy of the Cochrane Neonatal Review Group (CNRG) to search the Cochrane Central Register of Controlled Trials (CENTRAL; Issue 7), MEDLINE (1946 to 31 July 2015), EMBASE (1947 to 31 July 2015), CINAHL (1982 to 31 July 2015), Web of Science (31 July 2015), conference proceedings, trial registries (clinicaltrials.gov, controlled-trials.com, WHO's ICTRP), and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. Randomised or quasi-randomised controlled trials in preterm infants (< 37 weeks), comparing newer alternative LE with S-LE. Data collection and analysis conformed to the methods of the CNRG. We assessed the quality of evidence for important outcomes using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, in addition to reporting the conventional statistical significance of results. Fifteen studies (N = 979 infants) are included in this review. Alternative LE including medium chain triglycerides/long chain triglycerides (MCT/LCT) LE (3 studies; n = 108), MCT-olive-fish-soy oil-LE (MOFS-LE; 7 studies; n = 469), MCT-fish-soy oil-LE (MFS-LE; 1 study; n = 60), olive-soy oil-LE (OS-LE; 7 studies; n = 406), and borage-soy oil-LE (BS-LE; 1 study; n = 34) were compared with S-LE. The different LE were also considered together to compare 'all fish oil containing-LE' versus S-LE (7 studies; n = 499) and 'all alternative LE' versus S-LE (15 studies; n = 979). Some studies had multiple intervention arms and were included in more than one comparison. No study compared pure fish oil-LE or structured-LE to S-LE.The GRADE quality of evidence (GRADE QoE) ranged from 'low' to 'very low.' Evidence came mostly from small single centre studies, many focusing on biochemical aspects as their primary outcomes, with optimal information size not achieved for the important clinical outcomes in any comparison.In the primary outcomes of the review there was a pooled effect towards decreased bronchopulmonary dysplasia (BPD) in OS-LE vs S-LE (4 studies, n = 261) not reaching statistical significance (typical risk ratio (RR) 0.69, 95% confidence interval (CI) 0.46 to 1.04, I² = 32%; typical risk difference (RD) -0.08, 95% CI -0.17 to 0.00, I² = 76%; GRADE QoE: 'very low'). No difference in BPD was observed in any other comparison. There were no statistically significant differences in the primary outcomes of death, growth rate (g/kg/day) or days to regain birth weight in any comparison.Retinopathy of prematurity (ROP) stage 1-2 was reported to be statistically significantly lower in one single centre study (n = 80) in the MOFS-LE group compared with the S-LE group (1/40 vs 12/40, respectively; RR 0.08, 95% CI 0.01 to 0.61; RD -0.27, 95% CI -0.43 to -0.12; number needed to benefit (NNTB) 4, 95% CI 2 to 8). However there were no statistically significant differences in the secondary outcome of ROP ≥ stage 3 in any of the individual studies or in any comparison (GRADE QoE: 'low' to 'very low'). No other study reported on ROP stages 1 and 2 separately.There were no statistically significant differences in the secondary outcomes of sepsis, PN associated liver disease (PNALD)/cholestasis, ventilation duration, necrotising enterocolitis (NEC) ≥ stage 2, jaundice requiring treatment, intraventricular haemorrhage grade III-IV, periventricular leukomalacia (PVL), patent ductus arteriosus (PDA), hypertriglyceridaemia, and hyperglycaemia in any comparison.No study reported on neurodevelopmental outcomes or essential fatty acid deficiency. All lipid emulsions in this review appeared to be safe and were well tolerated in preterm infants. Compared with the pure soy oil based LE, use of MOFS-LE was associated with a decrease in the early stages (1-2) of ROP in one study. However there were no statistically significant differences in clinically important outcomes including death, growth, BPD, sepsis, ROP ≥ stage 3, and PNALD with the use of newer alternative LE versus the conventional pure soy oil based LE (GRADE QoE ranged from 'low' to 'very low'). Currently there is insufficient evidence to recommend any alternative LE over S-LE or vice versa in preterm infants.Larger randomised studies focusing on important clinical outcomes, targeting specific 'at risk' population subgroups (e.g. extreme prematurity, long term PN, etc), and exploring the effect of different proportions of lipid constituents are required to evaluate the effectiveness of newer lipid emulsions compared with the conventional pure soy based LE in preterm infants.

Redox-responsive solid lipid microparticles composed of octadecyl acrylate and allyl disulfide.

PubMed

Kim, Tae Hoon; Kim, Jin-Chul

2018-04-01

Redox-responsive solid lipid microparticles were prepared by an emulsification photo-polymerization method. Octadecyl acrylate (ODA) and a cross-linker (i.e. allyl disulfide (ADS) and octadiene (ODE)) were dissolved in dichloromethane, it was emulsified in poly(vinyl alcohol) solution, and the resulting O/W emulsion was irradiated with UV light. On the scanning electron microscope micrographs, the microparticles were sphere-like and they were not markedly different from the oil droplets in size. Using the atomic compositions analyzed by energy dispersive X-ray spectroscopy, the ODA to cross-linker molar ratio of ODA/ADS microparticles and ODA/ODE ones were calculated to be 1:0.13 and 1:0.15, respectively. In the FT-IR spectra of the microparticles, the signal of the vinyl group was hardly detected, implying that the monomer and the cross-linkers participated in the photo-polymerization. In differential scanning calorimetry study, ODA/ADS microparticles and ODA/ODE ones exhibited their endothermic peaks around 42.9 and 41.3 °C, respectively, possibly due to the melting of polymeric ODA. Dithiothreitol (DTT, a reducing agent) concentration had little effect on the release degree of dye loaded in ODA/ODE microparticles. Whereas, DTT concentration had a significant effect on the release degree of dye loaded in ODA/ADS microparticles. The release degree at 26 °C was weakly affected by DTT concentration. When the temperature was 37 °C, DTT concentration had a strong effect on the release degree. The disulfide cross-linker (i.e. ADS) can be broken to thiol compounds by the reducing agent, resulting in an increase in the release degree.

Adsorption and covalent binding of fibrinogen as a method for probing the chemical composition of poly(styrene/α-tert-butoxy-ω-vinylbenzyl-polyglycidol) microsphere surfaces.

PubMed

Gosecka, Monika; Chehimi, Mohamed M; Basinska, Teresa; Slomkowski, Stanislaw; Makowski, Tomasz

2017-12-01

We investigated the distribution of polyglycidol and polystyrene on the surface of poly(styrene/α-tert-butoxy-ω-vinylbenzyl-polyglycidol) microspheres (random distribution or segregated into hydrophilic and hydrophobic patches), using fibrinogen (Fb) as a macromolecular probe. The fibrinogen was adsorbed or covalently attached to the surface of the poly(styrene-co-α-tert-butoxy-ω-vinylbenzyl-polyglycidol) (P(S/PGLy)) microspheres. The P(S/PGLy) particles were prepared by emulsion copolymerization of styrene and α-tert-butoxy-ω-vinylbenzyl-polyglycidol (PGLy) macromonomer initiated with potassium persulfate. The polymerizations yielded P(S/PGLy) particles with various surface fractions of polyglycidol, depending on the amount of added macromonomer and the addition process. In some syntheses, the entire macromonomer amount was added once at the beginning of the polymerization, while in others, the macromonomer was added gradually after the formation of particle seeds from pure polystyrene. XPS studies revealed that the fraction of polyglycidol in the interfacial layer of the microspheres was larger when the entire amount of macromonomer was added at the beginning of the polymerization than when it was added after formation of the polystyrene seeds. Studies of fibrinogen adsorption provided the first evidence of segregation of the hydrophobic (polystyrene) and hydrophilic (polyglycidol) components at the surface of the composite P(S/PGLy) microspheres into patches. The hydrophobic patches are composed mainly of polystyrene. However, they also contain a small amount of polyglycidol chains, making the adsorption of fibrinogen weaker than the adsorption onto the pure polystyrene. Studies of covalent immobilization of fibrinogen on the microspheres via 1,3,5-trichlorotriazine confirmed these findings. Copyright © 2017 Elsevier B.V. All rights reserved.

Food emulsions as delivery systems for flavor compounds: A review.

PubMed

Mao, Like; Roos, Yrjö H; Biliaderis, Costas G; Miao, Song

2017-10-13

Food flavor is an important attribute of quality food, and it largely determines consumer food preference. Many food products exist as emulsions or experience emulsification during processing, and therefore, a good understanding of flavor release from emulsions is essential to design food with desirable flavor characteristics. Emulsions are biphasic systems, where flavor compounds are partitioning into different phases, and the releases can be modulated through different ways. Emulsion ingredients, such as oils, emulsifiers, thickening agents, can interact with flavor compounds, thus modifying the thermodynamic behavior of flavor compounds. Emulsion structures, including droplet size and size distribution, viscosity, interface thickness, etc., can influence flavor component partition and their diffusion in the emulsions, resulting in different release kinetics. When emulsions are consumed in the mouth, both emulsion ingredients and structures undergo significant changes, resulting in different flavor perception. Special design of emulsion structures in the water phase, oil phase, and interface provides emulsions with great potential as delivery systems to control flavor release in wider applications. This review provides an overview of the current understanding of flavor release from emulsions, and how emulsions can behave as delivery systems for flavor compounds to better design novel food products with enhanced sensorial and nutritional attributes.

Agglutination of intravenously administered phosphatidylcholine-containing lipid emulsions with serum C-reactive protein.

PubMed

Tugirimana, Pierrot; Speeckaert, Marijn M; Fiers, Tom; De Buyzere, Marc L; Kint, Jos; Benoit, Dominique; Delanghe, Joris R

2013-04-01

C-reactive protein (CRP) is able to bind phospholipids in the presence of calcium. We wanted to investigate the reaction of CRP with various commercial fat emulsions and to explore the impact of CRP agglutination on serum CRP levels. Serum specimens were mixed with Intralipid 20% (soybean oil-based fat emulsion), Structolipid (structured oil-based fat emulsion), Omegaven (fish oil-based fat emulsion), or SMOFlipid (mixed soybean oil-, olive oil-, and fish oil-based emulsion) in Tris-calcium buffer (pH 7.5). After 30 minutes of incubation at 37°C, CRP-phospholipid complexes were turbidimetrically quantified and flow cytometric analysis was performed. Similarly, CRP complexes were monitored in vivo, following administration of fat emulsion. CRP was able to agglutinate phospholipid-containing lipid droplets present in the soybean oil-based fat emulsion and the structured oil-based fat emulsion. To a lesser extent, agglutination was observed for fish oil-containing fat emulsions, whereas no agglutination was noticed for the mixed soybean oil-, olive oil-, and fish oil-based emulsion. Results for propofol-containing emulsions were comparable. Agglutination correlated with phospholipid content of the emulsions. When in vivo agglutination occurred, plasma CRP values dropped due to consumption of CRP by phospholipid-induced agglutination. In this in vitro experiment, we demonstrated agglutination of CRP with phospholipids in various fat emulsions. Research studies are required in patients to determine which effects occur with various intravenous fat emulsions.

Swelling-induced optical anisotropy of thermoresponsive hydrogels based on poly(2-(2-methoxyethoxy)ethyl methacrylate): deswelling kinetics probed by quantitative Mueller matrix polarimetry.

PubMed

Patil, Nagaraj; Soni, Jalpa; Ghosh, Nirmalya; De, Priyadarsi

2012-11-29

Thermodynamically favored polymer-water interactions below the lower critical solution temperature (LCST) caused swelling-induced optical anisotropy (linear retardance) of thermoresponsive hydrogels based on poly(2-(2-methoxyethoxy)ethyl methacrylate). This was exploited to study the macroscopic deswelling kinetics quantitatively by a generalized polarimetry analysis method, based on measurement of the Mueller matrix and its subsequent inverse analysis via the polar decomposition approach. The derived medium polarization parameters, namely, linear retardance (δ), diattenuation (d), and depolarization coefficient (Δ), of the hydrogels showed interesting differences between the gels prepared by conventional free radical polymerization (FRP) and reversible addition-fragmentation chain transfer polymerization (RAFT) and also between dry and swollen state. The effect of temperature, cross-linking density, and polymerization technique employed to synthesize hydrogel on deswelling kinetics was systematically studied via conventional gravimetry and corroborated further with the corresponding Mueller matrix derived quantitative polarimetry characteristics (δ, d, and Δ). The RAFT gels exhibited higher swelling ratio and swelling-induced optical anisotropy compared to FRP gels and also deswelled faster at 30 °C. On the contrary, at 45 °C, deswelling was significantly retarded for the RAFT gels due to formation of a skin layer, which was confirmed and quantified via the enhanced diattenuation and depolarization parameters.

Synthesis of a proline-modified acrylic acid copolymer in supercritical CO2 for glass-ionomer dental cement applications.

PubMed

Moshaverinia, Alireza; Roohpour, Nima; Darr, Jawwad A; Rehman, Ihtesham U

2009-06-01

Supercritical (sc-) fluids (such as sc-CO(2)) represent interesting media for the synthesis of polymers in dental and biomedical applications. Sc-CO(2) has several advantages for polymerization reactions in comparison to conventional organic solvents. It has several advantages in comparison to conventional polymerization solvents, such as enhanced kinetics, being less harmful to the environment and simplified solvent removal process. In our previous work, we synthesized poly(acrylic acid-co-itaconic acid-co-N-vinylpyrrolidone) (PAA-IA-NVP) terpolymers in a supercritical CO(2)/methanol mixture for applications in glass-ionomer dental cements. In this study, proline-containing acrylic acid copolymers were synthesized, in a supercritical CO(2) mixture or in water. Subsequently, the synthesized polymers were used in commercially available glass-ionomer cement formulations (Fuji IX commercial GIC). Mechanical strength (compressive strength (CS), diametral tensile strength (DTS) and biaxial flexural strength (BFS)) and handling properties (working and setting time) of the resulting modified cements were evaluated. It was found that the polymerization reaction in an sc-CO(2)/methanol mixture was significantly faster than the corresponding polymerization reaction in water and the purification procedures were simpler for the former. Furthermore, glass-ionomer cement samples made from the terpolymer prepared in sc-CO(2)/methanol exhibited higher CS and DTS and comparable BFS compared to the same polymer synthesized in water. The working properties of glass-ionomer formulations made in sc-CO(2)/methanol were comparable and better than the values of those for polymers synthesized in water.

Influence of the collection tube on metabolomic changes in serum and plasma.

PubMed

López-Bascón, M A; Priego-Capote, F; Peralbo-Molina, A; Calderón-Santiago, M; Luque de Castro, M D

2016-04-01

Major threats in metabolomics clinical research are biases in sampling and preparation of biological samples. Bias in sample collection is a frequently forgotten aspect responsible for uncontrolled errors in metabolomics analysis. There is a great diversity of blood collection tubes for sampling serum or plasma, which are widely used in metabolomics analysis. Most of the existing studies dealing with the influence of blood collection on metabolomics analysis have been restricted to comparison between plasma and serum. However, polymeric gel tubes, which are frequently proposed to accelerate the separation of serum and plasma, have not been studied. In the present research, samples of serum or plasma collected in polymeric gel tubes were compared with those taken in conventional tubes from a metabolomics perspective using an untargeted GC-TOF/MS approach. The main differences between serum and plasma collected in conventional tubes affected to critical pathways such as the citric acid cycle, metabolism of amino acids, fructose and mannose metabolism and that of glycerolipids, and pentose and glucuronate interconversion. On the other hand, the polymeric gel only promoted differences at the metabolite level in serum since no critical differences were observed between plasma collected with EDTA tubes and polymeric gel tubes. Thus, the main changes were attributable to serum collected in gel and affected to the metabolism of amino acids such as alanine, proline and threonine, the glycerolipids metabolism, and two primary metabolites such as aconitic acid and lactic acid. Therefore, these metabolite changes should be taken into account in planning an experimental protocol for metabolomics analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Use of olive oil-in-water gelled emulsions in model turkey breast emulsions

NASA Astrophysics Data System (ADS)

Serdaroğlu, M.; Öztürk, B.

2017-09-01

Today, gelled emulsion systems offer a novel possibility in lipid modification of meat products. In this study, we aimed to investigate the quality characteristics of model turkey emulsions that were prepared with olive oil-in-water gelled emulsion (GE) as partial or total beef fat replacer. The results indicated that while most of the GE treatments showed equivalent emulsion characteristics in terms of emulsion stability, water-holding capacity and cook yield, utilization of 100% GE as the lipid source could increase total expressible fluid of the model turkey emulsion and thus negatively affect the quality. Utilization of GE was effective in total fat reduction, as the model turkey emulsions formulated with more than 50% GE had significantly lower fat content compared to full-beef fat control model emulsion. However, beef fat replacement with GE produced considerable changes in colour parameters. Finally, it was concluded that utilization of GE as a partial beef fat replacer has good potential to enhance stability and reduce total fat in turkey meat emulsion products.

Computed tomography-guided screening of surfactant effect on blood circulation time of emulsions: application to the design of an emulsion formulation for paclitaxel.

PubMed

Lee, Eun-Hye; Hong, Soon-Seok; Kim, So Hee; Lee, Mi-Kyung; Lim, Joon Seok; Lim, Soo-Jeong

2014-08-01

In an effort to apply the imaging techniques currently used in disease diagnosis for monitoring the pharmacokinetics and biodisposition of particulate drug carriers, we sought to use computed tomography (CT) scanning methodology to investigate the impact of surfactant on the blood residence time of emulsions. We prepared the iodinated oil Lipiodol emulsions with different compositions of surfactants and investigated the impact of surfactant on the blood residence time of emulsions by CT scanning. The blood circulation time of emulsions was prolonged by including Tween 80 or DSPE-PEG (polyethylene glycol 2000) in emulsions. Tween 80 was less effective than DSPE-PEG in terms of prolongation effect, but the blood circulating time of emulsions was prolonged in a Tween 80 content-dependent manner. As a proof-of-concept demonstration of the usefulness of CT-guided screening in the process of formulating drugs that need to be loaded in emulsions, paclitaxel was loaded in emulsions prepared with 87 or 65% Tween 80-containing surfactant mixtures. A pharmacokinetics study showed that paclitaxel loaded in 87% Tween 80 emulsions circulated longer in the bloodstream compared to those in 65% Tween 80 emulsions, as predicted by CT imaging. CT-visible, Lipiodol emulsions enabled the simple evaluation of surfactant composition effects on the biodisposition of emulsions.

Development of High Sensitivity Nuclear Emulsion and Fine Grained Emulsion

NASA Astrophysics Data System (ADS)

Kawahara, H.; Asada, T.; Naka, T.; Naganawa, N.; Kuwabara, K.; Nakamura, M.

2014-08-01

Nuclear emulsion is a particle detector having high spacial resolution and angular resolution. It became useful for large statistics experiment thanks to the development of automatic scanning system. In 2010, a facility for emulsion production was introduced and R&D of nuclear emulsion began at Nagoya university. In this paper, we present results of development of the high sensitivity emulsion and fine grained emulsion for dark matter search experiment. Improvement of sensitivity is achieved by raising density of silver halide crystals and doping well-adjusted amount of chemicals. Production of fine grained emulsion was difficult because of unexpected crystal condensation. By mixing polyvinyl alcohol (PVA) to gelatin as a binder, we succeeded in making a stable fine grained emulsion.

A Novel, Aqueous Surface Treatment To Thermally Stabilize High Resolution Positive Photoresist Images*

NASA Astrophysics Data System (ADS)

Grunwald, John J.; Spencer, Allen C.

1986-07-01

The paper describes a new approach to thermally stabilize the already imaged profile of high resolution positive photoresists such as ULTRAMAC" PR-914. ***XD-4000, an aqueous emulsion of a blend of fluorine-bearing compounds is spun on top of the developed, positive photoresist-imaged wafer, and baked. This allows the photoresist to withstand temperatures up to at least 175 deg. C. while essentially maintaining vertical edge profiles. Also, adverse effects of "outgassing" in harsh environments, ie., plasma and ion implant are greatly minimized by allowing the high resolution imaged photoresist to be post-baked at "elevated" temperatures. Another type of product that accomplishes the same effect is ***XD-4005, an aqueous emulsion of a high temperature-resistant polymer. While the exact mechanism is yet to be identified, it is postulated that absorption of the "polymeric" species into the "skin" of the imaged resist forms a temperature resistant "envelope", thereby allowing high resolution photoresists to also serve in a "high temperature" mode, without reticulation, or other adverse effects due to thermal degradation. SEM's are presented showing imaged ULTRAMAC" PR-914 and ULTRAMAC" **EPA-914 geometries coated with XD-4000 or XD-4005 and followed by plasma etched oxide,polysilicon and aluminum. Selectivity ratios are compared with and without the novel treatment and are shown to be significantly better with the treatment. The surface-treated photoresist for thermal resistance remains easily strippable in solvent-based or plasma media, unlike photoresists that have undergone "PRIST" or other gaseous thermal stabilization methods.

pH-sensitive wax emulsion copolymerization with acrylamide hydrogel using gamma irradiation for dye removal

NASA Astrophysics Data System (ADS)

Ghobashy, Mohamed Mohamady; Elhady, Mohamed., A.

2017-05-01

Emulsion polymerization is an efficient method for the production of new wax-hydrogel matrices of cetyl alcohol: stearic acid wax and acrylamide hydrogel using triethylamine (TEA) as an emulsifier. A cross-linking reaction occurred when a mixture of wax-hydrogel solution was irradiated with gamma rays at a dose of 20 kGy. The gelation percentage of the matrices (CtOH-StA/PAAm) was 86%, which indicates that a sufficiently high conversion occurred in these new wax-hydrogel matrices. The ability of PAAm and CtOH-StA/PAAm as an adsorbent for dye removal was investigated. The removal of three reactive dyes, namely Remazol Red (RR), Amido Black (AB), and Toluidine Blue (TB), from aqueous solutions depends on the pH of the dye solution. Removal efficiency was investigated by UV spectrophotometry, and the results showed the affinity of the wax hydrogel to adsorb TB was 98% after 320 min. Fourier transform infrared-attenuated total reflectance spectra confirmed the cross-linking process involved between the chains of wax and hydrogel; furthermore, scanning electron microscopy images showed that the wax and hydrogel were completely miscible to form a single matrix. Swelling measurements showed the high affinity of adsorbed dyes from aqueous solutions at different pH values to the wax-hydrogel network; the highest swelling values of 13.05 and 8.24 (g/g) were observed at pH 10 and 6, respectively

Polymeric nanoparticles of siRNA prepared by a double-emulsion solvent-diffusion technique: Physicochemical properties, toxicity, biodistribution and efficacy in a mammary carcinoma mice model.

PubMed

Ben David-Naim, Meital; Grad, Etty; Aizik, Gil; Nordling-David, Mirjam M; Moshel, Ofra; Granot, Zvi; Golomb, Gershon

2017-11-01

siRNA-loaded nanoparticles (NPs) administered systemically can overcome the poor stability and rapid elimination of free double-stranded RNA in circulation, resulting in increased tumor accumulation and efficacy. siRNA against osteopontin (siOPN), a protein involved in breast cancer development, was encapsulated in poly(D,L-lactic-co-glycolic acid) NPs by a double emulsion solvent diffusion (DESD) technique. We also compared the effect of polyethylenimine (PEI) molecular weight (800 Da and 25 kDa), used as the counter-ion for siRNA complexation, on the physicochemical properties of the NPs, cytotoxicity, and cellular uptake. NPs prepared by the DESD technique were obtained at the desired size (∼170 nm) using both types of PEIs, and were characterized with a neutral surface charge, high encapsulation yield (up to ∼60%), siOPN concentration of 5.6-8.4 μg/mg, stability in physiologic conditions in vitro and in vivo, and long-term shelf-life stability (> 3 years). The NPs prepared using both PEIs exhibited no cytotoxicity in primary smooth muscle culture, and no detrimental effect on mice liver enzymes following their IV administration. Following cellular uptake and biodistribution studies, the therapeutic potential of the NPs was demonstrated by a significant decrease of tumor progression and size in an ectopic xenograft model of mammary carcinoma in mice. Copyright © 2017 Elsevier Ltd. All rights reserved.

Covalent attachment of microbial lipase onto microporous styrene-divinylbenzene copolymer by means of polyglutaraldehyde.

PubMed

Dizge, Nadir; Keskinler, Bülent; Tanriseven, Aziz

2008-10-01

A novel method for immobilization of Thermomyces lanuginosus lipase onto polyglutaraldehyde-activated poly(styrene-divinylbenzene) (STY-DVB), which is a hydrophobic microporous support has been successfully developed. The copolymer was prepared by the polymerization of the continuous phase of a high internal phase emulsion (polyHIPE). The concentrated emulsion consists of a mixture of styrene and divinylbenzene containing a suitable surfactant and an initiator as the continuous phase and water as the dispersed phase. Lipase from T. lanuginosus was immobilized covalently with 85% yield on the internal surface of the hydrophobic microporous poly(styrene-divinylbenzene) copolymer and used as a biocatalyst for the transesterification reaction. The immobilized enzyme has been fully active 30 days in storage and retained the activity during the 15 repeated batch reactions. The properties of free and immobilized lipase were studied. The effects of protein concentration, pH, temperature, and time on the immobilization, activity, and stability of the immobilized lipase were also studied. The newly synthesized microporous poly(styrene-divinylbenzene) copolymer constitutes excellent support for lipase. It given rise to high immobilization yield, retains enzymatic activity for 30 days, stable in structure and allows for the immobilization of large amount of protein (11.4mg/g support). Since immobilization is simple yet effective, the newly immobilized lipase could be used in several application including oil hydrolysis, production of modified oils, biodiesel synthesis, and removal of fatty acids from oils.

Studies on ocular and parenteral application potentials of azithromycin- loaded anionic, cationic and neutral-charged emulsions.

PubMed

Tamilvanan, Shunmugaperumal; Khanum, Ramona; Senthilkumar, Sudalimuthu Ramachandran; Muthuraman, Marimuthu; Rajasekharan, Thenrajan

2013-10-01

Ocular and parenteral application potentials of azithromycin-containing, non-phospholipid-based cationic nanosized emulsion in comparison to the phospholipid-based anionic and neutral-charged nanosized emulsions were investigated. Various physical, chemical, nonclinical toxicity and antimicrobial activity studies (mean droplet diameter, surface charge, creaming index, entrapment efficiency, accelerated, long-term and freeze-thaw cycling stabilities, TLC study, modified hen's egg chorioallantoic membrane (HET-CAM) test, in vitro hemolysis test, in vitro and in vivo myotoxicity, and in vitro antimicrobial activity) were conducted for assessing the potentials of these three types of emulsions. Following autoclave sterilization, all of these emulsions exhibited a nanometer range mean particle diameter (200 ± 29 to 434 ± 13 nm). While the anionic and cationic emulsions did show high negative (-34.2 ± 1.23 mV) and positive zeta potential (42.6 ± 1.45 mV) values, the neutral-charged emulsion did not. Even with 5 freeze-thaw cycles, the cationic emulsion remained stable whereas other two emulsions underwent phase-separation. The hen's egg chorioallantoic membrane test revealed an irritation score value that was higher for the anionic emulsion than for cationic or neutral-charged emulsion. A significantly higher % hemolysis value was also noticed for the anionic emulsion when compared to the % hemolysis value of cationic emulsion (ANOVA, P ‹ 0.05). However, all of the emulsions showed a lesser intracellular creatine kinase (CK) release/plasma CK level in comparison to the positive control (phenytoin) indicating their lesser myotoxicity at the injection site . When compared to anionic and neutral-charged emulsions, the possible controlled drug release from cationic emulsion delayed the in vitro antimicrobial action against H.influenzae and S.pneumoniae.

40 CFR 467.20 - Applicability; description of the rolling with emulsions subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... rolling with emulsions subcategory. 467.20 Section 467.20 Protection of Environment ENVIRONMENTAL... Rolling With Emulsions Subcategory § 467.20 Applicability; description of the rolling with emulsions... the rolling with emulsions subcategory. ...

40 CFR 467.20 - Applicability; description of the rolling with emulsions subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... rolling with emulsions subcategory. 467.20 Section 467.20 Protection of Environment ENVIRONMENTAL... Rolling With Emulsions Subcategory § 467.20 Applicability; description of the rolling with emulsions... the rolling with emulsions subcategory. ...

Physical and antimicrobial properties of thyme oil emulsions stabilized by ovalbumin and gum arabic.

PubMed

Niu, Fuge; Pan, Weichun; Su, Yujie; Yang, Yanjun

2016-12-01

Natural biopolymer stabilized oil-in-water emulsions were formulated using ovalbumin (OVA), gum arabic (GA) solutions and their complexes. The influence of interfacial structure of emulsion (OVA-GA bilayer and OVA/GA complexes emulsions) on the physical properties and antimicrobial activity of thyme oil (TO) emulsion against Escherichia coli (E. coli) was evaluated. The results revealed that the two types of emulsions with different oil phase compositions remained stable during a long storage period. The oil phase composition had an appreciable influence on the mean particle diameter and retention of the TO emulsions. The stable emulsion showed a higher minimum inhibitory concentration (MIC), and the TO emulsions showed an improved long-term antimicrobial activity compared to the pure thyme oil, especially complexes emulsion at pH 4.0. These results provided useful information for developing protection and delivery systems for essential oil using biopolymer. Copyright © 2016 Elsevier Ltd. All rights reserved.

Creating nanoscale emulsions using condensation.

PubMed

Guha, Ingrid F; Anand, Sushant; Varanasi, Kripa K

2017-11-08

Nanoscale emulsions are essential components in numerous products, ranging from processed foods to novel drug delivery systems. Existing emulsification methods rely either on the breakup of larger droplets or solvent exchange/inversion. Here we report a simple, scalable method of creating nanoscale water-in-oil emulsions by condensing water vapor onto a subcooled oil-surfactant solution. Our technique enables a bottom-up approach to forming small-scale emulsions. Nanoscale water droplets nucleate at the oil/air interface and spontaneously disperse within the oil, due to the spreading dynamics of oil on water. Oil-soluble surfactants stabilize the resulting emulsions. We find that the oil-surfactant concentration controls the spreading behavior of oil on water, as well as the peak size, polydispersity, and stability of the resulting emulsions. Using condensation, we form emulsions with peak radii around 100 nm and polydispersities around 10%. This emulsion formation technique may open different routes to creating emulsions, colloidal systems, and emulsion-based materials.