Science.gov

Sample records for soap-free emulsion copolymerization

  1. 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.

  2. 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. PMID:24114322

  3. Nonspherical nanoparticles with controlled morphologies via seeded surface-initiated single electron transfer radical polymerization in soap-free emulsion.

    PubMed

    Yuan, Jinfeng; Wang, Lixia; Zhu, Lei; Pan, Mingwang; Wang, Wenjie; Liu, Ying; Liu, Gang

    2015-04-14

    This work reports a facile novel approach to prepare asymmetric poly(vinylidene fluoride)/polystyrene (PVDF/PS) composite latex particles with controllable morphologies using one-step soap-free seeded emulsion polymerization, i.e., surface-initiated single electron transfer radical polymerization (SET-RP) of styrene (St) at the surface of PVDF seed particles. It was observed that the morphology was influenced mainly by the St/PVDF feed ratio, the polymerization temperature, and the length of the catalyst Cu(0) wire (Φ 1.00 mm). When the feed ratio was St/PVDF = 5.0 g/1.0 g, snowman-like Janus particles were exclusively obtained. Raspberry-like and popcorn-like composite particles were observed at a higher reaction temperature or a shorter length of the catalyst wire. The reaction kinetics plots demonstrated some unique features. The formation of nonspherical composite nanoparticles can be ascribed to the surface nucleation of PS bulges following the SET-RP. PMID:25797695

  4. 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

    2016-08-01

    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. PMID:27389855

  5. Oxygen and carbon dioxide dual gas-responsive and switchable microgels prepared from emulsion copolymerization of fluoro- and amino-containing monomers.

    PubMed

    Lei, Lei; Zhang, Qi; Shi, Shuxian; Zhu, Shiping

    2015-02-24

    We report herein the design and preparation of microgels that are responsive to both O2 and CO2 gases. The microgels were synthesized through soap-free emulsion copolymerization of O2-responsive monomer 2,3,4,5,6-pentafluorostyrene (FS) and CO2-responsive monomer 2-(diethylamino)ethyl methacrylate (DEA) with N,N'-methylenebis(acrylamide) (BisAM) as the cross-linker. The P(DEA-co-FS) microgels dispersed in aqueous solution could undergo volume phase transitions triggered by O2 and/or CO2 aeration. The particles were very responsive to CO2, while their responsivity to O2 was moderate. Microgels having different levels of the responsivity could be designed and prepared by varying the FS content in the copolymer. The phase transitions were also highly reversible, and the initial states of microgels could be easily recovered by "washing off" the trigger gases with N2. Multicycle O2, CO2, and N2 aerations were applied, and no loss in the dual gas responsivity and switchability was observed. PMID:25643178

  6. 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.

  7. Modification of flax fibres by radiation induced emulsion graft copolymerization of glycidyl methacrylate

    NASA Astrophysics Data System (ADS)

    Moawia, Rihab Musaad; Nasef, Mohamed Mahmoud; Mohamed, Nor Hasimah; Ripin, Adnan

    2016-05-01

    Flax fibres were modified by radiation induced graft copolymerization of glycidyl methacrylate (GMA) by pre-irradiation method in an emulsion medium. The effect of reaction parameters on the degree of grafting (DOG) such as concentration of bleaching agent, absorbed dose, monomer concentration, temperature and reaction time were investigated. The DOG was found to be dependent on the investigated parameters. The incorporation of poly(GMA) grafts in the bleached flax fibres was confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The structural and mechanical changes were evaluated by X-ray diffraction (XRD) and mechanical tester, respectively. The results revealed that reacting bleached flax fibres irradiated with 20 kGy with 5% GMA emulsion containing 0.5% polyoxyethylene-sorbitan monolaurate (Tween 20) surfactant at 40 °C for 1 h led to a maximum DOG of 148%. The grafted fibres showed sufficient mechanical strength and hydrophobicity which make them promising precursors for development of adsorbents after appropriate chemical treatments.

  8. 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. PMID:25617612

  9. Facile Soap-Free Miniemulsion Polymerization of Methyl Methacrylate via Reverse Atom Transfer Radical Polymerization.

    PubMed

    Zhu, Gaohua; Zhang, Lifen; Pan, Xiangqiang; Zhang, Wei; Cheng, Zhenping; Zhu, Xiulin

    2012-12-21

    A facile soap-free miniemulsion polymerization of methyl methacrylate (MMA) was successfully carried out via a reverse ATRP technique, using a water-soluble potassium persulfate (KPS) or 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V-50) both as the initiator and the stabilizer, and using an oil-soluble N,N-n-butyldithiocarbamate copper (Cu(S2CN(C4H9)2)2) as the catalyst without adding any additional ligand. Polymerization results demonstrated the "living"/controlled characteristics of ATRP and the resultant latexes showed good colloidal stability with average particle size around 300-700 nm in diameter. The monomer droplet nucleation mechanism was proposed. NMR spectroscopy and chain-extension experiments under UV light irradiation confirmed the attachment and livingness of UV light sensitive -S-C(=S)-N(C4H9)2 group in the chain end. PMID:23019131

  10. Chain Transfer of Vegetable Oil Macromonomers in Acrylic Solution Copolymerization

    SciTech Connect

    Black, Micah; Messman, Jamie M; Rawlins, James

    2011-01-01

    Use of vegetable oil macromonomers (VOMMs) as comonomers in emulsion polymerization enables good film coalescence without the addition of solvents that constitute volatile organic compounds (VOCs). VOMMs are derived from renewable resources and offer the potential of post-application crosslinking via auto-oxidation. However, chain transfer reactions of VOMMs with initiator and/or polymer radicals during emulsion polymerization reduce the amount of allylic hydrogen atoms available for primary auto-oxidation during drying. Vegetable oils and derivatives were reacted in combination with butyl acrylate and methyl methacrylate via solution polymerization. The copolymerization was monitored using in situ infrared spectroscopy to determine the extent of chain transfer. 1H NMR spectroscopy was used to determine the loci of chain transfer and the molecular weight characteristics of the polymers were characterized by SEC. Solution polymerization was utilized to minimize temperature fluctuations and maintain polymer solubility during the initial characterization.

  11. Steric stabilization of Pickering emulsions for the efficient synthesis of polymeric microcapsules.

    PubMed

    Salari, Joris W O; van Heck, Jeroen; Klumperman, Bert

    2010-09-21

    It is commonly known that Pickering emulsions are extremely stable against coalescence and are, therefore, potentially interesting for the synthesis of new materials, such as colloidosomes, microcapsules, composite particles, foams, and so on. However, for the efficient synthesis of such materials, one also has to consider the colloidal stability against aggregation, which is often neglected. In this study, it is demonstrated that steric stabilization is provided to Pickering emulsion droplets by the adsorption of poly(styrene-block-ethylene-co-propylene) (pS-b-EP) and that it is a requirement for the efficient synthesis of polymeric microcapsules. Monodisperse polystyrene particles of 648 nm are synthesized by soap-free emulsion polymerization. A model Pickering emulsion is then formed by the addition of sodium chloride at a critical concentration of 325 mM and mixing it with either heptane or decane. Subsequently, pS-b-EP is added to the Pickering emulsion to provide steric stabilization. Size exclusion chromatography is used to prove and quantify the adsorption of pS-b-EP onto the Pickering emulsion droplets. A maximum surface coverage of 1.3 mg/m(2) is obtained after 2 h, which is approximately one-third of the adsorption on a pure pS surface. We believe that the presence of polar sulfate groups on the particle, which initially stabilized the particle in water, reduces the adsorption of pS-b-EP. Microcapsules are formed by heating the Pickering emulsion above the glass-transition temperature of the particles. Significant aggregation is observed, if no pS-b-EP is used. The adsorption of pS-b-EP provides steric stabilization to the Pickering emulsion droplets, reduces aggregation significantly, and ultimately leads to the successful and efficient synthesis of pS microcapsules.

  12. Improving electrochromic properties via copolymerization

    NASA Astrophysics Data System (ADS)

    Tuba Taskin, Asli; Balan, Abidin; Arslan Udum, Yasemin; Toppare, Levent

    2010-06-01

    Copolymers of 5,8-di(1H-pyrrol-2-yl)-2,3-di(thiophen-2-yl)quinoxaline (PTQ) in the presence of 2, 2'-bis(3,4-ethylenedioxythiophene) (BiEDOT) and 4,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2-dodecyl-2H-benzo[1,2,3] triazole (BEBT) were synthesized via the potentiodynamic method in a tetrabutylammonium perchlorate/dichloromethane (TBAP/DCM) (0.1 M) solvent-electrolyte couple. P(PTQ-co-BiEDOT) reveals an oxidation potential at + 0.45 V and a reduction potential at - 0.2 V (figure 1(a)), whereas the homopolymer, P(PTQ) has an oxidation potential of + 0.55 V and a reduction potential of + 0.1 V. Spectroelectrochemical behaviors and the switching ability of copolymers were investigated by ultraviolet-visible (UV-vis) spectroscopy and cyclic voltammetry. The spectroelectrochemical behaviors of the P(PTQ-co-BiEDOT) and P(PTQ-co-BEBT) in comparison to the homopolymer revealed solid evidence of copolymerization based upon the differences in the spectral signatures. P(PTQ-co-BEBT) reveals 80% optical contrast at 1450 nm whereas the homopolymer achieves only 66% at 1460 nm. Coloration efficiency of P(PTQ-co-BEBT) was found to be 132 cm2 C - 1 compared to 116 cm2 C - 1 of the homopolymer at 100% full switch in the visible region. Switching times of the polymers were evaluated by kinetic studies upon measuring the per cent transmittance (%T) at the maximum contrast point. P(PTQ-co-BEBT) switches between the two extreme states in 0.5 s compared to 1.2 s for the homopolymer.

  13. 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

  14. Polylactide-based microspheres prepared using solid-state copolymerized chitosan and d,l-lactide.

    PubMed

    Demina, T S; Akopova, T A; Vladimirov, L V; Zelenetskii, A N; Markvicheva, E A; Grandfils, Ch

    2016-02-01

    Amphiphilic chitosan-g-poly(d,l-lactide) copolymers have been manufactured via solid-state mechanochemical copolymerization and tailored to design polyester-based microspheres for tissue engineering. A single-step solid-state reactive blending (SSRB) using low-temperature co-extrusion has been used to prepare these copolymers. These materials have been valorized to stabilize microspheres processed by an oil/water emulsion evaporation technique. Introduction of the copolymers either in water or in the oil phase of the emulsion allowed to replace a non-degradable emulsifier typically used for microparticle preparation. To enhance cell adhesion, these copolymers were also tailored to bring amino-saccharide positively charged segments to the microbead surface. Size distribution, surface morphology, and total microparticle yield have been studied and optimized as a function of the copolymer composition. PMID:26652381

  15. Polylactide-based microspheres prepared using solid-state copolymerized chitosan and d,l-lactide.

    PubMed

    Demina, T S; Akopova, T A; Vladimirov, L V; Zelenetskii, A N; Markvicheva, E A; Grandfils, Ch

    2016-02-01

    Amphiphilic chitosan-g-poly(d,l-lactide) copolymers have been manufactured via solid-state mechanochemical copolymerization and tailored to design polyester-based microspheres for tissue engineering. A single-step solid-state reactive blending (SSRB) using low-temperature co-extrusion has been used to prepare these copolymers. These materials have been valorized to stabilize microspheres processed by an oil/water emulsion evaporation technique. Introduction of the copolymers either in water or in the oil phase of the emulsion allowed to replace a non-degradable emulsifier typically used for microparticle preparation. To enhance cell adhesion, these copolymers were also tailored to bring amino-saccharide positively charged segments to the microbead surface. Size distribution, surface morphology, and total microparticle yield have been studied and optimized as a function of the copolymer composition.

  16. 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.

  17. Treating oilfield emulsions

    SciTech Connect

    Not Available

    1990-01-01

    This book is divided into the following sections: The Treating Problem of Oilfield Emulsion; The Theory of Emulsions; Emulsions and Production Practices; The Basic Principles of Treating; The Application of Heat in Treating; The Principles of Chemical Treating; Treating with Heater-Treaters; Automatic Central Oil-Treating Systems; Sampling Procedures; Testing for Sediment and Water; Treating Cost Records.

  18. High temperature structural, polymeric foams from high internal emulsion polymerization

    SciTech Connect

    Hoisington, M.A.; Duke, J.R.; Apen, P.G.

    1996-02-01

    In 1982, a high internal phase emulsion (HIPE) polymerization process to manufacture microcellular, polymeric foam systems was patented by Unilever. This patent discloses a polymerization process that occurs in a water-in-oil emulsion in which the water represents at least 76% of the emulsion by volume. The oil phase consists of vinyl monomers such as styrene and acrylates that are crosslinked by divinyl monomers during polymerization. After polymerization and drying to remove the water phase, the result is a crosslinked polymer foam with an open cell microstructure that is homogeneous throughout in terms of morphology, density, and mechanical properties. Since 1982, numerous patents have examined various HIPE polymerized foam processing techniques and applications that include absorbents for body fluids, cleaning materials, and ion exchange systems. All the published HIPE polymerized foams have concentrated on materials for low temperature applications. Copolymerization of styrene with maleic anhydride and N-substituted maleimides to produce heat resistant thermoplastics has been studied extensively. These investigations have shown that styrene will free radically copolymerize with N-substituted maleimides to create an alternating thermoplastic copolymer with a Tg of approximately 200{degrees}C. However, there are many difficulties in attempting the maleimide styrene copolymerization in a HIPE such as lower polymerization temperatures, maleimide solubility difficulties in both styrene and water, and difficulty obtaining a stable HIPE with a styrene/maleimide oil phase. This work describes the preparation of copolymer foams from N-ethylmaleimide and Bis(3-ethyl-5-methyl-4-maleimide-phenyl)methane with styrene based monomers and crosslinking agents.

  19. Direct Copolymerization of CO2 and Diols.

    PubMed

    Tamura, Masazumi; Ito, Kazuki; Honda, Masayoshi; Nakagawa, Yoshinao; Sugimoto, Hiroshi; Tomishige, Keiichi

    2016-01-01

    Direct polymerization of CO2 and diols is promising as a simple and environmental-benign method in place of conventional processes using high-cost and/or hazardous reagents such as phosgene, carbon monoxide and epoxides, however, there are no reports on the direct method due to the inertness of CO2 and severe equilibrium limitation of the reaction. Herein, we firstly substantiate the direct copolymerization of CO2 and diols using CeO2 catalyst and 2-cyanopyridine promotor, providing the alternating cooligomers in high diol-based yield (up to 99%) and selectivity (up to >99%). This catalyst system is applicable to various diols including linear C4-C10 α,ω-diols to provide high yields of the corresponding cooligomers, which cannot be obtained by well-known methods such as copolymerization of CO2 and cyclic ethers and ring-opening polymerization of cyclic carbonates. This process provides us a facile synthesis method for versatile polycarbonates from various diols and CO2 owing to simplicity of diols modification. PMID:27075987

  20. Direct Copolymerization of CO2 and Diols

    PubMed Central

    Tamura, Masazumi; Ito, Kazuki; Honda, Masayoshi; Nakagawa, Yoshinao; Sugimoto, Hiroshi; Tomishige, Keiichi

    2016-01-01

    Direct polymerization of CO2 and diols is promising as a simple and environmental-benign method in place of conventional processes using high-cost and/or hazardous reagents such as phosgene, carbon monoxide and epoxides, however, there are no reports on the direct method due to the inertness of CO2 and severe equilibrium limitation of the reaction. Herein, we firstly substantiate the direct copolymerization of CO2 and diols using CeO2 catalyst and 2-cyanopyridine promotor, providing the alternating cooligomers in high diol-based yield (up to 99%) and selectivity (up to >99%). This catalyst system is applicable to various diols including linear C4-C10 α,ω-diols to provide high yields of the corresponding cooligomers, which cannot be obtained by well-known methods such as copolymerization of CO2 and cyclic ethers and ring-opening polymerization of cyclic carbonates. This process provides us a facile synthesis method for versatile polycarbonates from various diols and CO2 owing to simplicity of diols modification. PMID:27075987

  1. Porating anion-responsive copolymeric gels.

    PubMed

    England, Dustin; Yan, Feng; Texter, John

    2013-09-24

    A polymerizable ionic liquid surfactant, 1-(11-acryloyloxyundecyl)-3-methylimidiazolium bromide (ILBr), was copolymerized with methyl methacrylate (MMA) in aqueous microemulsions at 30% (ILBr w/w) and various water to MMA ratios. The ternary phase diagram of the ILBr/MMA/water system was constructed at 25 and 60 °C. Homopolymers and copolymers of ILBr and MMA were produced by thermally initiated chain radical microemulsion polymerization at various compositions in bicontinuous and reverse microemulsion subdomains. Microemulsion polymerization reaction products varied from being gel-like to solid, and these materials were analyzed by thermal and scanning electron microscopy methods. Microemulsion polymerized materials were insoluble in all solvents tested, consistent with light cross-linking. Ion exchange between Br(-) and PF6(-) in these copolymeric materials resulted in the formation of open-cell porous structures in some of these materials, as was confirmed by scanning electron microscopy (SEM). Several compositions illustrate the capture of prepolymerization nanoscale structure by thermally initiated polymerization, expanding the domain of compositions exhibiting this feat and yet to be demonstrated in any other system. Regular cylindrical pores in interpenetrating ILBr-co-MMA and PMMA networks are produced by anion exchange in the absence of templates. A percolating cluster/bicontinuous transition is "captured" by SEM after using anion exchange to visualize the mixed cluster/pore morphology. Some design principles for achieving this capture and for obtaining stimuli responsive solvogels are articulated, and the importance of producing solvogels in capturing the nanoscale is highlighted. PMID:23968242

  2. Direct Copolymerization of CO2 and Diols

    NASA Astrophysics Data System (ADS)

    Tamura, Masazumi; Ito, Kazuki; Honda, Masayoshi; Nakagawa, Yoshinao; Sugimoto, Hiroshi; Tomishige, Keiichi

    2016-04-01

    Direct polymerization of CO2 and diols is promising as a simple and environmental-benign method in place of conventional processes using high-cost and/or hazardous reagents such as phosgene, carbon monoxide and epoxides, however, there are no reports on the direct method due to the inertness of CO2 and severe equilibrium limitation of the reaction. Herein, we firstly substantiate the direct copolymerization of CO2 and diols using CeO2 catalyst and 2-cyanopyridine promotor, providing the alternating cooligomers in high diol-based yield (up to 99%) and selectivity (up to >99%). This catalyst system is applicable to various diols including linear C4-C10 α,ω-diols to provide high yields of the corresponding cooligomers, which cannot be obtained by well-known methods such as copolymerization of CO2 and cyclic ethers and ring-opening polymerization of cyclic carbonates. This process provides us a facile synthesis method for versatile polycarbonates from various diols and CO2 owing to simplicity of diols modification.

  3. Oil emulsions of fluorosilicone fluids

    SciTech Connect

    Keil, J. W.

    1985-08-27

    Emulsions of fluorosilicone fluids in mineral oil are disclosed. These emulsions are stabilized by a polydimethylsiloxane-polybutadiene copolymer or a polydimethylsiloxane-hydrogenated polybutadiene copplymer. The emulsions are an effective foam suppressant for organic liquids, especially crude petroleum.

  4. Synthesis and characterization of brush-like multigraft copolymers PnBA-g-PMMA by a combination of emulsion AGET ATRP and emulsion polymerization.

    PubMed

    Li, Hui; Wang, Wenwen; Li, Chunmei; Tan, Jiaojun; Yin, Dezhong; Zhang, Hepeng; Zhang, Baoliang; Yin, Changjie; Zhang, Qiuyu

    2015-09-01

    In this paper, poly(n-butyl acrylate)-g-poly(methyl methacrylate) multigraft copolymers were synthesized by macromonomer technique and miniemulsion copolymerization. The PMMA macromonomers were obtained by an activator generated by electron transfer atom transfer radical polymerization (AGET ATRP) in emulsion system and subsequent allylation. Then the copolymerization of different macromonomers with nBA was carried out in miniemulsion system, obtaining multigraft copolymers with high molecular weight. The latex particles and distribution of emulsion AGET ATRP and miniemulsion copolymerization were characterized using laser light scattering. The molecular weight and polydispersity indices of macromonomers and multigraft copolymers were analyzed by gel permeation chromatography, and the number-average molecular weight range is 187,600-554,800 g/mol for PnBA-g-PMMA copolymers. In addition, the structural characteristics of macromonomer and brush-like copolymers were determined by infrared spectra and (1)H nuclear magnetic resonance spectroscopy. The thermal performance of brush-like copolymers were characterized by differential scanning calorimetry and thermogravimetric analysis. Atomic force microscopy results showed that the degree of microphase separation was varying with increasing PMMA content in PnBA-g-PMMA. The dynamic rheometer analysis revealed that multigraft copolymer with PMMA content of 31.4% exhibited good elastomeric properties to function as a TPE. These multigraft copolymers show a promising low cost and environmental friendly thermoplastic elastomer.

  5. Cationic bituminous emulsions and emulsion aggregate slurries

    SciTech Connect

    Schilling, P.

    1986-07-01

    A cationic bituminous emulsion is described which consists of from about 30% to about 80% by weight of bitumen, from about 0.1% to about 10% by weight of an emulsifier selected from the group consisting of reaction products of a polyamine reacted with a member of the group consisting of epoxidized unsaturated fatty acids of chain lengths between C/sub 8/ and C/sub 22/ and the esters thereof and adding water to make up 100% by weight, the emulsion having a pH in the range of from 2-7.

  6. Magnetoresistive emulsion analyzer.

    PubMed

    Lin, Gungun; Baraban, Larysa; Han, Luyang; Karnaushenko, Daniil; Makarov, Denys; Cuniberti, Gianaurelio; Schmidt, Oliver G

    2013-01-01

    We realize a magnetoresistive emulsion analyzer capable of detection, multiparametric analysis and sorting of ferrofluid-containing nanoliter-droplets. The operation of the device in a cytometric mode provides high throughput and quantitative information about the dimensions and magnetic content of the emulsion. Our method offers important complementarity to conventional optical approaches involving ferrofluids, and paves the way to the development of novel compact tools for diagnostics and nanomedicine including drug design and screening. PMID:23989504

  7. Magnetoresistive Emulsion Analyzer

    PubMed Central

    Lin, Gungun; Baraban, Larysa; Han, Luyang; Karnaushenko, Daniil; Makarov, Denys; Cuniberti, Gianaurelio; Schmidt, Oliver G.

    2013-01-01

    We realize a magnetoresistive emulsion analyzer capable of detection, multiparametric analysis and sorting of ferrofluid-containing nanoliter-droplets. The operation of the device in a cytometric mode provides high throughput and quantitative information about the dimensions and magnetic content of the emulsion. Our method offers important complementarity to conventional optical approaches involving ferrofluids, and paves the way to the development of novel compact tools for diagnostics and nanomedicine including drug design and screening. PMID:23989504

  8. Tuning the critical solution temperature of polymers by copolymerization

    SciTech Connect

    Schulz, Bernhard; Chudoba, Richard; Dzubiella, Joachim; Heyda, Jan

    2015-12-28

    We study statistical copolymerization effects on the upper critical solution temperature (CST) of generic homopolymers by means of coarse-grained Langevin dynamics computer simulations and mean-field theory. Our systematic investigation reveals that the CST can change monotonically or non-monotonically with copolymerization, as observed in experimental studies, depending on the degree of non-additivity of the monomer (A-B) cross-interactions. The simulation findings are confirmed and qualitatively explained by a combination of a two-component Flory-de Gennes model for polymer collapse and a simple thermodynamic expansion approach. Our findings provide some rationale behind the effects of copolymerization and may be helpful for tuning CST behavior of polymers in soft material design.

  9. Catalysts for CO2/epoxide ring-opening copolymerization

    PubMed Central

    Trott, G.; Saini, P. K.; Williams, C. K.

    2016-01-01

    This article summarizes and reviews recent progress in the development of catalysts for the ring-opening copolymerization of carbon dioxide and epoxides. The copolymerization is an interesting method to add value to carbon dioxide, including from waste sources, and to reduce pollution associated with commodity polymer manufacture. The selection of the catalyst is of critical importance to control the composition, properties and applications of the resultant polymers. This review highlights and exemplifies some key recent findings and hypotheses, in particular using examples drawn from our own research. PMID:26755758

  10. Copolymerization of carbon dioxide and butadiene via a lactone intermediate.

    PubMed

    Nakano, Ryo; Ito, Shingo; Nozaki, Kyoko

    2014-04-01

    Although carbon dioxide has attracted broad interest as a renewable carbon feedstock, its use as a monomer in copolymerization with olefins has long been an elusive endeavour. A major obstacle for this process is that the propagation step involving carbon dioxide is endothermic; typically, attempted reactions between carbon dioxide and an olefin preferentially yield olefin homopolymerization. Here we report a strategy to circumvent the thermodynamic and kinetic barriers for copolymerizations of carbon dioxide and olefins by using a metastable lactone intermediate, 3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one, which is formed by the palladium-catalysed condensation of carbon dioxide and 1,3-butadiene. Subsequent free-radical polymerization of the lactone intermediate afforded polymers of high molecular weight with a carbon dioxide content of 33 mol% (29 wt%). Furthermore, the protocol was applied successfully to a one-pot copolymerization of carbon dioxide and 1,3-butadiene, and one-pot terpolymerizations of carbon dioxide, butadiene and another 1,3-diene. This copolymerization technique provides access to a new class of polymeric materials made from carbon dioxide.

  11. Emulsions for interfacial filtration.

    SciTech Connect

    Grillet, Anne Mary; Bourdon, Christopher Jay; Souza, Caroline Ann; Welk, Margaret Ellen; Hartenberger, Joel David; Brooks, Carlton, F.

    2006-11-01

    We have investigated a novel emulsion interfacial filter that is applicable for a wide range of materials, from nano-particles to cells and bacteria. This technology uses the interface between the two immiscible phases as the active surface area for adsorption of targeted materials. We showed that emulsion interfaces can effectively collect and trap materials from aqueous solution. We tested two aqueous systems, a bovine serum albumin (BSA) solution and coal bed methane produced water (CBMPW). Using a pendant drop technique to monitor the interfacial tension, we demonstrated that materials in both samples were adsorbed to the liquid-liquid interface, and did not readily desorb. A prototype system was built to test the emulsion interfacial filter concept. For the BSA system, a protein assay showed a progressive decrease in the residual BSA concentration as the sample was processed. Based on the initial prototype operation, we propose an improved system design.

  12. 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.

  13. Recent advances in photoinduced donor/acceptor copolymerization

    NASA Astrophysics Data System (ADS)

    Jönsson, S.; Viswanathan, K.; Hoyle, C. E.; Clark, S. C.; Miller, C.; Morel, F.; Decker, C.

    1999-05-01

    Photoinitiated free radical polymerization of donor (D)/acceptor (A) type monomers has gained considerable interest due to the possibility to efficiently photopolymerize non-acrylate based systems. Furthermore, this photoinduced alternating copolymerization can be accomplished without the presence of a conventional free radical generating photoinitiator. In the past, we have shown that the structural influences in the direct photolysis of N-Alkyl and N-Arylmaleimides as well as their corresponding ground state charge transfer complexes (CTC) with suitable donors have carefully been investigated. For certain combinations of A and D type monomers, a direct photolysis of the ground state complex or the excitation of the acceptor, followed by the formation of an exciplex, has been shown to initiate the copolymerization. Herein, we show that the main route of initiation is based on inter or intra molecular H-abstraction from an excited state maleimide, whereby no exciplex formation takes place. H-abstraction will predominantly take place in systems where easily abstractable hydrogens are present. Our laser flash photolysis investigation, ESR [1] (A. Hiroshi, I. Takasi, T. Nosi, Macromol. Chem. 190 (1989) 2821) and phosphorescence emissions [2,3] (K.S. Chen, T. Foster, J.K.S. Wan, J. Phys. Chem. 84 (1980) 2473; C.J. Seliskar, S.P. McGlynn, J. Chem. Phys. 55 (1971) 4337) studies show that triplet excited states of N-alkyl substituted maleimides (RMI), which are well known strong precursors for direct H-abstractions from aliphatic ethers and secondary alcohols, are formed upon excitation. Rates of copolymerization and degrees of conversion for copolymerization of maleimide/vinyl ether pairs in air and nitrogen have been measured as a function of hydrogen abstractability of the excited triplet state MI as well as the influence of concentration and hydrogen donating effect of the hydrogen donor.

  14. Double Emulsion Templated Celloidosomes

    NASA Astrophysics Data System (ADS)

    Arriaga, Laura R.; Marquez, Samantha M.; Kim, Shin-Hyun; Chang, Connie; Wilking, Jim; Monroy, Francisco; Marquez, Manuel; Weitz, David A.

    2012-02-01

    We present a novel approach for fabricating celloidosomes, which represent a hollow and spherical three-dimensional self-assembly of living cells encapsulating an aqueous core. Glass- capillary microfluidics is used to generate monodisperse water-in-oil-in-water double emulsion templates using lipids as stabilizers. Such templates allow for obtaining single but also double concentric celloidosomes. In addition, after a solvent removal step the double emulsion templates turn into monodisperse lipid vesicles, whose membrane spontaneously phase separates when choosing the adequate lipid composition, providing the adequate scaffold for fabricating Janus-celloidosomes. These structures may find applications in the development of bioreactors in which the synergistic effects of two different types of cells selectively adsorbed on one of the vesicle hemispheres may be exploited.

  15. FINE GRAIN NUCLEAR EMULSION

    DOEpatents

    Oliver, A.J.

    1962-04-24

    A method of preparing nuclear track emulsions having mean grain sizes less than 0.1 microns is described. The method comprises adding silver nitrate to potassium bromide at a rate at which there is always a constant, critical excess of silver ions. For minimum size grains, the silver ion concentration is maintained at the critical level of about pAg 2.0 to 5.0 during prectpitation, pAg being defined as the negative logarithm of the silver ion concentration. It is preferred to eliminate the excess silver at the conclusion of the precipitation steps. The emulsion is processed by methods in all other respects generally similar to the methods of the prior art. (AEC)

  16. Pickering emulsion templated interfacial atom transfer radical polymerization for microencapsulation.

    PubMed

    Li, Jian; Hitchcock, Adam P; Stöver, Harald D H

    2010-12-01

    This Article describes a new microencapsulation method based on a Pickering emulsion templated interfacial atom transfer radical polymerization (PETI-ATRP). Cationic LUDOX CL nanoparticles were coated electrostatically with an anionic polymeric ATRP initiator, poly(sodium styrene sulfonate-co-2-(2-bromoisobutyryloxy)ethyl methacrylate) (PSB), prepared by radical copolymerization of sodium styrene sulfonate and 2-(2-bromoisobutyryloxy)ethyl methacrylate (BIEM). The resulting PSB-modified CL particles were surface active and could be used to stabilize oil-in-water Pickering emulsions. ATRP of water-soluble cross-linking monomers, confined to the oil-water interface by the surface-bound PSB, then led to nanoparticle/polymer composite shells. This method allowed encapsulation of core solvents (xylene, hexadecane, perfluoroheptane) with different solubility parameters. The microcapsule (MC) wall chemistry could accommodate different monomers, demonstrating the versatility of this method. Double-walled MCs were formed by sequentially carrying out PETI-ATRP and in situ polymerization of encapsulated monomers. The double-walled structure was verified by both transmission electron microscopy (TEM) and scanning transmission X-ray microscopy (STXM).

  17. Pickering emulsions with controllable stability.

    PubMed

    Melle, Sonia; Lask, Mauricio; Fuller, Gerald G

    2005-03-15

    We prepare solid-stabilized emulsions using paramagnetic particles at an oil/water interface that can undergo macroscopic phase separation upon application of an external magnetic field. A critical field strength is found for which emulsion droplets begin to translate into the continuous-phase fluid. At higher fields, the emulsions destabilize, leading to a fully phase-separated system. This effect is reversible, and long-term stability can be recovered by remixing the components with mechanical agitation. PMID:15752002

  18. Cyclodextrin stabilised emulsions and cyclodextrinosomes.

    PubMed

    Mathapa, Baghali G; Paunov, Vesselin N

    2013-11-01

    We report the preparation of o/w emulsions stabilised by microcrystals of cyclodextrin-oil inclusion complexes. The inclusion complexes are formed by threading cyclodextrins from the aqueous phase on n-tetradecane or silicone oil molecules from the emulsion drop surface which grow further into microrods and microplatelets depending on the type of cyclodextrin (CD) used. These microcrystals remain attached on the surface of the emulsion drops and form densely packed layers which resemble Pickering emulsions. The novelty of this emulsion stabilisation mechanism is that molecularly dissolved cyclodextrin from the continuous aqueous phase is assembled into colloid particles directly onto the emulsion drop surface, i.e. molecular adsorption leads to effective Pickering stabilisation. The β-CD stabilised tetradecane-in-water emulsions were so stable that we used this system as a template for preparation of cyclodextrinosomes. These structures were produced solely through formation of cyclodextrin-oil inclusion complexes and their assembly into a crystalline phase on the drop surface retained its stability after the removal of the core oil. The structures of CD-stabilised tetradecane-in-water emulsions were characterised using optical microscopy, fluorescence microscopy, cross-polarised light microscopy and WETSEM while the cyclodextrinosomes were characterised by SEM. We also report the preparation of CD-stabilised emulsions with a range of other oils, including tricaprylin, silicone oil, isopropyl myristate and sunflower oil. We studied the effect of the salt concentration in the aqueous phase, the type of CD and the oil volume fraction on the type of emulsion formed. The CD-stabilised emulsions can be applied in a range of surfactant-free formulations with possible applications in cosmetics, home and personal care. Cyclodextrinosomes could find applications in pharmaceutical formulations as microencapsulation and drug delivery vehicles. PMID:24043288

  19. Rubberized asphalt emulsion

    SciTech Connect

    Wilkes, E.

    1986-09-02

    A method is described of making a rubberized asphalt composition which comprises the steps of: (a) combining asphalt with a hydrocarbon oil having a flash point of 300/sup 0/F. or more to provide a homogenous asphalt-oil mixture or solution, (b) then combining the asphalt-oil mixture with a particulate rubber at a temperature sufficient to provide a homogenous asphalt-rubber-oil gel, and (c) emulsifying the asphalt-rubber-oil gel by passing the gel, water, and an emulsifying agent through a colloid mill to provide an emulsion.

  20. Chain Copolymerization Reactions: An Algorithm to Predict the Reaction Evolution with Conversion

    ERIC Educational Resources Information Center

    Gallardo, Alberto; Aguilar, Maria Rosa; Abraham, Gustavo A.; Roman, Julio San

    2004-01-01

    An algorithm is developed to study and understand the behavior of chain copolymerization reactions. When a binary copolymerization reaction follows the terminal model, Conversion is able to predict the evolution of different parameters, such as instantaneous and cumulative copolymer molar fractions, or molar fractions of any sequence with the…

  1. Programmed emulsions for sodium reduction in emulsion based foods.

    PubMed

    Chiu, Natalie; Hewson, Louise; Fisk, Ian; Wolf, Bettina

    2015-05-01

    In this research a microstructure approach to reduce sodium levels in emulsion based foods is presented. If successful, this strategy will enable reduction of sodium without affecting consumer satisfaction with regard to salty taste. The microstructure approach comprised of entrapment of sodium in the internal aqueous phase of water-in-oil-in-water emulsions. These were designed to destabilise during oral processing when in contact with the salivary enzyme amylase in combination with the mechanical manipulation of the emulsion between the tongue and palate. Oral destabilisation was achieved through breakdown of the emulsion that was stabilised with a commercially modified octenyl succinic anhydride (OSA)-starch. Microstructure breakdown and salt release was evaluated utilising in vitro, in vivo and sensory methods. For control emulsions, stabilised with orally inert proteins, no loss of structure and no release of sodium from the internal aqueous phase was found. The OSA-starch microstructure breakdown took the initial form of oil droplet coalescence. It is hypothesised that during this coalescence process sodium from the internalised aqueous phase is partially released and is therefore available for perception. Indeed, programmed emulsions showed an enhancement in saltiness perception; a 23.7% reduction in sodium could be achieved without compromise in salty taste (p < 0.05; 120 consumers). This study shows a promising new approach for sodium reduction in liquid and semi-liquid emulsion based foods. PMID:25865459

  2. Programmed emulsions for sodium reduction in emulsion based foods.

    PubMed

    Chiu, Natalie; Hewson, Louise; Fisk, Ian; Wolf, Bettina

    2015-05-01

    In this research a microstructure approach to reduce sodium levels in emulsion based foods is presented. If successful, this strategy will enable reduction of sodium without affecting consumer satisfaction with regard to salty taste. The microstructure approach comprised of entrapment of sodium in the internal aqueous phase of water-in-oil-in-water emulsions. These were designed to destabilise during oral processing when in contact with the salivary enzyme amylase in combination with the mechanical manipulation of the emulsion between the tongue and palate. Oral destabilisation was achieved through breakdown of the emulsion that was stabilised with a commercially modified octenyl succinic anhydride (OSA)-starch. Microstructure breakdown and salt release was evaluated utilising in vitro, in vivo and sensory methods. For control emulsions, stabilised with orally inert proteins, no loss of structure and no release of sodium from the internal aqueous phase was found. The OSA-starch microstructure breakdown took the initial form of oil droplet coalescence. It is hypothesised that during this coalescence process sodium from the internalised aqueous phase is partially released and is therefore available for perception. Indeed, programmed emulsions showed an enhancement in saltiness perception; a 23.7% reduction in sodium could be achieved without compromise in salty taste (p < 0.05; 120 consumers). This study shows a promising new approach for sodium reduction in liquid and semi-liquid emulsion based foods.

  3. Rheology of hydrate forming emulsions.

    PubMed

    Peixinho, Jorge; Karanjkar, Prasad U; Lee, Jae W; Morris, Jeffrey F

    2010-07-20

    Results are reported on an experimental study of the rheology of hydrate-forming water-in-oil emulsions. Density-matched concentrated emulsions were quenched by reducing the temperature and an irreversible transition was observed where the viscosity increased dramatically. The hydrate-forming emulsions have characteristic times for abrupt viscosity change dependent only on the temperature, reflecting the importance of the effect of subcooling. Mechanical transition of hydrate-free water-in-oil emulsions may require longer times and depends on the shear rate, occurring more rapidly at higher rates but with significant scatter which is characterized through a probabilistic analysis. This rate dependence together with dependence on subcooling reflects the importance of hydrodynamic forces to bring drops or particles together.

  4. Hyperbranched PEG by random copolymerization of ethylene oxide and glycidol.

    PubMed

    Wilms, Daniel; Schömer, Martina; Wurm, Frederik; Hermanns, M Iris; Kirkpatrick, C James; Frey, Holger

    2010-10-18

    The synthesis of hyperbranched poly(ethylene glycol) (hbPEG) in one step was realized by random copolymerization of ethylene oxide and glycidol, leading to a biocompatible, amorphous material with multiple hydroxyl functionalities. A series of copolymers with moderate polydispersity ($\\overline {M} _{{\\rm w}} /\\overline {M} _{{\\rm n}} $ < 1.8) was obtained with varying glycidol content (3-40 mol-%) and molecular weights up to 49 800 g mol(-1) . The randomly branched structure of the copolymers was confirmed by (1) H and (13) C NMR spectroscopy and thermal analysis (differential scanning calorimetry). MTS assay demonstrated low cell toxicity of the hyperbranched PEG, comparable to the highly established linear PEG.

  5. Radiation initiated copolymerization of allyl alcohol with acrylonitrile

    NASA Astrophysics Data System (ADS)

    Şolpan, Dilek; Güven, Olgun

    1996-07-01

    Copolymerization of allyl alcohol (AA) with acrylonitrile (AN) initiated by γ-rays has been investigated to determine the respective reactivity ratios. Three different experimental techniques, namely Fourier Transform Infrared (FTIR), Ultraviolet (UV/vis) and elemental analysis (EA) have been used for the determination of copolymer compositions. Fineman-Ross (FR), Kelen-Tüdös (KT), Non-Linear Least Square (NLLS) Analysis and Q-e methods have been applied to the three sets of experimental data. It has been concluded that data obtained from elemental analysis as applied to the Non-Linear Least Square approach gave the most reliable reactivity ratios as 2.09 and 0.40 for acrylonitrile and allyl alcohol, respectively.

  6. Cationic resins prepared by radiation-induced graft copolymerization

    NASA Astrophysics Data System (ADS)

    Siyam, T.; Youssef, H. A.

    1999-07-01

    Poly(acrylamide-acrylic acid) resin P(PAM-AA) was prepared by gamma radiation-initiated grafting copolymerization of acrylic acid (AA) on polyacrylamide (PAM) by addition of Mohr's salt as an inhibitor for homopolymerization. The polymerization was studied at different absorbed doses, polymor/monomer ratios and the monomer concentrations. The grafting percentage increases by increasing the dose and the monomer concentration and decreases by increasing polymer/monomer ratio. There is no significant change in the swelling degree of the obtained resin. It was found that the capacity of the resins towards Cu 2+ increases with increasing the monomer concentration and decreases by increasing the polymer/monomer ratio. The capacity of the resin was found to be constant at all doses.

  7. Kinetics and thermodynamics of first-order Markov chain copolymerization

    SciTech Connect

    Gaspard, P.; Andrieux, D.

    2014-07-28

    We report a theoretical study of stochastic processes modeling the growth of first-order Markov copolymers, as well as the reversed reaction of depolymerization. These processes are ruled by kinetic equations describing both the attachment and detachment of monomers. Exact solutions are obtained for these kinetic equations in the steady regimes of multicomponent copolymerization and depolymerization. Thermodynamic equilibrium is identified as the state at which the growth velocity is vanishing on average and where detailed balance is satisfied. Away from equilibrium, the analytical expression of the thermodynamic entropy production is deduced in terms of the Shannon disorder per monomer in the copolymer sequence. The Mayo-Lewis equation is recovered in the fully irreversible growth regime. The theory also applies to Bernoullian chains in the case where the attachment and detachment rates only depend on the reacting monomer.

  8. Highly CO2/N2-switchable zwitterionic surfactant for pickering emulsions at ambient temperature.

    PubMed

    Liu, Pingwei; Lu, Weiqiang; Wang, Wen-Jun; Li, Bo-Geng; Zhu, Shiping

    2014-09-01

    Cross-linked polymer particles were prepared via surfactant-free emulsion copolymerization of 2-(diethylamino)ethyl methacrylate (DEAEMA) and sodium methacrylate (SMA) using N,N'-methylenebis(acrylamide) (MBA) as a cross-linker. Generated particles are zwitterionic, possessing unique isoelectric points in the pH range of 7.5-8.0, which is readily tunable through CO2/N2 bubbling. The particles were found to be highly responsive to CO2/N2 switching, dissolving in water with CO2 bubbling and precipitating with N2 bubbling at room temperature. Pickering emulsions of n-dodecane were prepared using these particles as the sole emulsifier. These emulsions can be rapidly demulsified with CO2 bubbling, resulting in complete oil/water phase separations. Nitrogen bubbling efficiently re-emulsifies the oil with the aid of homogenization. The rapid emulsification/demulsification using CO2/N2 bubbling at room temperature provides these cross-linked zwitterionic particles with distinct advantages as functional Pickering surfactants.

  9. Intravascular behavior of a perfluorochemical emulsion.

    PubMed

    Tsuda, Y; Yamanouchi, K; Okamoto, H; Yokoyama, K; Heldebrant, C

    1990-03-01

    The purpose of this study was to clarify the reason why two similar perfluorochemical (PFC) emulsions, namely a mixed PFC (perfluorodecalin: FDC and perfluorotripropylamine: FTPA) and an FDC emulsion, resulted in a very different survival time for the exchange-transfused rats. Supposing that some difference in the intravascular behavior of both emulsions would account for such a difference in efficacy, experiments on behavior of PFC emulsions were carried out focusing on the particle size. It was reconfirmed that larger PFC particles were eliminated from the blood stream much more rapidly than smaller particles with three FMIQ (perfluoro-N-methyldecahydroisoquinoline) emulsions. After the FDC + FTPA emulsion or the FDC emulsion were injected into rabbits, PFC particles in the blood tended to decrease in size. When each of the collected blood samples was incubated at 37 degrees C for 24 h, the FDC emulsion enlarged in size markedly, but the FDC + FTPA emulsion showed no change. The retention of PFC particles appeared to depend on the emulsion stability rather than simply on the emulsifying agent alone. These data showed that some differences were observed in intravascular persistence of the FDC + FTPA emulsion and the FDC emulsion, and suggested that the efficacy of PFC emulsions would reflect their behavior in the circulation. PMID:2374085

  10. Optimizing organoclay stabilized Pickering emulsions.

    PubMed

    Cui, Yannan; Threlfall, Mhairi; van Duijneveldt, Jeroen S

    2011-04-15

    Oil-in-water emulsions were prepared using montmorillonite clay platelets, pre-treated with quaternary amine surfactants. In previous work, cetyl trimethylammonium bromide (CTAB) has been used. In this study, two more hydrophilic quaternary amine surfactants, Berol R648 and Ethoquad C/12, were used and formed Pickering emulsions, which were more stable than the emulsions prepared using CTAB coated clay. The droplets were also more mono-disperse. The most hydrophilic surfactant Berol R648 stabilizes the emulsions best. Salt also plays an important role in forming a stable emulsion. The droplet size decreases with surfactant concentration and relatively mono-disperse droplets can be obtained at moderate surfactant concentrations. The time evolution of the droplet size indicates a good stability to coalescence in the presence of Berol R648. Using polarizing microscopy, the clay platelets were found to be lying flat at the water oil interface. However, a significant fraction (about 90%) of clay stayed in the water phase and the clay particles at the water-oil interface formed stacks, each consisting of four clay platelets on average.

  11. The effect of oil components on the physicochemical properties and drug delivery of emulsions: tocol emulsion versus lipid emulsion.

    PubMed

    Hung, Chi-Feng; Fang, Chia-Lang; Liao, Mei-Hui; Fang, Jia-You

    2007-04-20

    An emulsion system composed of vitamin E, coconut oil, soybean phosphatidylcholine, non-ionic surfactants, and polyethylene glycol (PEG) derivatives (referred to as the tocol emulsion) was characterized in terms of its physicochemical properties, drug release, in vivo efficacy, toxicity, and stability. Systems without vitamin E (referred to as the lipid emulsion) and without any oils (referred to as the aqueous micelle system) were prepared for comparison. A lipophilic antioxidant, resveratrol, was used as the model drug for emulsion loading. The incorporation of Brij 35 and PEG derivatives reduced the vesicle diameter to <100nm. The inclusion of resveratrol into the emulsions and aqueous micelles retarded the drug release. The in vitro release rate showed a decrease in the order of aqueous micelle system>tocol emulsion>lipid emulsion. Treatment of resveratrol dramatically reduced the intimal hyperplasia of the injured vascular wall in rats. There was no significant difference in this reduction when resveratrol was delivered by either emulsion or the aqueous micelle system. The percentages of erythrocyte hemolysis by the emulsions and aqueous micelle system were approximately 0 and approximately 10%, respectively. Vitamin E prevented the aggregation of emulsion vesicles. The mean vesicle size of the tocol emulsion remained unchanged during 30 days at 37 degrees C. The lipid emulsion and aqueous micelle system, respectively, showed 11- and 16-fold increases in vesicle size after 30 days of storage.

  12. Advances with holographic DESA emulsions

    NASA Astrophysics Data System (ADS)

    Dünkel, Lothar; Eichler, Jürgen; Schneeweiss, Claudia; Ackermann, Gerhard

    2006-02-01

    DESA emulsions represent layer systems based on ultra-fine grained silver halide (AgX) technology. The new layers have an excellent performance for holographic application. The technology has been presented repeatedly in recent years, including the emulsion characterization and topics of chemical and spectral sensitization. The paper gives a survey of actual results referring to panchromatic sensitization and other improvements like the application of silver halide sensitized gelatine (SHSG) procedure. These results are embedded into intensive collaborations with small and medium enterprises (SME's) to commercialize DESA layers. Predominant goals are innovative products with holographic components and layers providing as well as cost effectiveness and high quality.

  13. Fragmentation and Coagulation in Supramolecular (Co)polymerization Kinetics.

    PubMed

    Markvoort, Albert J; Eikelder, Huub M M Ten; Hilbers, Peter A J; de Greef, Tom F A

    2016-04-27

    The self-assembly of molecular building blocks into one-dimensional supramolecular architectures has opened up new frontiers in materials science. Due to the noncovalent interactions between the monomeric units, these architectures are intrinsically dynamic, and understanding their kinetic driving forces is key to rationally programming their morphology and function. To understand the self-assembly dynamics of supramolecular polymerizations (SP), kinetic models based on aggregate growth by sequential monomer association and dissociation have been analyzed. However, fragmentation and coagulation events can also play a role, as evident from studies on peptide self-assembly and the fact that aggregations can be sensitive to mechanical agitations. Here, we analyze how fragmentation and coagulation events influence SP kinetics by theoretical analysis of self-assembling systems of increasing complexity. Our analysis starts with single-component systems in which aggregates are able to grow via an isodesmic or cooperative nucleation-elongation mechanism. Subsequently, equilibration dynamics in cooperative two-component supramolecular copolymerizations are investigated. In the final part, we reveal how aggregate growth in the presence of competing, kinetically controlled pathways is influenced by fragmentation and coagulation reactions and reveal how seed-induced growth can give rise to block copolymers. Our analysis shows how fragmentation and coagulation reactions are able to modulate SP kinetics in ways that are highly system dependent. PMID:27163054

  14. Fragmentation and Coagulation in Supramolecular (Co)polymerization Kinetics

    PubMed Central

    2016-01-01

    The self-assembly of molecular building blocks into one-dimensional supramolecular architectures has opened up new frontiers in materials science. Due to the noncovalent interactions between the monomeric units, these architectures are intrinsically dynamic, and understanding their kinetic driving forces is key to rationally programming their morphology and function. To understand the self-assembly dynamics of supramolecular polymerizations (SP), kinetic models based on aggregate growth by sequential monomer association and dissociation have been analyzed. However, fragmentation and coagulation events can also play a role, as evident from studies on peptide self-assembly and the fact that aggregations can be sensitive to mechanical agitations. Here, we analyze how fragmentation and coagulation events influence SP kinetics by theoretical analysis of self-assembling systems of increasing complexity. Our analysis starts with single-component systems in which aggregates are able to grow via an isodesmic or cooperative nucleation–elongation mechanism. Subsequently, equilibration dynamics in cooperative two-component supramolecular copolymerizations are investigated. In the final part, we reveal how aggregate growth in the presence of competing, kinetically controlled pathways is influenced by fragmentation and coagulation reactions and reveal how seed-induced growth can give rise to block copolymers. Our analysis shows how fragmentation and coagulation reactions are able to modulate SP kinetics in ways that are highly system dependent. PMID:27163054

  15. Emulsion Chamber Technology Experiment (ECT)

    NASA Technical Reports Server (NTRS)

    Gregory, John C.; Takahashi, Yoshiyuki

    1996-01-01

    The experimental objective of Emulsion Chamber Technology (ECT) was to develop space-borne emulsion chamber technology so that cosmic rays and nuclear interactions may subsequently be studied at extremely high energies with long exposures in space. A small emulsion chamber was built and flown on flight STS-62 of the Columbia in March 1994. Analysis of the several hundred layers of radiation-sensitive material has shown excellent post-flight condition and suitability for cosmic ray physics analysis at much longer exposures. Temperature control of the stack was 20 +/-1 C throughout the active control period and no significant deviations of temperature or pressure in the chamber were observed over the entire mission operations period. The unfortunate flight attitude of the orbiter (almost 90% Earth viewing) prevented any significant number of heavy particles (Z greater than or equal to 10) reaching the stack and the inverted flow of shower particles in the calorimeter has not allowed evaluation of absolute primary cosmic ray-detection efficiency nor of the practical time limits of useful exposure of these calorimeters in space to the level of detail originally planned. Nevertheless, analysis of the observed backgrounds and quality of the processed photographic and plastic materials after the flight show that productive exposures of emulsion chambers are feasible in low orbit for periods of up to one year or longer. The engineering approaches taken in the ECT program were proven effective and no major environmental obstacles to prolonged flight are evident.

  16. Controlling molecular transport in minimal emulsions

    PubMed Central

    Gruner, Philipp; Riechers, Birte; Semin, Benoît; Lim, Jiseok; Johnston, Abigail; Short, Kathleen; Baret, Jean-Christophe

    2016-01-01

    Emulsions are metastable dispersions in which molecular transport is a major mechanism driving the system towards its state of minimal energy. Determining the underlying mechanisms of molecular transport between droplets is challenging due to the complexity of a typical emulsion system. Here we introduce the concept of ‘minimal emulsions', which are controlled emulsions produced using microfluidic tools, simplifying an emulsion down to its minimal set of relevant parameters. We use these minimal emulsions to unravel the fundamentals of transport of small organic molecules in water-in-fluorinated-oil emulsions, a system of great interest for biotechnological applications. Our results are of practical relevance to guarantee a sustainable compartmentalization of compounds in droplet microreactors and to design new strategies for the dynamic control of droplet compositions. PMID:26797564

  17. Multiple pickering emulsions stabilized by microbowls.

    PubMed

    Nonomura, Yoshimune; Kobayashi, Naoto; Nakagawa, Naoki

    2011-04-19

    Some researchers have focused on the adsorption of solid particles at fluid-fluid interfaces and prepared emulsions and foams called "Pickering emulsions/foams". However, while several reports exist on simple spherical emulsions, few reports are available on the formation of more complex structures. Here, we show that holes on particle surfaces are a key factor in establishing the variety and complexity of mesoscale structures. Microbowls, which are hollow particles with holes on their surfaces, form multiple emulsions (water-in-oil-in-water and oil-in-water-in-oil emulsions) by simply mixing them with water and oil. Furthermore, stable potato-like or coffee-bean-like emulsions are also obtained, although nonspherical emulsions are usually unstable because of their larger interfacial energies. These findings are useful in designing the building blocks of complex supracolloidal systems for pharmaceutical, food, and cosmetic products.

  18. Controlling molecular transport in minimal emulsions

    NASA Astrophysics Data System (ADS)

    Gruner, Philipp; Riechers, Birte; Semin, Benoît; Lim, Jiseok; Johnston, Abigail; Short, Kathleen; Baret, Jean-Christophe

    2016-01-01

    Emulsions are metastable dispersions in which molecular transport is a major mechanism driving the system towards its state of minimal energy. Determining the underlying mechanisms of molecular transport between droplets is challenging due to the complexity of a typical emulsion system. Here we introduce the concept of `minimal emulsions', which are controlled emulsions produced using microfluidic tools, simplifying an emulsion down to its minimal set of relevant parameters. We use these minimal emulsions to unravel the fundamentals of transport of small organic molecules in water-in-fluorinated-oil emulsions, a system of great interest for biotechnological applications. Our results are of practical relevance to guarantee a sustainable compartmentalization of compounds in droplet microreactors and to design new strategies for the dynamic control of droplet compositions.

  19. The emulsion chamber technology experiment

    NASA Technical Reports Server (NTRS)

    Gregory, John C.

    1992-01-01

    Photographic emulsion has the unique property of recording tracks of ionizing particles with a spatial precision of 1 micron, while also being capable of deployment over detector areas of square meters or 10's of square meters. Detectors are passive, their cost to fly in Space is a fraction of that of instruments of similar collecting. A major problem in their continued use has been the labor intensiveness of data retrieval by traditional microscope methods. Two factors changing the acceptability of emulsion technology in space are the astronomical costs of flying large electronic instruments such as ionization calorimeters in Space, and the power and low cost of computers, a small revolution in the laboratory microscope data-taking. Our group at UAH made measurements of the high energy composition and spectra of cosmic rays. The Marshall group has also specialized in space radiation dosimetry. Ionization calorimeters, using alternating layers of lead and photographic emulsion, to measure particle energies up to 10(exp 15) eV were developed. Ten balloon flights were performed with them. No such calorimeters have ever flown in orbit. In the ECT program, a small emulsion chamber was developed and will be flown on the Shuttle mission OAST-2 to resolve the principal technological questions concerning space exposures. These include assessments of: (1) pre-flight and orbital exposure to background radiation, including both self-shielding and secondary particle generation; the practical limit to exposure time in space can then be determined; (2) dynamics of stack to optimize design for launch and weightlessness; and (3) thermal and vacuum constraints on emulsion performance. All these effects are cumulative and affect our ability to perform scientific measurements but cannot be adequately predicted by available methods.

  20. Reactivity ratios, and mechanistic insight for anionic ring-opening copolymerization of epoxides.

    PubMed

    Lee, Bongjae F; Wolffs, Martin; Delaney, Kris T; Sprafke, Johannes K; Leibfarth, Frank A; Hawker, Craig J; Lynd, Nathaniel A

    2012-05-01

    Reactivity ratios were evaluated for anionic ring-opening copolymerizations of ethylene oxide (EO) with either allyl glycidyl ether (AGE) or ethylene glycol vinyl glycidyl ether (EGVGE) using a benzyl alkoxide initiator. The chemical shift for the benzylic protons of the initiator, as measured by (1)H NMR spectroscopy, were observed to be sensitive to the sequence of the first two monomers added to the initiator during polymer growth. Using a simple kinetic model for initiation and the first propagation step, reactivity ratios for the copolymerization of AGE and EGVGE with EO could be determined by analysis of the (1)H NMR spectroscopy for the resulting copolymer. For the copolymerization between EO and AGE, the reactivity ratios were determined to be r(AGE) = 1.31 ± 0.26 and r(EO) = 0.54 ± 0.03, while for EO and EGVGE, the reactivity ratios were r(EGVGE) = 3.50 ± 0.90 and r(EO) = 0.32 ± 0.10. These ratios were consistent with the compositional drift observed in the copolymerization between EO and EGVGE, with EGVGE being consumed early in the copolymerization. These experimental results, combined with density functional calculations, allowed a mechanism for oxyanionic ring-opening polymerization that begins with coordination of the Lewis-basic epoxide to the cation to be proposed. The calculated transition-state energies agree qualitatively with the observed relative rates for polymerization. PMID:23226879

  1. Polymerization in emulsion microdroplet reactors

    NASA Astrophysics Data System (ADS)

    Carroll, Nick J.

    The goal of this research project is to utilize emulsion droplets as chemical reactors for execution of complex polymerization chemistries to develop unique and functional particle materials. Emulsions are dispersions of immiscible fluids where one fluid usually exists in the form of drops. Not surprisingly, if a liquid-to-solid chemical reaction proceeds to completion within these drops, the resultant solid particles will possess the shape and relative size distribution of the drops. The two immiscible liquid phases required for emulsion polymerization provide unique and complex chemical and physical environments suitable for the engineering of novel materials. The development of novel non-ionic fluorosurfactants allows fluorocarbon oils to be used as the continuous phase in a water-free emulsion. Such emulsions enable the encapsulation of almost any hydrocarbon compound in droplets that may be used as separate compartments for water-sensitive syntheses. Here, we exemplify the promise of this approach by suspension polymerization of polyurethanes (PU), in which the liquid precursor is emulsified into droplets that are then converted 1:1 into polymer particles. The stability of the droplets against coalescence upon removal of the continuous phase by evaporation confirms the formation of solid PU particles. These results prove that the water-free environment of fluorocarbon based emulsions enables high conversion. We produce monodisperse, cross-linked, and fluorescently labeled PU-latexes with controllable mesh size through microfluidic emulsification in a simple one-step process. A novel method for the fabrication of monodisperse mesoporous silica particles is presented. It is based on the formation of well-defined equally sized emulsion droplets using a microfluidic approach. The droplets contain the silica precursor/surfactant solution and are suspended in hexadecane as the continuous oil phase. The solvent is then expelled from the droplets, leading to

  2. Analysis of emulsion stability in acrylic dispersions

    NASA Astrophysics Data System (ADS)

    Ahuja, Suresh

    2012-02-01

    Emulsions either micro or nano permit transport or solubilization of hydrophobic substances within a water-based phase. Different methods have been introduced at laboratory and industrial scales: mechanical stirring, high-pressure homogenization, or ultrasonics. In digital imaging, toners may be formed by aggregating a colorant with a latex polymer formed by batch or semi-continuous emulsion polymerization. Latex emulsions are prepared by making a monomer emulsion with monomer like Beta-carboxy ethyl acrylate (β-CEA) and stirring at high speed with an anionic surfactant like branched sodium dodecyl benzene sulfonates , aqueous solution until an emulsion is formed. Initiator for emulsion polymerization is 2-2'- azobis isobutyramide dehydrate with chain transfer agent are used to make the latex. If the latex emulsion is unstable, the resulting latexes produce a toner with larger particle size, broader particle size distribution with relatively higher latex sedimentation, and broader molecular weight distribution. Oswald ripening and coalescence cause droplet size to increase and can result in destabilization of emulsions. Shear thinning and elasticity of emulsions are applied to determine emulsion stability.

  3. Steroidal Compounds in Commercial Parenteral Lipid Emulsions

    PubMed Central

    Xu, Zhidong; Harvey, Kevin A.; Pavlina, Thomas; Dutot, Guy; Hise, Mary; Zaloga, Gary P.; Siddiqui, Rafat A.

    2012-01-01

    Parenteral nutrition lipid emulsions made from various plant oils contain steroidal compounds, called phytosterols. During parenteral administration of lipid emulsions, phytosterols can reach levels in the blood that are many fold higher than during enteral administration. The elevated phytosterol levels have been associated with the development of liver dysfunction and the rare development of liver failure. There is limited information available in the literature related to phytosterol concentrations in lipid emulsions. The objective of the current study was to validate an assay for steroidal compounds found in lipid emulsions and to compare their concentrations in the most commonly used parenteral nutrition lipid emulsions: Liposyn® II, Liposyn® III, Lipofundin® MCT, Lipofundin® N, Structolipid®, Intralipid®, Ivelip® and ClinOleic®. Our data demonstrates that concentrations of the various steroidal compounds varied greatly between the eight lipid emulsions, with the olive oil-based lipid emulsion containing the lowest levels of phytosterols and cholesterol, and the highest concentration of squalene. The clinical impression of greater incidences of liver dysfunction with soybean versus MCT/LCT and olive/soy lipid emulsions may be reflective of the levels of phytosterols in these emulsions. This information may help guide future studies and clinical care of patients with lipid emulsion-associated liver dysfunction. PMID:23016123

  4. Pickering emulsions for skin decontamination.

    PubMed

    Salerno, Alicia; Bolzinger, Marie-Alexandrine; Rolland, Pauline; Chevalier, Yves; Josse, Denis; Briançon, Stéphanie

    2016-08-01

    This study aimed at developing innovative systems for skin decontamination. Pickering emulsions, i.e. solid-stabilized emulsions, containing silica (S-PE) or Fuller's earth (FE-PE) were formulated. Their efficiency for skin decontamination was evaluated, in vitro, 45min after an exposure to VX, one of the most highly toxic chemical warfare agents. Pickering emulsions were compared to FE (FE-W) and silica (S-W) aqueous suspensions. PE containing an oil with a similar hydrophobicity to VX should promote its extraction. All the formulations reduced significantly the amount of VX quantified on and into the skin compared to the control. Wiping the skin surface with a pad already allowed removing more than half of VX. FE-W was the less efficient (85% of VX removed). The other formulations (FE-PE, S-PE and S-W) resulted in more than 90% of the quantity of VX removed. The charge of particles was the most influential factor. The low pH of formulations containing silica favored electrostatic interactions of VX with particles explaining the better elimination from the skin surface. Formulations containing FE had basic pH, and weak interactions with VX did not improve the skin decontamination. However, these low interactions between VX and FE promote the transfer of VX into the oil droplets in the FE-PE.

  5. Pickering emulsions for skin decontamination.

    PubMed

    Salerno, Alicia; Bolzinger, Marie-Alexandrine; Rolland, Pauline; Chevalier, Yves; Josse, Denis; Briançon, Stéphanie

    2016-08-01

    This study aimed at developing innovative systems for skin decontamination. Pickering emulsions, i.e. solid-stabilized emulsions, containing silica (S-PE) or Fuller's earth (FE-PE) were formulated. Their efficiency for skin decontamination was evaluated, in vitro, 45min after an exposure to VX, one of the most highly toxic chemical warfare agents. Pickering emulsions were compared to FE (FE-W) and silica (S-W) aqueous suspensions. PE containing an oil with a similar hydrophobicity to VX should promote its extraction. All the formulations reduced significantly the amount of VX quantified on and into the skin compared to the control. Wiping the skin surface with a pad already allowed removing more than half of VX. FE-W was the less efficient (85% of VX removed). The other formulations (FE-PE, S-PE and S-W) resulted in more than 90% of the quantity of VX removed. The charge of particles was the most influential factor. The low pH of formulations containing silica favored electrostatic interactions of VX with particles explaining the better elimination from the skin surface. Formulations containing FE had basic pH, and weak interactions with VX did not improve the skin decontamination. However, these low interactions between VX and FE promote the transfer of VX into the oil droplets in the FE-PE. PMID:27021875

  6. Intravenous Lipid Emulsions in Parenteral Nutrition123

    PubMed Central

    Fell, Gillian L; Nandivada, Prathima; Gura, Kathleen M; Puder, Mark

    2015-01-01

    Fat is an important macronutrient in the human diet. For patients with intestinal failure who are unable to absorb nutrients via the enteral route, intravenous lipid emulsions play a critical role in providing an energy-dense source of calories and supplying the essential fatty acids that cannot be endogenously synthesized. Over the last 50 y, lipid emulsions have been an important component of parenteral nutrition (PN), and over the last 10–15 y many new lipid emulsions have been manufactured with the goal of improving safety and efficacy profiles and achieving physiologically optimal formulations. The purpose of this review is to provide a background on the components of lipid emulsions, their role in PN, and to discuss the lipid emulsions available for intravenous use. Finally, the role of parenteral fat emulsions in the pathogenesis and management of PN-associated liver disease in PN-dependent pediatric patients is reviewed. PMID:26374182

  7. Intravenous Lipid Emulsions in Parenteral Nutrition.

    PubMed

    Fell, Gillian L; Nandivada, Prathima; Gura, Kathleen M; Puder, Mark

    2015-09-01

    Fat is an important macronutrient in the human diet. For patients with intestinal failure who are unable to absorb nutrients via the enteral route, intravenous lipid emulsions play a critical role in providing an energy-dense source of calories and supplying the essential fatty acids that cannot be endogenously synthesized. Over the last 50 y, lipid emulsions have been an important component of parenteral nutrition (PN), and over the last 10-15 y many new lipid emulsions have been manufactured with the goal of improving safety and efficacy profiles and achieving physiologically optimal formulations. The purpose of this review is to provide a background on the components of lipid emulsions, their role in PN, and to discuss the lipid emulsions available for intravenous use. Finally, the role of parenteral fat emulsions in the pathogenesis and management of PN-associated liver disease in PN-dependent pediatric patients is reviewed. PMID:26374182

  8. 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. PMID:17877401

  9. Impact of acoustic cavitation on food emulsions.

    PubMed

    Krasulya, Olga; Bogush, Vladimir; Trishina, Victoria; Potoroko, Irina; Khmelev, Sergey; Sivashanmugam, Palani; Anandan, Sambandam

    2016-05-01

    The work explores the experimental and theoretical aspects of emulsification capability of ultrasound to deliver stable emulsions of sunflower oil in water and meat sausages. In order to determine optimal parameters for direct ultrasonic emulsification of food emulsions, a model was developed based on the stability of emulsion droplets in acoustic cavitation field. The study is further extended to investigate the ultrasound induced changes to the inherent properties of raw materials under the experimental conditions of sono-emulsification.

  10. Impact of acoustic cavitation on food emulsions.

    PubMed

    Krasulya, Olga; Bogush, Vladimir; Trishina, Victoria; Potoroko, Irina; Khmelev, Sergey; Sivashanmugam, Palani; Anandan, Sambandam

    2016-05-01

    The work explores the experimental and theoretical aspects of emulsification capability of ultrasound to deliver stable emulsions of sunflower oil in water and meat sausages. In order to determine optimal parameters for direct ultrasonic emulsification of food emulsions, a model was developed based on the stability of emulsion droplets in acoustic cavitation field. The study is further extended to investigate the ultrasound induced changes to the inherent properties of raw materials under the experimental conditions of sono-emulsification. PMID:26603612

  11. Nano-Emulsions:. Overview and Applications

    NASA Astrophysics Data System (ADS)

    Li, Xiang; Anton, Nicolas; Vandamme, Thierry

    2013-09-01

    Nano-emulsions, also called sub-micrometer emulsions, are one of the most important nanocarriers in nanomedicine. More than 40% active susbtances are hydrophobic and therefore they are difficult to be formulated using conventional approaches. Nano-emulsion systems are considered as new vehicles for hydrophobic drug administration because they can enhance the penetration and absorption of these hydrophobic active compounds and provide safer and more patient-compliant dosage forms. This chapter describes the conception and methods of preparation of nano-emulsions, their characterization methods and their applications in pharmacetical areas.

  12. Controlled generation of double emulsions in air.

    PubMed

    Liu, Dingsheng; Hakimi, Bejan; Volny, Michael; Rolfs, Joelle; Chen, Xudong; Turecek, Frantisek; Chiu, Daniel T

    2013-07-01

    This Letter describes the controlled generation of double emulsions in the gas phase, which was carried out using an integrated emitter in a poly(dimethylsiloxane) (PDMS) microfluidic chip. The integrated emitter was formed using a molding approach, in which metal wires with desirable diameters were used as emitter molds. The generation of double emulsions in air was achieved with electrohydrodynamics actuation, which offers controllable force exerting on the double emulsions. We developed this capability for future integration of droplet microfluidics with mass spectrometry (MS), where each aqueous droplet in the microchannel is introduced into the gas phase as a double emulsion for subsequent ionization and MS analysis. PMID:23767768

  13. Drop size stability assessment of fluorocarbon emulsions.

    PubMed

    Krafft, M P; Postel, M; Riess, J G; Ni, Y; Pelura, T J; Hanna, G K; Song, D

    1992-01-01

    The aging of fluorocarbon emulsions prepared with natural egg yolk phospholipids (EYP) has been studied and a linear variation (r2 greater than 0.95) of the mean average volume of the droplets with time has been observed. The slope of the experimental lines, called "Stability Parameter, S" can thus be taken as a representation of the rate of aging of the emulsions. Examples are given of use of parameter S to assess the effect of formulation and processing parameters on the stability of diverse fluorocarbon emulsions. S is a useful tool to compare emulsions and ascertain any factors of stabilization/destabilization. PMID:1391525

  14. Altering Emulsion Stability with Heterogeneous Surface Wettability.

    PubMed

    Meng, Qiang; Zhang, Yali; Li, Jiang; Lammertink, Rob G H; Chen, Haosheng; Tsai, Peichun Amy

    2016-01-01

    Emulsions-liquid droplets dispersed in another immiscible liquid-are widely used in a broad spectrum of applications, including food, personal care, agrochemical, and pharmaceutical products. Emulsions are also commonly present in natural crude oil, hampering the production and quality of petroleum fuels. The stability of emulsions plays a crucial role in their applications, but controlling the stability without external driving forces has been proven to be difficult. Here we show how heterogeneous surface wettability can alter the stability and dynamics of oil-in-water emulsions, generated by a co-flow microfluidic device. We designed a useful methodology that can modify a micro-capillary of desired heterogeneous wettability (e.g., alternating hydrophilic and hydrophobic regions) without changing the hydraulic diameter. We subsequently investigated the effects of flow rates and heterogeneous wettability on the emulsion morphology and motion. The experimental data revealed a universal critical timescale of advective emulsions, above which the microfluidic emulsions remain stable and intact, whereas below they become adhesive or inverse. A simple theoretical model based on a force balance can be used to explain this critical transition of emulsion dynamics, depending on the droplet size and the Capillary number-the ratio of viscous to surface effects. These results give insight into how to control the stability and dynamics of emulsions in microfluidics with flow velocity and different wettability. PMID:27256703

  15. Recent Studies of Pickering Emulsions: Particles Make the Difference.

    PubMed

    Wu, Jie; Ma, Guang-Hui

    2016-09-01

    In recent years, emulsions stabilized by micro- or nanoparticles (known as Pickering emulsions) have attracted much attention. Micro- or nanoparticles, as the main components of the emulsion, play a key role in the preparation and application of Pickering emulsions. The existence of particles at the interface between the oil and aqueous phases affects not only the preparation, but also the properties of Pickering emulsions, affording superior stability, low toxicity, and stimuli-responsiveness compared to classical emulsions stabilized by surfactants. These advantages of Pickering emulsions make them attractive, especially in biomedicine. In this review, the effects of the characteristics of micro- and nanoparticles on the preparation and properties of Pickering emulsions are introduced. In particular, the preparation methods of Pickering emulsions, especially uniform-sized emulsions, are listed. Uniform Pickering emulsions are convenient for both mechanistic research and applications. Furthermore, some biomedical applications of Pickering emulsions are discussed and the problems hindering their clinical application are identified.

  16. 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; Lu, Xinyi; Chen, Jihua; Kang, Nam-goo; Zhang, Qiuyu; Mays, Jimmy

    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 × 105 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

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

    SciTech Connect

    Wang, Wenwen; Wang, Weiyu; Li, Hui; Lu, Xinyi; Chen, Jihua; Kang, Nam-goo; Zhang, Qiuyu; Mays, Jimmy

    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, thermal 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 × 105 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.

  18. pH-Sensitive brush polymer-drug conjugates by ring-opening metathesis copolymerization.

    PubMed

    Zou, Jiong; Jafr, Goran; Themistou, Efrosyni; Yap, Yoonsing; Wintrob, Zachary A P; Alexandridis, Paschalis; Ceacareanu, Alice C; Cheng, Chong

    2011-04-21

    Representing a new category of polymer-drug conjugates, brush polymer-drug conjugates were prepared by ring-opening metathesis copolymerization. Following judicious structural design, these conjugates exhibited well-shielded drug moieties, significant water solubility, well-defined nanostructures, and acid-triggered drug release.

  19. Polymerization in emulsion microdroplet reactors

    NASA Astrophysics Data System (ADS)

    Carroll, Nick J.

    The goal of this research project is to utilize emulsion droplets as chemical reactors for execution of complex polymerization chemistries to develop unique and functional particle materials. Emulsions are dispersions of immiscible fluids where one fluid usually exists in the form of drops. Not surprisingly, if a liquid-to-solid chemical reaction proceeds to completion within these drops, the resultant solid particles will possess the shape and relative size distribution of the drops. The two immiscible liquid phases required for emulsion polymerization provide unique and complex chemical and physical environments suitable for the engineering of novel materials. The development of novel non-ionic fluorosurfactants allows fluorocarbon oils to be used as the continuous phase in a water-free emulsion. Such emulsions enable the encapsulation of almost any hydrocarbon compound in droplets that may be used as separate compartments for water-sensitive syntheses. Here, we exemplify the promise of this approach by suspension polymerization of polyurethanes (PU), in which the liquid precursor is emulsified into droplets that are then converted 1:1 into polymer particles. The stability of the droplets against coalescence upon removal of the continuous phase by evaporation confirms the formation of solid PU particles. These results prove that the water-free environment of fluorocarbon based emulsions enables high conversion. We produce monodisperse, cross-linked, and fluorescently labeled PU-latexes with controllable mesh size through microfluidic emulsification in a simple one-step process. A novel method for the fabrication of monodisperse mesoporous silica particles is presented. It is based on the formation of well-defined equally sized emulsion droplets using a microfluidic approach. The droplets contain the silica precursor/surfactant solution and are suspended in hexadecane as the continuous oil phase. The solvent is then expelled from the droplets, leading to

  20. Metallic nanoshells on porphyrin-stabilized emulsions

    DOEpatents

    Wang, Haorong; Song, Yujiang; Shelnutt, John A; Medforth, Craig J

    2013-10-29

    Metal nanostructures formed by photocatalytic interfacial synthesis using a porphyrin-stabilized emulsion template and the method for making the nanostructures. Catalyst-seeded emulsion droplets are employed as templates for hollow-nanoshell growth. The hollow metal nanospheres may be formed with or without inclusions of other materials.

  1. Altering Emulsion Stability with Heterogeneous Surface Wettability

    PubMed Central

    Meng, Qiang; Zhang, Yali; Li, Jiang; Lammertink, Rob G. H.; Chen, Haosheng; Tsai, Peichun Amy

    2016-01-01

    Emulsions–liquid droplets dispersed in another immiscible liquid–are widely used in a broad spectrum of applications, including food, personal care, agrochemical, and pharmaceutical products. Emulsions are also commonly present in natural crude oil, hampering the production and quality of petroleum fuels. The stability of emulsions plays a crucial role in their applications, but controlling the stability without external driving forces has been proven to be difficult. Here we show how heterogeneous surface wettability can alter the stability and dynamics of oil-in-water emulsions, generated by a co-flow microfluidic device. We designed a useful methodology that can modify a micro-capillary of desired heterogeneous wettability (e.g., alternating hydrophilic and hydrophobic regions) without changing the hydraulic diameter. We subsequently investigated the effects of flow rates and heterogeneous wettability on the emulsion morphology and motion. The experimental data revealed a universal critical timescale of advective emulsions, above which the microfluidic emulsions remain stable and intact, whereas below they become adhesive or inverse. A simple theoretical model based on a force balance can be used to explain this critical transition of emulsion dynamics, depending on the droplet size and the Capillary number–the ratio of viscous to surface effects. These results give insight into how to control the stability and dynamics of emulsions in microfluidics with flow velocity and different wettability. PMID:27256703

  2. Emulsions Droplet Capture Mechanism in Porous Media

    NASA Astrophysics Data System (ADS)

    Zeidani, Khalil; Polikar, Marcel

    2006-03-01

    This study was undertaken to investigate the physics of emulsion flow in porous media. The objective of experiments were to study the applicability of oil-in-water emulsion as a plugging agent in the vicinity of the well bore for thousands of Canadian gas wells that are continuously leaking gas to surface. The motion of oil droplets and the capture mechanisms were investigated through visualized experiments. Well-characterized emulsions were injected into a micro model resembling a two parallel plate model packed with glass beads. Effects of emulsion properties and wettability of the medium were studied on a plugging mechanism. The results demonstrate the reduction in permeability mainly due to droplets size exclusion compared to the pore constrictions. Also, smaller droplets may lodge and coalesce in pores crevices thereby accelerating the blockage process. Moreover, more viscous emulsions are more effective compared with the less viscous ones due to combined effects of capillary and viscous forces. The deposition of droplets was adjusted through utilizing different preflush solutions. Criteria were set for enhancing emulsion penetration depth thereby defining the extent of the blocked region. In conclusion, this work characterizes the physics of emulsion flow in porous media and demonstrates its application as a novel sealant in near well bore region. The novelty, which constitutes a step-change in technology, is a method that emplaces an emulsion at a desired location in underground media.

  3. Flows of Wet Foamsand Concentrated Emulsions

    NASA Technical Reports Server (NTRS)

    Nemer, Martin B.

    2005-01-01

    The aim of this project was is to advance a microstructural understanding of foam and emulsion flows. The dynamics of individual surfactant-covered drops and well as the collective behavior of dilute and concentrated was explored using numerical simulations. The long-range goal of this work is the formulation of reliable microphysically-based statistical models of emulsion flows.

  4. Altering Emulsion Stability with Heterogeneous Surface Wettability

    NASA Astrophysics Data System (ADS)

    Meng, Qiang; Zhang, Yali; Li, Jiang; Lammertink, Rob G. H.; Chen, Haosheng; Tsai, Peichun Amy

    2016-06-01

    Emulsions–liquid droplets dispersed in another immiscible liquid–are widely used in a broad spectrum of applications, including food, personal care, agrochemical, and pharmaceutical products. Emulsions are also commonly present in natural crude oil, hampering the production and quality of petroleum fuels. The stability of emulsions plays a crucial role in their applications, but controlling the stability without external driving forces has been proven to be difficult. Here we show how heterogeneous surface wettability can alter the stability and dynamics of oil-in-water emulsions, generated by a co-flow microfluidic device. We designed a useful methodology that can modify a micro-capillary of desired heterogeneous wettability (e.g., alternating hydrophilic and hydrophobic regions) without changing the hydraulic diameter. We subsequently investigated the effects of flow rates and heterogeneous wettability on the emulsion morphology and motion. The experimental data revealed a universal critical timescale of advective emulsions, above which the microfluidic emulsions remain stable and intact, whereas below they become adhesive or inverse. A simple theoretical model based on a force balance can be used to explain this critical transition of emulsion dynamics, depending on the droplet size and the Capillary number–the ratio of viscous to surface effects. These results give insight into how to control the stability and dynamics of emulsions in microfluidics with flow velocity and different wettability.

  5. Non-aqueous Isorefractive Pickering Emulsions

    PubMed Central

    2015-01-01

    Non-aqueous Pickering emulsions of 16–240 μm diameter have been prepared using diblock copolymer worms with ethylene glycol as the droplet phase and an n-alkane as the continuous phase. Initial studies using n-dodecane resulted in stable emulsions that were significantly less turbid than conventional water-in-oil emulsions. This is attributed to the rather similar refractive indices of the latter two phases. By utilizing n-tetradecane as an alternative oil that almost precisely matches the refractive index of ethylene glycol, almost isorefractive ethylene glycol-in-n-tetradecane Pickering emulsions can be prepared. The droplet diameter and transparency of such emulsions can be systematically varied by adjusting the worm copolymer concentration. PMID:25844544

  6. Non-aqueous Isorefractive Pickering Emulsions.

    PubMed

    Thompson, Kate L; Lane, Jacob A; Derry, Matthew J; Armes, Steven P

    2015-04-21

    Non-aqueous Pickering emulsions of 16-240 μm diameter have been prepared using diblock copolymer worms with ethylene glycol as the droplet phase and an n-alkane as the continuous phase. Initial studies using n-dodecane resulted in stable emulsions that were significantly less turbid than conventional water-in-oil emulsions. This is attributed to the rather similar refractive indices of the latter two phases. By utilizing n-tetradecane as an alternative oil that almost precisely matches the refractive index of ethylene glycol, almost isorefractive ethylene glycol-in-n-tetradecane Pickering emulsions can be prepared. The droplet diameter and transparency of such emulsions can be systematically varied by adjusting the worm copolymer concentration. PMID:25844544

  7. Non-aqueous Isorefractive Pickering Emulsions.

    PubMed

    Thompson, Kate L; Lane, Jacob A; Derry, Matthew J; Armes, Steven P

    2015-04-21

    Non-aqueous Pickering emulsions of 16-240 μm diameter have been prepared using diblock copolymer worms with ethylene glycol as the droplet phase and an n-alkane as the continuous phase. Initial studies using n-dodecane resulted in stable emulsions that were significantly less turbid than conventional water-in-oil emulsions. This is attributed to the rather similar refractive indices of the latter two phases. By utilizing n-tetradecane as an alternative oil that almost precisely matches the refractive index of ethylene glycol, almost isorefractive ethylene glycol-in-n-tetradecane Pickering emulsions can be prepared. The droplet diameter and transparency of such emulsions can be systematically varied by adjusting the worm copolymer concentration.

  8. Aging mechanism in model Pickering emulsion

    NASA Astrophysics Data System (ADS)

    Fouilloux, Sarah; Malloggi, Florent; Daillant, Jean; Thill, Antoine

    We study the stability of a model Pickering emulsion system. A special counter-flow microfluidics set-up was used to prepare monodisperse Pickering emulsions, with oil droplets in water. The wettability of the monodisperse silica nanoparticles (NPs) could be tuned by surface grafting and the surface coverage of the droplets was controlled using the microfluidics setup. A surface coverage as low as 23$\\%$ is enough to stabilize the emulsions and we evidence a new regime of Pickering emulsion stability where the surface coverage of emulsion droplets of constant size increases in time, in coexistence with a large amount of dispersed phase. Our results demonstrate that the previously observed limited coalescence regime where surface coverage tends to control the average size of the final droplets must be put in a broader perspective.

  9. Arresting relaxation in Pickering Emulsions

    NASA Astrophysics Data System (ADS)

    Atherton, Tim; Burke, Chris

    2015-03-01

    Pickering emulsions consist of droplets of one fluid dispersed in a host fluid and stabilized by colloidal particles absorbed at the fluid-fluid interface. Everyday materials such as crude oil and food products like salad dressing are examples of these materials. Particles can stabilize non spherical droplet shapes in these emulsions through the following sequence: first, an isolated droplet is deformed, e.g. by an electric field, increasing the surface area above the equilibrium value; additional particles are then adsorbed to the interface reducing the surface tension. The droplet is then allowed to relax toward a sphere. If more particles were adsorbed than can be accommodated by the surface area of the spherical ground state, relaxation of the droplet is arrested at some non-spherical shape. Because the energetic cost of removing adsorbed colloids exceeds the interfacial driving force, these configurations can remain stable over long timescales. In this presentation, we present a computational study of the ordering present in anisotropic droplets produced through the mechanism of arrested relaxation and discuss the interplay between the geometry of the droplet, the dynamical process that produced it, and the structure of the defects observed.

  10. [On bitumen emulsions in water].

    PubMed

    Rivas, Hercilio; Gutierrez, Xiomara; Silva, Felix; Chirinos, Manuel

    2003-01-01

    The most important factors, controlling the process of emulsification of highly viscous hydrocarbons in water, which are responsible for keeping the stability and other properties of these systems, are discused in this article. The effect of non-ionic surfactants, such as nonil phenol ethoxilated compounds on the interfacial behavior of bitumen/water systems is analyzed. The effect of the natural surfactants in presence or in absence of electrolytes is also analyzed. The procedures followed in order to obtain the optimal conditions of formulation and formation of bitumen in water emulsions, are discussed and the effect of some parameters on the mean droplet diameter and distribution are also considered. It was found that keeping constant mixing speed and time of mixing, the mean droplet diameter decreases as the bitumen concentration increases. Emulsion stability, which can be monitored by following the changes in mean droplet diameters and viscosity as a function of the storage time, is deeply affected by the type and concentration of surfactant. PMID:15916176

  11. Squalene and squalane emulsions as adjuvants.

    PubMed

    Allison, A C

    1999-09-01

    Microfluidized squalene or squalane emulsions are efficient adjuvants, eliciting both humoral and cellular immune responses. Microfluidization stabilizes the emulsions and allows sterilization by terminal filtration. The emulsions are stable for years at ambient temperature and can be frozen. Antigens are added after emulsification so that conformational epitopes are not lost by denaturation and to facilitate manufacture. A Pluronic block copolymer can be added to the squalane or squalene emulsion. Soluble antigens administered in such emulsions generate cytotoxic T lymphocytes able to lyse target cells expressing the antigen in a genetically restricted fashion. Optionally a relatively nontoxic analog of muramyl dipeptide (MDP) or another immunomodulator can be added; however, the dose of MDP must be restricted to avoid systemic side effects in humans. Squalene or squalane emulsions without copolymers or MDP have very little toxicity and elicit potent antibody responses to several antigens in nonhuman primates. They could be used to improve a wide range of vaccines. Squalene or squalane emulsions have been administered in human cancer vaccines, with mild side effects and evidence of efficacy, in terms of both immune responses and antitumor activity.

  12. Latest Developments in Nuclear Emulsion Technology

    NASA Astrophysics Data System (ADS)

    Morishima, Kunihiro

    Nuclear emulsion is high sensitive photographic film used for detection of three-dimensional trajectory of charged particles. These trajectories are recorded as tracks consist of a lot of silver grains. The size of silver grain is about 1 μm, so that nuclear emulsion has submicron three-dimensional spatial resolution, which gives us a few mrad three-dimensional angular resolution. The important technical progress was speed-up of the read-out technique of nuclear emulsions built with optical microscope system. We succeeded in developing a high-speed three-dimensional read-out system named Super Ultra Track Selector (S-UTS) with the operating read-out speed of approximately 50 cm2/h. Nowadays we are developing the nuclear emulsion gel independently in Nagoya University by introducing emulsion gel production machine. Moreover, we are developing nuclear emulsion production technologies (gel production, poring and mass production). In this paper, development of nuclear emulsion technologies for the OPERA experiment, applications by the technologies and current development are described.

  13. [Liberation of active agents from coherent emulsions].

    PubMed

    Erós, I; Csóka, I; Csányi, E; Aref, T

    2000-01-01

    Drug release from coherent emulsions containing high water concentration (50-80 w/w%) was studied. Composition of coherent systems was as follows: self-emulsifying wax and preserved water. Griseofulvin was applied as active agent in suspended form. The liberation experiments were carried out with Hanson vertical diffusion cell, acceptor phase was distilled water, membrane was celophane one. It was established that the time course of liberation of griseofulvin from coherent emulsions can be characterized with a multiplicative function and the exponent of this function is about 0.5. The quantity of released drug increased linearly with the water content and it decreased exponentially with the viscosity of coherent emulsions.

  14. Hydrodynamic model for drying emulsions.

    PubMed

    Feng, Huanhuan; Sprakel, Joris; van der Gucht, Jasper

    2015-08-01

    We present a hydrodynamic model for film formation in a dense oil-in-water emulsion under a unidirectional drying stress. Water flow through the plateau borders towards the drying end leads to the buildup of a pressure gradient. When the local pressure exceeds the critical disjoining pressure, the water films between droplets break and the droplets coalesce. We show that, depending on the critical pressure and the evaporation rate, the coalescence can occur in two distinct modes. At low critical pressures and low evaporation rates, coalescence occurs throughout the sample, whereas at high critical pressures and high evaporation rate, coalescence occurs only at the front. In the latter case, an oil layer develops on top of the film, which acts as a diffusive barrier and slows down film formation. Our findings, which are summarized in a state diagram for film formation, are in agreement with recent experimental findings.

  15. Theoretical consideration of bulk free-radical copolymerization with allowance for the preferential sorption of monomers into globular nanoreactors

    NASA Astrophysics Data System (ADS)

    Kuchanov, S. I.; Pogodin, S. G.

    2008-06-01

    The thermodynamics of a globular solution of binary copolymer in two-component solvent is theoretically considered. Classification of phase diagrams of such a solution is performed by their topological appearance. Based on the thermodynamic theory, binary bulk free-radical copolymerization under low conversions is examined in systems where macroradicals being in globular conformational state represent isolated nanoreactors. The theoretical results achieved permit an explanation of all qualitative peculiarities observed experimentally under copolymerization in such anomalous systems.

  16. Zwitterionic monomer graft copolymerization onto polyurethane surface through a PEG spacer

    NASA Astrophysics Data System (ADS)

    Huang, Jingjing; Xu, Weilin

    2010-04-01

    A new zwitterionic surface was obtained by a novel three-step grafting procedure. The zwitterionic monomer was introduced by cerium-induced graft copolymerization in the presence of N,N'-methylene bisacrylamide (MBAA) as cross-linking agent. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) analysis confirmed the MBAA could stimulate zwitterionic monomer grafting onto the membrane surface. Surface properties were also determined by atomic force microscope (AFM) and water contact angle. The hemocompatibility of the modified PU membranes was evaluated by the activated partial thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT). The TT and APTT of PU were significantly prolonged by the zwitterion of sulfobetaine monomer grafting copolymerization. The new polyurethane membrane could have a great potential in biomedical applications.

  17. Antimicrobial cotton containing N-halamine and quaternary ammonium groups by grafting copolymerization

    NASA Astrophysics Data System (ADS)

    Liu, Ying; Liu, Yin; Ren, Xuehong; Huang, T. S.

    2014-03-01

    The monomer (3-acrylamidopropyl)trimethylammonium chloride (APTMAC) was used to treat cotton fibers by grafting copolymerization. The grafted cotton fabrics were characterized by SEM image and FTIR spectra. The treated samples with quaternary ammonium groups could decrease 96.08% of Staphylococcus aureus and 48.74% of Escherichia coli O157:H7 within 30 min. After chlorination with dilute sodium hypochlorite, the treated cotton fabrics containing both N-halamine and quaternary ammonium groups effectively inactivated 100% (log reduction 5.82) of S. aureus and 100% (log reduction 6.26) of E. coli O157:H7 within 5 min of contact time. The grafting process of cotton fabric has small effect on the thermal stability and tensile strength, which favors the practical application. Compared to the traditional pad-dry-cure method to produce antibacterial materials, the radical grafting copolymerization method occurred in water without any organic solvents involved in the whole treatment.

  18. Fabrication of microarray of gel-immobilized compounds on a chip by copolymerization.

    SciTech Connect

    Vasiliskov, A. V.; Timofeev, E. N.; Surzhikov, S. A.; Drobyshev, A. L.; Shick, V. V.; Mirzabekov, A. D.; Biochip Technology Center; Engelhardt Inst. of Molecular Biology; Moscow Inst. of Physics and Technology

    1999-09-01

    The manufacturing of microchips containing oligonucleotides and proteins immobilized within gel pads, ranging in size from 10 x 10 to 100 x 100 {mu}m, is described. The microchips are produced by photo- or persulfate-induced copolymerization of unsaturated derivatives of biomolecules with acrylamide-bisacrylamide mixture. Oligonucleotides containing 5'-allyl or 5'-butenediol units were synthesized using standard phosphoramidite chemistry. Acryloyl residues were attached to a protein by a twostep procedure. Photopolymerization was induced by illumination of the monomer solution containing initiator with UV light through the mask. The mask was applied directly over the monomer solution or projected through a microscope. Alternatively, copolymerization was carried out in drops of aqueous solution of monomers containing ammonium persulfate. Drops with different allyl-oligonucleotides were distributed on a glass slide, and the polymerization was induced by diffusion of N,N,N',N'-tetramethylethylenediamine (TEMED) from a hexane solution that covered the aqueous drops.

  19. Asymmetric Alternating Copolymerization of Meso-epoxides and Cyclic Anhydrides: Efficient Access to Enantiopure Polyesters.

    PubMed

    Li, Jie; Liu, Ye; Ren, Wei-Min; Lu, Xiao-Bing

    2016-09-14

    Synthesis of stereoregular polyesters with main-chain chirality was achieved for the first time by the asymmetric copolymerization of meso-epoxides and cyclic anhydrides using catalyst systems based on enantiopure bimetallic complexes. The combination of the biphenol-linked dinuclear aluminum complex with tert-butyl groups in the phenolate ortho-positions and a nucleophilic co-catalyst was found to be more efficient in catalyzing this asymmetric copolymerization, affording enantiomerically enriched polyesters (up to 91% ee) with completely alternating structure and narrow molecular weight distribution. It was discovered that the isotactic-enriched poly(cyclopentene phthalate) is a typical semicrystalline material with a melting endothermic peak at 221 °C. This study is expected to provide a promising route to prepare various stereoregular polyesters having a wide variety of physical properties and degradability. PMID:27562940

  20. Aluminum pigment encapsulated by in situ copolymerization of styrene and maleic acid

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Ye, Hongqi; Tang, Xinde

    2007-11-01

    To improve its anticorrosion property, aluminum pigment was encapsulated by in situ copolymerization of styrene (St) and maleic acid (MA). It was found that the conversion of monomers (C), the percentage of grafting (PG) and the grafting efficiency (GE) could attain 92%, 12%, 25%, respectively, when m(BPO)/ m(St + MA) = 10% and m(St + MA)/ m(Al) = 10%. The optimum condition for protection factor was studied according to an orthogonal testing. When m(St + MA)/ m(Al) was 20%, the encapsulated aluminum pigment simultaneously showed good anticorrosion property and luster. FTIR, SEM and particle size analysis indicated that aluminum pigment had been successfully encapsulated with styrene-maleic acid copolymer by in situ copolymerization, which remarkably improved its anticorrosion property and the chelate complex formed between SMA and Al(III) was possibly the actual corrosion inhibitor.

  1. Random and block copolymerization in metal oxide gel synthesis from metalorganic compounds

    NASA Technical Reports Server (NTRS)

    Mukherjee, S. P.

    1985-01-01

    The introduction and development of the block copolymerization concept in metal oxide gel synthesis will in the future generate a new class of glass/microcrystalline materials. By the year 2004, better scientific understanding of the chemical principles controlling the distribution of network formers or modifiers in silicate gels will permit the synthesis of architecturally well-defined block polymers with unique high-performance behavior.

  2. Nickel(0)-catalyzed cycloaddition copolymerization involving two diynes and carbon dioxide to poly(2-pyrone)

    SciTech Connect

    Tsuda, Tetsuo; Ooi, Osamu; Maruta, Ken-ichi )

    1993-08-01

    A copolymerizability order of five diynes, i.e., 3,11-tetradecadiyne (A), 2,6-octadiyne (B), 1,4-di(2-hexynyl)benzene (C), 1,3-di(2-hexynyl)benzene (D), and 1,7-cyclotridecadiyne (E), in the nickel(0)-catalyzed 1:1 cycloaddition copolymerization of the diyne with CO[sub 2] to the poly(2-pyrone) was determined by the nickel(0)-catalyzed copolymerization involving two diynes and CO[sub 2]. The copolymerizability order obtained by analyzing the copolymer composition using [sup 1]H NMR spectroscopy was A [gt] E [gt] B [gt] C [gt] D. This order was explained in terms of the steric hindrance exerted by the substituent on the terminal C[triple bond]C bond of the cooligomer or the copolymer to its cycloaddition along with mobility of its terminal C[triple bond]C bond moiety for the cycloaddition. An order of cycloaddition reactivity of the diyne, which is related to formation of the cooligomer, was determined by measuring the unreacted diyne in the copolymerization involving five diynes and CO[sub 2] using gas chromatography. The result was E [gt] B [gt] C [gt] D [gt] A. Thus high copolymerizability of diyne A is noteworthy.

  3. Emulsion formation at the Pore-Scale

    NASA Astrophysics Data System (ADS)

    Armstrong, R. T.; Van Den Bos, P.; Berg, S.

    2012-12-01

    The use of surfactant cocktails to produce ultra-low interfacial tension between water and oil is an enhanced oil recovery method. In phase behavior tests three distinct emulsion phases are observed: (1) oil-in-water emulsion; (2) microemulsion; and (3) water-in-oil emulsion. However, it is unknown how phase behavior manifests at the pore-scale in a porous media system. What is the time scale needed for microemulsion formation? Where in the pore-space do the microemulsions form? And in what order do the different emulsion phases arrange during oil bank formation? To answer these questions micromodel experiments were conducted. These experiments are used to build a conceptual model for phase behavior at the pore-scale.

  4. Multi-body coalescence in Pickering emulsions.

    PubMed

    Wu, Tong; Wang, Haitao; Jing, Benxin; Liu, Fang; Burns, Peter C; Na, Chongzheng

    2015-01-12

    Particle-stabilized Pickering emulsions have shown unusual behaviours such as the formation of non-spherical droplets and the sudden halt of coalescence between individual droplets. Here we report another unusual behaviour of Pickering emulsions-the simultaneous coalescence of multiple droplets in a single event. Using latex particles, silica particles and carbon nanotubes as model stabilizers, we show that multi-body coalescence can occur in both water-in-oil and oil-in-water emulsions. The number of droplets involved in the nth coalscence event equals four times the corresponding number of the tetrahedral sequence in close packing. Furthermore, coalescence is promoted by repulsive latex and silica particles but inhibited by attractive carbon nanotubes. The revelation of multi-body coalescence is expected to help better understand Pickering emulsions in natural systems and improve their designs in engineering applications.

  5. Surfactant-enhanced cellulose nanocrystal Pickering emulsions.

    PubMed

    Hu, Zhen; Ballinger, Sarah; Pelton, Robert; Cranston, Emily D

    2015-02-01

    The effect of surfactants on the properties of Pickering emulsions stabilized by cellulose nanocrystals (CNCs) was investigated. Electrophoretic mobility, interfacial tension, confocal microscopy and three-phase contact angle measurements were used to elucidate the interactions between anionic CNCs and cationic alkyl ammonium surfactants didecyldimethylammonium bromide (DMAB) and cetyltrimethylammonium bromide (CTAB). Both surfactants were found to adsorb onto CNCs with concentration-dependent morphology. At low concentrations, individual surfactant molecules adsorbed with alkyl tails pointing outward leading to hydrophobic CNCs. At higher concentrations, above the surfactant's apparent critical micelle concentration, surfactant aggregate morphologies on CNCs were inferred and the hydrophobicity of CNCs decreased. DMAB, which has two alkyl tails, rendered the CNCs more hydrophobic than CTAB which has only a single alkyl tail, at all surfactant concentrations. The change in CNC wettability from surfactant adsorption was directly linked to emulsion properties; adding surfactant increased the emulsion stability, decreased the droplet size, and controlled the internal phase of CNC Pickering emulsions. More specifically, a double transitional phase inversion, from oil-in-water to water-in-oil and back to oil-in-water, was observed for emulsions with CNCs and increasing amounts of DMAB (the more hydrophobic surfactant). With CNCs and CTAB, no phase inversion was induced. This work represents the first report of CNC Pickering emulsions with surfactants as well as the first CNC Pickering emulsions that can be phase inverted. The ability to surface modify CNCs in situ and tailor emulsions by adding surfactants may extend the potential of CNCs to new liquid formulations and extruded/spray-dried materials.

  6. Fluorocarbon emulsions--the stability issue.

    PubMed

    Postel, M; Riess, J G; Weers, J G

    1994-01-01

    Long-term room temperature stability of ready-to-use concentrated fluorocarbon emulsions is necessary in order to fully exploit the therapeutic potential of fluorocarbons. Consequently, considerable efforts have been directed at investigating the physical nature of such emulsions, the mechanisms which lead to their degradation and the means of counteracting these. The particles which constitute typical fluorocarbon/egg yolk phospholipid emulsions have been identified to be surfactant-coated fluorocarbon droplets and lipid vesicles. Better understanding has been gained on the formation, structure and evolution of these particles during processing and storage. This has led to optimized formulations and processing, better control of emulsion characteristics and significantly improved stability. Molecular diffusion (Ostwald ripening or transcondensation) has been shown to be the maun mechanism of degradation when particles are less than 1 micron in diameter, even for the highly concentrated (volume fraction of fluorocarbon up to 50%) second generation fluorocarbon emulsions. Significant emulsion stabilization has been accomplished by adding fluorochemicals which are both less volatile and less water soluble, and nevertheless have an organ dwell time acceptable for intravascular use. The rate of molecular diffusion can also be reduced by decreasing the fluorocarbon/water interfacial tension; this was effectively achieved with appropriate, well-defined fluorinated surfactants. A further, novel means of stabilizing fluorocarbon-in-water emulsions makes use of mixed fluorocarbon-hydrocarbon amphiphiles which act as molecular dowels to reinforce the adhesion between the fluorocarbon phase and the lipophilic zone of the surfactant film. Both long-term room temperature stability, and particle-size control over a large range of diameter, have been achieved by applying this principle. All in all it can be said that the challenge of producing injectable fluorocarbon emulsions

  7. Microgel-stabilized smart emulsions for biocatalysis.

    PubMed

    Wiese, Susanne; Spiess, Antje C; Richtering, Walter

    2013-01-01

    Emulsions stabilized by stimuli-responsive microgels were used to perform enzyme catalysis. Many substrates are poorly water-soluble, while enzymes naturally require aqueous environments, thus resulting in a two-phase aqueous-organic system. Smart microgels allow an enzyme-catalyzed reaction to be performed in an emulsion that can be broken under controlled conditions to separate the reaction product and to recycle the enzyme (E) and the microgel.

  8. Conditions for equilibrium solid-stabilized emulsions.

    PubMed

    Kraft, Daniela J; de Folter, Julius W J; Luigjes, Bob; Castillo, Sonja I R; Sacanna, Stefano; Philipse, Albert P; Kegel, Willem K

    2010-08-19

    Particular types of solid-stabilized emulsions can be thermodynamically stable as evidenced by their spontaneous formation and monodisperse droplet size, which only depends on system parameters. Here, we investigate the generality of these equilibrium solid-stabilized emulsions with respect to the basic constituents: aqueous phase with ions, oil, and stabilizing particles. From systematic variations of these constituents, we identify general conditions for the spontaneous formation of monodisperse solid-stabilized emulsions droplets. We conclude that emulsion stability is achieved by a combination of solid particles as well as amphiphilic ions adsorbed at the droplet surface, and low interfacial tensions of the bare oil-water interface of order 10 mN/m or below. Furthermore, preferential wetting of the colloidal particles by the oil phase is necessary for thermodynamic stability. We demonstrate the sufficiency of these basic requirements by extending the observed thermodynamic stability to emulsions of different compositions. Our findings point to a new class of colloid-stabilized meso-emulsions with a potentially high impact on industrial emulsification processes due to the associated large energy savings. PMID:20701369

  9. Pickering emulsions stabilized by charged nanoparticles.

    PubMed

    Ridel, Laure; Bolzinger, Marie-Alexandrine; Gilon-Delepine, Nicole; Dugas, Pierre-Yves; Chevalier, Yves

    2016-09-28

    The stabilization of o/w Pickering emulsions in cases of weak adsorption of solid particles at the surface of oil droplets is addressed. Though the adsorption is usually very strong and irreversible when partial wetting conditions are fulfilled, electrostatic repulsions between charged solid particles act against the adsorption. The regime of weak adsorption was reached using charged silica nanoparticles at high pH and low ionic strength. O/w Pickering emulsions of the diisopropyl adipate oil were stabilized by colloidal nanoparticles of Ludox® AS40 consisting of non-aggregated particles of bare silica (hydrophilic). The combination of stability assessment, droplet size and electrokinetic potential measurements at various pH values, adsorption isotherms and cryo-SEM observations of the adsorbed layers disclosed the specificities of the stabilization of Pickering emulsions by adsorption of solid nanoparticles against strong electrostatic repulsions. Not only the long-term stability of emulsions was poor under strong electrostatic repulsions at high pH, but emulsification failed since full dispersion of oil could not be achieved. Emulsion stability was ensured by decreasing electrostatic repulsions by lowering the pH from 9 to 3. Stable emulsions were stabilized by a monolayer of silica particles at 54% coverage of the oil droplet surface at low silica content and an adsorption regime as multilayers was reached at higher concentrations of silica although there was no aggregation of silica in the bulk aqueous phase.

  10. A method for the characterization of emulsions, thermogranulometry: application to water-in-crude oil emulsion.

    PubMed

    Clausse, D; Gomez, F; Dalmazzone, C; Noik, C

    2005-07-15

    Emulsions are used in a wide range of applications and industries. Their size distribution is an important parameter because it influences most of the emulsion properties of emulsions. Several techniques of characterization are used to determine the granulometric distribution of emulsions, but they are generally limited to dilute samples and are based on complex algorithms. We describe a method that allows characterization of the droplet size distribution of emulsions using thermal analysis (thermogranulometry). This method permits the use of very concentrated samples without any dilution or perturbation of the system. We first define our method by a thermodynamic and kinetic approach. We studied a real system, i.e., crude oil emulsions, which form very concentrated, viscous, and opaque emulsions with water. We present a correlation between the size of droplets and their freezing temperature, corresponding to our system. Then we compare the size distributions obtained by our method with those derived by direct microscopy observations. The results obtained show that thermogranulometry may be an interesting method of characterization of emulsions, even for concentrated systems. PMID:15925639

  11. 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....

  12. 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....

  13. The atomization of water-oil emulsions

    SciTech Connect

    Broniarz-Press, L.; Ochowiak, M.; Rozanski, J.; Woziwodzki, S.

    2009-09-15

    The paper presents the results of experimental studies on atomization of the emulsions flowing through twin-fluid atomizers obtained by the use of the digital microphotography method. The main elements of the test installation were: nozzle, reservoir, pump and measurement units of liquid flow. The photographs were taken by a digital camera with automatic flash at exposure time of 1/8000 s and subsequently analyzed using Image Pro-Plus. The oils used were mineral oils 20-90, 20-70, 20-50 and 20-30. The studies were performed at flow rates of liquid phase changed from 0.0014 to 0.011 (dm{sup 3}/s) and gas phase changed from 0.28 to 1.4 (dm{sup 3}/s), respectively. The analysis of photos shows that the droplets being formed during the liquid atomization have very different sizes. The smallest droplets have diameters of the order of 10 {mu}m. The experimental results showed that the changes in physical properties of a liquid phase lead to the significant changes in the spray characteristics. The analysis of the photos of water and emulsions atomization process showed that the droplet sizes are dependent on gas and liquid flow rates, construction of nozzle and properties of liquid. The differences between characteristics of atomization for water and emulsions have been observed. Analysis of photos on forming the droplets in air-water and air-emulsions systems showed that droplets are bigger in air-emulsion system (at the same value of gas to liquid mass ratio). The values of Sauter mean diameter (SMD) increased with increase of volume fraction of oil in emulsion. The droplet size increased with emulsion viscosity. (author)

  14. Emulsion Mapping in Pork Meat Emulsion Systems with Various Lipid Types and Brown Rice Fiber.

    PubMed

    Choi, Yun-Sang; Kim, Young-Boong; Kim, Hyun-Wook; Hwang, Ko-Eun; Song, Dong-Heon; Jeong, Tae-Jun; Park, Jinhee; Kim, Cheon-Jei

    2015-01-01

    This study was conducted to evaluate emulsion mapping between emulsion stability and cooking yields, apparent viscosity, and hardness of reduced-fat pork emulsion systems. The reduced-fat emulsion systems were supplemented with different lipid types and brown rice bran fiber (BRF) concentrations. Compared to the control with 30% back fat, lower emulsion stability and higher cooking yield of meat emulsion systems were observed in T1 (30% back fat+1% BRF), T2 (30% back fat+2% BRF), T3 (30% back fat+3% BRF), T4 (30% back fat+6% BRF), and T15 (10% back fat+10% canola oil+2% BRF). Lower emulsion stability and higher apparent viscosity were observed in T1, T2, T3, T4, and T8 (20% back fat+3% BRF) compared to the control. Lower emulsion stability and higher hardness was detected in all treatments compared with the control, except T5 (20% back fat), T10 (10% back fat+10% canola oil+2% BRF), T11 (10% back fat+10% olive oil+2% BRF), T12 (10% back fat+10% grape seed oil+2% BRF), and T13 (10% back fat+10% soybean oil+2% BRF). This approach has been found particularly useful for highlighting differences among the emulsified properties in emulsion meat products. Thus, the results obtained with emulsion mapping are useful in making emulsified meat products of desired quality characteristics, partially replacing pork back fat with a mix of 10% back fat, 10% canola oil and 2% BRF was most similar to the control with 30% pork back fat. PMID:26761836

  15. Emulsion Mapping in Pork Meat Emulsion Systems with Various Lipid Types and Brown Rice Fiber

    PubMed Central

    Choi, Yun-Sang; Kim, Young-Boong; Park, Jinhee

    2015-01-01

    This study was conducted to evaluate emulsion mapping between emulsion stability and cooking yields, apparent viscosity, and hardness of reduced-fat pork emulsion systems. The reduced-fat emulsion systems were supplemented with different lipid types and brown rice bran fiber (BRF) concentrations. Compared to the control with 30% back fat, lower emulsion stability and higher cooking yield of meat emulsion systems were observed in T1 (30% back fat+1% BRF), T2 (30% back fat+2% BRF), T3 (30% back fat+3% BRF), T4 (30% back fat+6% BRF), and T15 (10% back fat+10% canola oil+2% BRF). Lower emulsion stability and higher apparent viscosity were observed in T1, T2, T3, T4, and T8 (20% back fat+3% BRF) compared to the control. Lower emulsion stability and higher hardness was detected in all treatments compared with the control, except T5 (20% back fat), T10 (10% back fat+10% canola oil+2% BRF), T11 (10% back fat+10% olive oil+2% BRF), T12 (10% back fat+10% grape seed oil+2% BRF), and T13 (10% back fat+10% soybean oil+2% BRF). This approach has been found particularly useful for highlighting differences among the emulsified properties in emulsion meat products. Thus, the results obtained with emulsion mapping are useful in making emulsified meat products of desired quality characteristics, partially replacing pork back fat with a mix of 10% back fat, 10% canola oil and 2% BRF was most similar to the control with 30% pork back fat. PMID:26761836

  16. High pressure-resistant nonincendive emulsion explosive

    DOEpatents

    Ruhe, Thomas C.; Rao, Pilaka P.

    1994-01-01

    An improved emulsion explosive composition including hollow microspheres/bulking agents having high density and high strength. The hollow microspheres/bulking agents have true particle densities of about 0.2 grams per cubic centimeter or greater and include glass, siliceous, ceramic and synthetic resin microspheres, expanded minerals, and mixtures thereof. The preferred weight percentage of hollow microspheres/bulking agents in the composition ranges from 3.0 to 10.0 A chlorinated paraffin oil, also present in the improved emulsion explosive composition, imparts a higher film strength to the oil phase in the emulsion. The emulsion is rendered nonincendive by the production of sodium chloride in situ via the decomposition of sodium nitrate, a chlorinated paraffin oil, and sodium perchlorate. The air-gap sensitivity is improved by the in situ formation of monomethylamine perchlorate from dissolved monomethylamine nitrate and sodium perchlorate. The emulsion explosive composition can withstand static pressures to 139 bars and dynamic pressure loads on the order of 567 bars.

  17. Tuneable Rheological Properties of Fluorinated Pickering Emulsions

    NASA Astrophysics Data System (ADS)

    Chacon Orellana, Laura Andreina; Riechers, Birte; Caen, Ouriel; Baret, Jean-Christophe

    Pickering emulsions are an appealing approach to stabilize liquid-liquid dispersions without surfactants. Recently, amphiphilic silica nanoparticles have been proposed as an alternative to surfactants for droplet microfluidics applications, where aqueous drops are stabilized in fluorinated oils. This system, proved to be effective in preventing the leakage of resorufin, a model dye that was known to leak in surfactant-stabilized drops. The overall capabilities of droplet-based microfluidics technology is highly dependent on the dynamic properties of droplets, interfaces and emulsions. Therefore, fluorinated pickering emulsions dynamic properties need to be characterized, understood and controlled to be used as a substitute of already broadly studied emulsions for droplet microfluidics applications. In this study, fluorinated pickering emulsions have been found to behave as a Herschel Bulkley fluid, representing a challenge for common microfluidic operations as re-injection and sorting of droplets. We found that this behavior is controlled by the interaction between the interfacial properties of the particle-laden interface and the bulk properties of the two phases

  18. Synthesis of polymer latex particles decorated with organically-modified laponite clay platelets via emulsion polymerization.

    PubMed

    Herrera, Norma Negrete; Persoz, Stéphanie; Putaux, Jean-Luc; David, Laurent; Bourgeat-Lami, Elodie

    2006-02-01

    We report a new route to colloidal nanocomposites consisting of polymer latex particles covered with Laponite clay nanoplatelets. These composite particles are prepared by seeded emulsion (co)polymerization of styrene and butyl acrylate from Laponite clay suspensions previously functionalized by ion exchange using either a free radical initiator: 2,2-azobis (2-methylpropionamidine) hydrochloride (AIBA) or a cationic vinyl monomer: 2-(methacryloyloxy) ethyl trimethyl ammonium chloride (MADQUAT). The successful intercalation of the cationic reactive molecules was confirmed by elemental analysis, FTIR, 13C solid-state NMR and WAXD. The organically-modified clays were dispersed into water with the help of tetrasodium pyrophosphate and an anionic surfactant. stable latexes, produced under different experimental conditions, were successfully obtained from the clay suspensions. Cryo-TEM images of the resulting latexes showed spherical composite particles with diameters in the 50-250 nm range with clay sheets located on their surface. This paper reports on the effect of the processing conditions on the particle morphology and latex stability, and describes the mechanism of formation of the nanocomposite particles.

  19. Stimuli-responsive Pickering emulsions: recent advances and potential applications.

    PubMed

    Tang, Juntao; Quinlan, Patrick James; Tam, Kam Chiu

    2015-05-14

    Pickering emulsions possess many advantages over traditional surfactant stabilized emulsions. For example, Pickering emulsions impart better stability against coalescence and, in many cases, are biologically compatible and environmentally friendly. These characteristics open the door for their use in a variety of industries spanning petroleum, food, biomedicine, pharmaceuticals, and cosmetics. Depending on the application, rapid, but controlled stabilization and destabilization of an emulsion may be necessary. As a result, Pickering emulsions with stimuli-responsive properties have, in recent years, received a considerable amounts of attention. This paper provides a concise and comprehensive review of Pickering emulsion systems that possess the ability to respond to an array of external triggers, including pH, temperature, CO2 concentration, light intensity, ionic strength, and magnetic field. Potential applications for which stimuli-responsive Pickering emulsion systems would be of particular value, such as emulsion polymerization, enhanced oil recovery, catalyst recovery, and cosmetics, are discussed.

  20. Responsive emulsions stabilized by stimuli-sensitive microgels: emulsions with special non-Pickering properties.

    PubMed

    Richtering, Walter

    2012-12-18

    Recent studies revealing the unique properties of microgel-stabilized responsive emulsions are discussed, and microgels are compared to classical rigid-particle Pickering stabilizers. Microgels are strongly swollen, lyophilic particles that become deformed at the oil-water interface and protrude only a little into the oil phase. Temperature- and pH-sensitive microgels allow us to prepare temperature- and pH-sensitive emulsions and thus enable us to prepare and break emulsions on demand. Although such emulsions are sensitive to pH, the stabilization of droplets is not due to electrostatic repulsion, instead the viscoelastic properties of the interface seem to dominate droplet stability. Being soft and porous, microgels behave distinctly differently from rigid particles at the interface: they are deformed and strongly flattened especially in the case of oil-in-water emulsions. The microgels are located mainly on the water side of the interface for both oil-in-water and water-in-oil emulsions. In contrast to rigid, solid particles, the behavior of microgels at oil-water interfaces does not depend only on the interfacial tension but also on the balance among the interfacial tension, swelling, elasticity, and deformability of the microgel, which needs to be considered. It is obvious that microgels as soft, porous particles are significantly different from classical rigid colloidal stabilizers in Pickering emulsions and we suggest avoiding the term Pickering emulsion when swollen microgels are employed. Microgel-stabilized emulsions require the development of new theoretical models to understand their properties. They open the door to new sophisticated applications.

  1. Near-infrared luminescent copolymerized hybrid materials built from tin nanoclusters and PMMA.

    PubMed

    Fan, Weiqiang; Feng, Jing; Song, Shuyan; Lei, Yongqian; Zhou, Liang; Zheng, Guoli; Dang, Song; Wang, Song; Zhang, Hongjie

    2010-10-01

    Novel near-infrared (NIR) luminescent copolymerized hybrid materials were prepared by covalently grafting and physically doping Ln complexes (Ln = Er, Sm, Yb, and Nd) into a copolymer matrix built from nanobuilding blocks. The structures of the obtained hybrid materials were investigated by Fourier transform infrared (FTIR) spectra, nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and thermogravimetric analysis (TGA). In the photoluminescence studies, the hybrid materials showed characteristic NIR luminescence of corresponding Ln(3+) ions through intramolecular energy transfer from ligands to Ln(3+) ions. Transparent films of these materials can be easily prepared through spin-coating on indium tin oxide (ITO) glasses taking advantage of the matrix nature.

  2. Chemoselective Alternating Copolymerization of Limonene Dioxide and Carbon Dioxide: A New Highly Functional Aliphatic Epoxy Polycarbonate.

    PubMed

    Li, Chunliang; Sablong, Rafaël J; Koning, Cor E

    2016-09-12

    The alternating copolymerization of biorenewable limonene dioxide with carbon dioxide (CO2 ) catalyzed by a zinc β-diiminate complex is reported. The chemoselective reaction results in linear amorphous polycarbonates that carry pendent methyloxiranes and exhibit glass transition temperatures (Tg ) up to 135 °C. These polycarbonates can be efficiently modified by thiols or carboxylic acids in combination with lithium hydroxide or tetrabutylphosphonium bromide as catalysts, respectively, without destruction of the main chain. Moreover, polycarbonates bearing pendent cyclic carbonates can be quantitatively prepared by CO2 insertion catalyzed by lithium bromide.

  3. Chemoselective Alternating Copolymerization of Limonene Dioxide and Carbon Dioxide: A New Highly Functional Aliphatic Epoxy Polycarbonate.

    PubMed

    Li, Chunliang; Sablong, Rafaël J; Koning, Cor E

    2016-09-12

    The alternating copolymerization of biorenewable limonene dioxide with carbon dioxide (CO2 ) catalyzed by a zinc β-diiminate complex is reported. The chemoselective reaction results in linear amorphous polycarbonates that carry pendent methyloxiranes and exhibit glass transition temperatures (Tg ) up to 135 °C. These polycarbonates can be efficiently modified by thiols or carboxylic acids in combination with lithium hydroxide or tetrabutylphosphonium bromide as catalysts, respectively, without destruction of the main chain. Moreover, polycarbonates bearing pendent cyclic carbonates can be quantitatively prepared by CO2 insertion catalyzed by lithium bromide. PMID:27529815

  4. Graft copolymerization onto polybutadiene: Cross-linking and thermal degradation of vinyl polymers and copolymers

    NASA Astrophysics Data System (ADS)

    Jiang, Dayue (David)

    This work consists of three parts. In Part I, the graft copolymerization of methyl methacrylate, methyl acrylate, methacylic acid and acrylic acid onto polybutadiene and its copolymers by benzoyl peroxide, BPO, or 2, 2'azobis(2-methylpropionitrile), AIBN, initiation were explored. The results show that these monomers can be grafted onto butadiene region of butadiene-containing polymers. The extent of both graft copolymerization and homopolymerization are dependent on the time and temperature of the reaction and the concentration of all of the reactants. One must specify the monomer, initiator and solvent for the efficient graft copolymerization. The methyl methacrylate adds directly to the radical sites which are formed on the backbone by the interaction of the polymer and the primary radical form the initiator, while for the other three monomers, the graft copolymerization occurs by addition of macro-radical to the double bonds. In Part II, the cross-linking of polybutadiene, butadiene-styrene copolymers, and polystyrene by irradiation, thermal and chemical processes, and Friedel-Crafts chemistry and the effect of cross-linking on the thermal stability were investigated. The proof of cross-linking of the polymer comes from the insolubility of the product after the cross-linking reaction and is characterized by gel content and swelling ratio. The results show that the thermal stability of the polymer can be improved by cross-linking. In Part III, the thermal degradation of three vinyl polymers, poly(vinylsulfonic acid) and its sodium salt and poly(vinylphosphonic acid) were studied by combination technique: TGA/FTIR. The results show that TGA/FTIR combined with analysis of residues provides an excellent opportunity to understand the degradation pathway of the compounds. The observation of foaming indicates that the char which is formed contains carbon as well as the inorganic salts which have been observed. The carbon is in a partially graphitized form. The salts

  5. Relative rates for plasma homo- and copolymerizations of olefins in a homologous series of fluorinated ethylenes

    NASA Technical Reports Server (NTRS)

    Golub, M. A.; Wydeven, T.

    1997-01-01

    It is well known that the rate of plasma polymerization, or deposition rate, of a given monomer depends on various plasma process parameters, e.g., monomer flow rate, pressure, power, frequency (DC, rf or microwave), location of the substrate in the reactor, reactor geometry or configuration, and temperature. In contrast, little work has been done to relate deposition rates to monomer structures for a homologous series of monomers where the rates are obtained under identical plasma process parameters. For the particular series of fluorinated ethylenes (C2HxF4-x; x = 0-4), deposition rates were reported for ethylene (ET), vinyl fluoride, vinylidene fluoride and tetrafluoroethylene (TFE), but for plasma polymerizations carried out under different discharge conditions, e.g., pressure, current density, and electrode temperature. Apparently, relative deposition rates were reported for only two members of that series (ET, x = 4, and TFE, x = 0) for which the plasma polymerizations were conducted under identical conditions. We now present relative deposition rates for both homopolymerizations and copolymerizations of the entire series of fluorinated ethylenes (x = 0-4). Our interest in such rates stems from prior work on the plasma copolymerization of ET and TFE in which it was found that the deposition rates for the plasma copolymers, when plotted versus mol % TFE in the ET/TFE feed stock, followed a concave-downward curve situated above the straight line joining the deposition rates for the plasma homopolymers. This type of plot (observed also for an argon-ET/TFE plasma copolymerization) indicated a positive interaction between ET and TFE such that each monomer apparently "sensitized" the plasma copolymerization of the other. Since the shape of that plot is not altered if mol % TFE is replaced by F/C, the fluorine-to-carbon ratio, this paper aims (1) to show how the relative deposition rates for plasma copolymers drawn from all pairs of monomers in the C2HxF4-x series

  6. Forces acting in quasi 2d emulsions

    NASA Astrophysics Data System (ADS)

    Orellana, Carlos; Lowensohn, Janna; Weeks, Eric

    We study the forces in a quasi two dimensional emulsion system. Our samples are oil-in-water emulsions confined between two close-spaced parallel plates, so that the oil droplets are deformed into pancake shapes. By means of microscopy, we measure the droplet positions and their deformation, which we can relate to the contact forces due to surface tension. We improve over prior work in our lab, achieving a better force resolution. We use this result to measure and calibrate the viscous forces acting in our system, which fully determine all the forces on the droplets. Our results can be applied to study static configurations of emulsion, as well as faster flows.

  7. [Liberation of active agents from coherent emulsions].

    PubMed

    Erós, I; Csóka, I; Csányi, E; Aref, T

    2000-01-01

    Drug release from coherent emulsions containing high water concentration (50-80 w/w%) was studied. Composition of coherent systems was as follows: self-emulsifying wax and preserved water. Griseofulvin was applied as active agent in suspended form. The liberation experiments were carried out with Hanson vertical diffusion cell, acceptor phase was distilled water, membrane was celophane one. It was established that the time course of liberation of griseofulvin from coherent emulsions can be characterized with a multiplicative function and the exponent of this function is about 0.5. The quantity of released drug increased linearly with the water content and it decreased exponentially with the viscosity of coherent emulsions. PMID:11379037

  8. Multi-body coalescence in Pickering emulsions

    NASA Astrophysics Data System (ADS)

    Wu, Tong; Wang, Haitao; Jing, Benxin; Liu, Fang; Burns, Peter C.; Na, Chongzheng

    2015-01-01

    Particle-stabilized Pickering emulsions have shown unusual behaviours such as the formation of non-spherical droplets and the sudden halt of coalescence between individual droplets. Here we report another unusual behaviour of Pickering emulsions—the simultaneous coalescence of multiple droplets in a single event. Using latex particles, silica particles and carbon nanotubes as model stabilizers, we show that multi-body coalescence can occur in both water-in-oil and oil-in-water emulsions. The number of droplets involved in the nth coalscence event equals four times the corresponding number of the tetrahedral sequence in close packing. Furthermore, coalescence is promoted by repulsive latex and silica particles but inhibited by attractive carbon nanotubes. The revelation of multi-body coalescence is expected to help better understand Pickering emulsions in natural systems and improve their designs in engineering applications.

  9. Detection of low energy antimatter with emulsions

    NASA Astrophysics Data System (ADS)

    Aghion, S.; Ariga, A.; Ariga, T.; Bollani, M.; Dei Cas, E.; Ereditato, A.; Evans, C.; Ferragut, R.; Giammarchi, M.; Pistillo, C.; Romé, M.; Sala, S.; Scampoli, P.

    2016-06-01

    Emulsion detectors feature a very high position resolution and consequently represent an ideal device when particle detection is required at the micrometric scale. This is the case of quantum interferometry studies with antimatter, where micrometric fringes have to be measured. In this framework, we designed and realized a new emulsion based detector characterized by a gel enriched in terms of silver bromide crystal contents poured on a glass plate. We tested the sensitivity of such a detector to low energy positrons in the range 10–20 keV . The obtained results prove that nuclear emulsions are highly efficient at detecting positrons at these energies. This achievement paves the way to perform matter-wave interferometry with positrons using this technology.

  10. Optical diffusers based on silicone emulsions

    NASA Astrophysics Data System (ADS)

    Wang, Jui-Hao; Lien, Shui-Yang; Ho, Jeng-Rong; Shih, Teng-Kai; Chen, Chia-Fu; Chen, Chien-Chung; Whang, Wha-Tzong

    2009-12-01

    The present study provides an experimental approach for fabricating optical diffuser films based on silicone emulsions. The silicone emulsion consisting of silicone polymer (Sylgard 184) and NaCl aq. solution was used as the optical material of diffusers, wherein NaCl aq. solution was severed as surfactant to stabilize the emulsions. After stirring mechanically, microscaled water drop with various sizes distributed randomly in silicone polymer, wherein water drop was used as scattering diffusion particles. To modulate the volume of NaCl aq. solution, the diffusing performance of diffusers could be change by different amount drop particles. Thereafter, an optical examination was carried out to characterize optical properties, transmittance, and light diffusivity of volumetric diffuser films.

  11. Electrochemistry of a single attoliter emulsion droplet in collisions.

    PubMed

    Kim, Byung-Kwon; Kim, Jiyeon; Bard, Allen J

    2015-02-18

    We report here the electrochemistry of emulsion droplets by observing single emulsion droplet collisions with selective electrochemical reduction on an ultramicroelectrode (UME). With appropriately applied potentials at an UME, we can observe the electrochemical effects of single collision signals from the complete electrolysis of single emulsion droplets, or selective electrolysis of redox species in single emulsion droplets. This was observed with nitrobenzene (NB), 7,7,8,8-tetracyanoquinodimethane (TCNQ), and ionic liquid. The NB, TCNQ, and ionic liquid act as emulsion material, redox specie, and emulsifier (and electrolyte), respectively. NB emulsions and NB (TCNQ) emulsions were made by ultrasonic processing. During the amperometric current-time (i-t) curve measurement with NB/water emulsion at -0.65 V, reduction of NB emulsion droplets was measured. In the case of less negative potentials, e.g., at -0.45 V with a NB (TCNQ) emulsion, selective reduction of TCNQ in NB droplet was measured. Spike-like responses from electrolysis of NB or TCNQ in each experiment were observed. From these single-particle collision results of NB and NB (TCNQ) emulsions, the collision frequency, size distribution, i-t decay behavior of emulsion droplets, and possible mechanisms are discussed.

  12. Pickering emulsions and capsules stabilized by wool powder particles.

    PubMed

    Hikima, Takako; Nonomura, Yoshimune

    2011-01-01

    We prepared emulsions and capsules that were stabilized by wool powder particles. These powder particles were adsorbed on oil-water interfaces, and they formed both oil-in-water and water-in-oil emulsions. These emulsions were observed in ternary systems containing silicone oil, n-dodecane, fluoric oil, oleic acid, or linoleic acid as the oil phase.

  13. Development of Novel Polymeric Prodrugs Synthesized by Mechanochemical Solid-State Copolymerization of Hydroxyethylcellulose and Vinyl Monomers.

    PubMed

    Doi, Naoki; Sasai, Yasushi; Yamauchi, Yukinori; Adachi, Tetsuo; Kuzuya, Masayuki; Kondo, Shin-ichi

    2015-01-01

    Novel polymeric prodrugs were synthesized by mechanochemical solid-state copolymerization of hydroxyethylcellulose and the methacryloyloxy derivative of 5-fluorouracil (5-FU). Copolymerization was about 94% complete after 4 h, and the polymeric prodrug was quantitatively obtained after 14 h of reaction. The number average molecular weight (Mn) and polydispersity (H) of the polymeric prodrug were 39000 g/mol and 6.20, respectively. Mechanical fracturing of the polymer in a stainless steel twin-shell blender improved these properties (Mn=16000 g/mol and H=1.94). 5-FU was sustainably released from the polymeric prodrugs, and the rate was not affected by the molecular weight or molecular weight distribution of the prodrug under the experimental conditions used. These results suggest that novel polymeric prodrugs composed of a polysaccharide and a synthetic polymer can be fabricated by mechanochemical solid-state copolymerization under anaerobic conditions.

  14. Development of Novel Polymeric Prodrugs Synthesized by Mechanochemical Solid-State Copolymerization of Hydroxyethylcellulose and Vinyl Monomers.

    PubMed

    Doi, Naoki; Sasai, Yasushi; Yamauchi, Yukinori; Adachi, Tetsuo; Kuzuya, Masayuki; Kondo, Shin-ichi

    2015-01-01

    Novel polymeric prodrugs were synthesized by mechanochemical solid-state copolymerization of hydroxyethylcellulose and the methacryloyloxy derivative of 5-fluorouracil (5-FU). Copolymerization was about 94% complete after 4 h, and the polymeric prodrug was quantitatively obtained after 14 h of reaction. The number average molecular weight (Mn) and polydispersity (H) of the polymeric prodrug were 39000 g/mol and 6.20, respectively. Mechanical fracturing of the polymer in a stainless steel twin-shell blender improved these properties (Mn=16000 g/mol and H=1.94). 5-FU was sustainably released from the polymeric prodrugs, and the rate was not affected by the molecular weight or molecular weight distribution of the prodrug under the experimental conditions used. These results suggest that novel polymeric prodrugs composed of a polysaccharide and a synthetic polymer can be fabricated by mechanochemical solid-state copolymerization under anaerobic conditions. PMID:26423117

  15. Copper mediated controlled radical copolymerization of styrene and 2-ethylhexyl acrylate and determination of their reactivity ratios.

    NASA Astrophysics Data System (ADS)

    Koiry, Bishnu; Singha, Nikhil

    2014-10-01

    Copolymerization is an important synthetic tool to prepare polymers with desirable combination of properties which are difficult to achieve from the different homopolymers concerned. This investigation reports the copolymerization of 2-ethylhexyl acrylate (EHA) and styrene using copper bromide (CuBr) as catalyst in combination with N,N,N’,N”,N”- pentamethyldiethylenetriamine (PMDETA) as ligand and 1-phenylethyl bromide (PEBr) as initiator. Linear kinetic plot and linear increase in molecular weights versus conversion indicate that copolymerization reactions were controlled. The copolymer composition was calculated using 1H NMR studies. The reactivity ratio of styrene and EHA (r1 and r2) were determined using the Finemann-Ross (FR), inverted Finemann-Ross (FR) and Kelen-Tudos (KT) methods. Thermal properties of the copolymers were also studied by using TGA and DSC analysis.

  16. Copper mediated controlled radical copolymerization of styrene and 2-ethylhexyl acrylate and determination of their reactivity ratios.

    PubMed

    Koiry, Bishnu P; Singha, Nikhil K

    2014-01-01

    Copolymerization is an important synthetic tool to prepare polymers with desirable combination of properties which are difficult to achieve from the different homopolymers concerned. This investigation reports the copolymerization of 2-ethylhexyl acrylate (EHA) and styrene using copper bromide (CuBr) as catalyst in combination with N,N,N',N″,N″- pentamethyldiethylenetriamine (PMDETA) as ligand and 1-phenylethyl bromide (PEBr) as initiator. Linear kinetic plot and linear increase in molecular weights vs. conversion indicate that copolymerization reactions were controlled. The copolymer composition was calculated using (1)H NMR studies. The reactivity ratio of styrene and EHA (r1 and r2) were determined using the Finemann-Ross (FR), inverted Finemann-Ross (IFR), and Kelen-Tudos (KT) methods. Thermal properties of the copolymers were also studied by using TGA and DSC analysis. PMID:25368866

  17. Copolymerization of Epichlorohydrin and CO2 Using Zinc Glutarate: An Additional Application of ZnGA in Polycarbonate Synthesis.

    PubMed

    Sudakar, Padmanaban; Sivanesan, Dharmalingam; Yoon, Sungho

    2016-05-01

    The use of zinc glutarate (ZnGA) as a heterogeneous catalyst for the copolymerization of epichlorohydrin, an epoxide with an electron-withdrawing substituent, and CO2 is reported. This catalyst shows the highest selectivity (98%) for polycarbonate over the cyclic carbonate in epichlorohydrin/CO2 copolymerization under mild conditions. The (epichlorohydrin-co-CO2 ) polymer exhibits a high glass transition temperature (Tg ), 44 °C, which is the maximum Tg value obtained for the (epichlorohydrin-co-CO2 ) polymer to date.

  18. Extraction of palm tree cellulose and its functionalization via graft copolymerization.

    PubMed

    Al-Hoqbani, Abdulmajeed A; Abdel-Halim, E S; Al-Deyab, Salem S

    2014-09-01

    The work in this paper was planned with the aim of extracting the cellulosic component of palm tree waste and functionalizing this cellulose through graft copolymerization with acrylic acid. The cellulose extraction included hot alkali treatment with aqueous sodium hydroxide to remove the non-cellulosic binding materials. The alkali treatment was followed by an oxidative bleaching using peracid/hydrogen peroxide mixture with the aim of removing the rest of non-cellulosic materials to improve the fiber hydrophilicity and accessibility towards further grafting reaction. Optimum conditions for cellulose extraction are boiling in 5% (W/V) NaOH in a material to liquor ratio of 1:20 for 1 h then bleaching with 60 ml/l bleaching mixture at initial pH value of 6.5 for 30 min. The pH of the bleaching medium is turned to the alkaline range 11 and bleaching continues for extra 30 min. Graft copolymerization reaction was initiated by potassium bromate/thiourea dioxide redox system. Optimum conditions for grafting are 30 mmol of potassium bromate, 30 mmol of thiourea dioxide and 150 g of acrylic acid (each per 100 g of cellulose). The polymerization reaction was carried out for 120 min at 50°C using a material to liquor ratio of 1:20. PMID:25020080

  19. A general theory of kinetics and thermodynamics of steady-state copolymerization.

    PubMed

    Shu, Yao-Gen; Song, Yong-Shun; Ou-Yang, Zhong-Can; Li, Ming

    2015-06-17

    Kinetics of steady-state copolymerization has been investigated since the 1940s. Irreversible terminal and penultimate models were successfully applied to a number of comonomer systems, but failed for systems where depropagation is significant. Although a general mathematical treatment of the terminal model with depropagation was established in the 1980s, a penultimate model and higher-order terminal models with depropagation have not been systematically studied, since depropagation leads to hierarchically-coupled and unclosed kinetic equations which are hard to solve analytically. In this work, we propose a truncation method to solve the steady-state kinetic equations of any-order terminal models with depropagation in a unified way, by reducing them into closed steady-state equations which give the exact solution of the original kinetic equations. Based on the steady-state equations, we also derive a general thermodynamic equality in which the Shannon entropy of the copolymer sequence is explicitly introduced as part of the free energy dissipation of the whole copolymerization system.

  20. The use of polydisulfides and copolymeric disulfides in the Li/PEO/SRPE battery system

    SciTech Connect

    Doeff, M.M.; Lerner, M.M.; Visco, S.J.; DeJonghe, L.C. )

    1982-08-01

    This paper reports that solid redox polymerization electrodes (SRPEs) have recently been used successfully as cathodes in lithium solid polymer electrolyte batteries. SRPEs contain organopolydisulfides (SRS) as the electroactive material; upon cell discharge these materials are reductively depolymerized via scission of the disulfide linkages to di- or trithiolate salts. The thiolate slats are reoxidized to the polymeric disulfides when the cell is recharged. Organopolydisulfides are easily synthesized via a one-step process, are inexpensive, and exhibit high performance levels in batteries. A characteristic unique to the ability to combine the desirable features of several compounds by copolymerization. The discharge characteristics of several different polymeric and copolymeric disulfides are presented in this paper. In general aliphatic organopoly-disulfides exhibit a flat discharge potential of about 2 V vs. Li, while other have higher cell voltages. The low equivalent weight and the high utilization of thick cathodes of-(SCH[sub 2]CH[sub 2]S)[sub n](X8) translate into high energy densities for lithium polymer electrolytes cells.

  1. Evolution of composition, molar mass, and conductivity during the free radical copolymerization of polyelectrolytes.

    PubMed

    Alb, Alina M; Paril, Ahmet; Catalgil-Giz, Huceste; Giz, Ahmet; Reed, Wayne F

    2007-07-26

    Despite their importance in biological and technological contexts, copolymeric polyelectrolytes (or "copolyelectrolytes") continue to present challenges to theorists and experimentalists. The first results of a unified approach to the kinetics and mechanisms of copolyelectrolyte synthesis and the physical characteristics of the resulting polymers are presented. The free radical copolymerization of 4-vinylbenzenesulfonic acid sodium salt and acrylamide was monitored using automatic continuous online monitoring of polymerization reactions (ACOMP), from which the average bivariate composition and mass distributions were determined. Composition drift was related to the evolution of conductivity. In some cases bimodal populations of copolyelectrolyte and homopolymeric poly(acrylamide) resulted, i.e., blends of copolyelectrolyte and neutral homopolymer. The end-product scattering behavior depended on whether the end-product was bimodal or not, as demonstrated using automatic continuous mixing (ACM) in conjunction with light scattering and viscosity. Negative light-scattering third virial coefficients were found for bimodal end-products. This combined approach may allow connecting the synthesis kinetics to the resulting "trivariate" distribution of composition, molar mass, and linear charge density, which in turn controls the properties of end-product solutions, such as chain conformations, interparticle interactions, viscosity, interactions with colloids and other polymers, phase separation, etc. Unified results may allow testing and improvement of existing polyelectrolyte theories, development of new quantitative physicochemical models, provide advanced characterization methods, set the stage for studying more complex copolyelectrolytes, such as hydrophobically modified ones, and provide tools for ultimately controlling and tailoring the synthesis and properties of copolyelectrolytes.

  2. Performance of automatic scanning microscope for nuclear emulsion experiments

    NASA Astrophysics Data System (ADS)

    Güler, A. Murat; Altınok, Özgür

    2015-12-01

    The impressive improvements in scanning technology and methods let nuclear emulsion to be used as a target in recent large experiments. We report the performance of an automatic scanning microscope for nuclear emulsion experiments. After successful calibration and alignment of the system, we have reached 99% tracking efficiency for the minimum ionizing tracks that penetrating through the emulsions films. The automatic scanning system is successfully used for the scanning of emulsion films in the OPERA experiment and plan to use for the next generation of nuclear emulsion experiments.

  3. Performance of automatic scanning microscope for nuclear emulsion experiments

    SciTech Connect

    Güler, A. Murat; Altınok, Özgür

    2015-12-31

    The impressive improvements in scanning technology and methods let nuclear emulsion to be used as a target in recent large experiments. We report the performance of an automatic scanning microscope for nuclear emulsion experiments. After successful calibration and alignment of the system, we have reached 99% tracking efficiency for the minimum ionizing tracks that penetrating through the emulsions films. The automatic scanning system is successfully used for the scanning of emulsion films in the OPERA experiment and plan to use for the next generation of nuclear emulsion experiments.

  4. [Perfluorocarbon emulsions and other corpuscular systems influence on neutrophil activity].

    PubMed

    Shekhtman, D G; Safronova, V G; Sklifas, A N; Alovskaia, A A; Gapeev, A B; Obraztsov, V V; Chemeris, N K

    1997-01-01

    Influence of perfluorodecalin, perfluoromethilcyclohexylpiperidine, perfluorotributylamine emulsions on active oxygen form (AOF) generation by neutrophils has been studied. All investigated emulsions stabilized both proxanol 268 and egg yolk phospholipids inhibited PMA-stimulated neutrophil activity. Castor oil emulsion also inhibited the neutrophil activity. Neutrophil response for chemotactic peptide, was unchanged in the presence of all tested emulsions. We suppose that fast hydrophobic attachment of inert submicrone emulsion particles to cell surface provokes alteration of neutrophil plasma membrane function resulting in a decrease of AOF generation. PMID:9490112

  5. Emulsions stabilised by whey protein microgel particles: towards food-grade Pickering emulsions.

    PubMed

    Destribats, Mathieu; Rouvet, Martine; Gehin-Delval, Cécile; Schmitt, Christophe; Binks, Bernard P

    2014-09-28

    We have investigated a new class of food-grade particles, whey protein microgels, as stabilisers of triglyceride-water emulsions. The sub-micron particles stabilized oil-in-water emulsions at all pH with and without salt. All emulsions creamed but exhibited exceptional resistance to coalescence. Clear correlations exist between the properties of the microgels in aqueous dispersion and the resulting emulsion characteristics. For conditions in which the particles were uncharged, fluid emulsions with relatively large drops were stabilised, whereas emulsions stabilized by charged particles contained smaller flocculated drops. A combination of optical microscopy of the drops and spectrophotometry of the resolved aqueous phase allowed us to estimate the interfacial adsorption densities of the particles using the phenomenon of limited coalescence. We deduce two classes of particle arrangement. Complete adsorption of the particles was obtained when they were neutral or when their charges were screened by salt resulting in at least one particle monolayer at the interface. By contrast, only around 50% of the particles adsorbed when they were charged with emulsion drops being covered by less than half a monolayer. These findings were supported by direct visualization of drop interfaces using cryo-scanning electron microscopy. Uncharged particles were highly aggregated and formed a continuous 2-D network at the interface. Otherwise particles organized as individual aggregates separated by particle-free regions. In this case, we suggest that some particles spread at the interface leading to the formation of a continuous protein membrane. Charged particles displayed the ability to bridge opposing interfaces of neighbouring drops to form dense particle disks protecting drops against coalescence; this is the main reason for the flocculation and stability of emulsions containing sparsely covered drops.

  6. Evaporation from an ionic liquid emulsion.

    PubMed

    Friberg, Stig E

    2007-03-15

    The conditions during evaporation in a liquid crystal-in-ionic liquid microemulsion (LC/microEm) were estimated using the phase diagram of the system. The equations for selected tie lines were established and the coordinates calculated for the sites, at which the evaporation lines crossed the tie lines. These values combined with the coordinates for the phases connecting the tie lines were used to calculate the amounts and the composition of the fractions of the two phases present in the emulsion during the evaporation. One of the emulsion phases was a lamellar liquid crystal and high energy emulsification would lead to the liquid crystal being disrupted to form vesicles. Such a system tenders a unique opportunity to study the interaction between vesicles and normal micelles, which gradually change to inverse micelles over bi-continuous structures. The amount of vesicles in the liquid phase versus the fraction liquid crystal was calculated for two extreme cases of vesicle core size and shell thickness. The limit of evaporation while retaining the vesicle structure was calculated for emulsions of different original compositions assuming the minimum continuous liquid phase to be 50% of the emulsion.

  7. Evaporation from an ionic liquid emulsion.

    PubMed

    Friberg, Stig E

    2007-03-15

    The conditions during evaporation in a liquid crystal-in-ionic liquid microemulsion (LC/microEm) were estimated using the phase diagram of the system. The equations for selected tie lines were established and the coordinates calculated for the sites, at which the evaporation lines crossed the tie lines. These values combined with the coordinates for the phases connecting the tie lines were used to calculate the amounts and the composition of the fractions of the two phases present in the emulsion during the evaporation. One of the emulsion phases was a lamellar liquid crystal and high energy emulsification would lead to the liquid crystal being disrupted to form vesicles. Such a system tenders a unique opportunity to study the interaction between vesicles and normal micelles, which gradually change to inverse micelles over bi-continuous structures. The amount of vesicles in the liquid phase versus the fraction liquid crystal was calculated for two extreme cases of vesicle core size and shell thickness. The limit of evaporation while retaining the vesicle structure was calculated for emulsions of different original compositions assuming the minimum continuous liquid phase to be 50% of the emulsion. PMID:17207810

  8. Surface active agent for emulsion fuel

    SciTech Connect

    Aoki, Y.; Furuyama, Y.; Moriyama, N.

    1980-01-08

    A method is claimed for preparing a water-in-oil emulsion fuel which comprises emulsifying water in oil, in the presence of an emulsifying agency. The improvement comprises using as the emulsifying agent, a surfactant. The formula of this surfactant is presented.

  9. How does oil type determine emulsion characteristics in concentrated Na-caseinate emulsions?

    PubMed

    Tan, Hui Lin; McGrath, Kathryn M

    2013-08-01

    Macroscopic properties and ensemble average diffusion of concentrated (dispersed phase 50-60 wt%) Na-caseinate-stabilised emulsions for three different oils (soybean oil, palm olein and tetradecane) were explored. On a volume fraction basis, pulsed gradient stimulated echo (PGSTE)-NMR data show that droplet dynamics for all three systems are similar within a region of the emulsion morphology diagram. The exact limits of the emulsion space depend however on which oil is considered. The reduced solubility of tetradecane in water, and Na-caseinate in tetradecane, result in the stabilisation of flocs during formulation. Floc formation is not observed when soybean oil or palm olein is used under identical emulsion formulation conditions. Linear rheology experiments provide indirect evidence that the local structure and the properties of the thin film interfacial domain of tetradecane emulsions vary from those of soybean oil and palm olein emulsions. Collectively these data indicate that protein/oil interactions within a system dominate over specific oil droplet structure and size distribution, which are similar in the three systems. PMID:23683496

  10. Particle-Stabilized Powdered Water-in-Oil Emulsions.

    PubMed

    Binks, Bernard P; Tyowua, Andrew T

    2016-04-01

    The preparation of powdered water-in-oil (w/o) emulsions by gentle aeration of w/o emulsions stabilized by hydrophobic fumed silica particles in the presence of oleophobic fluorinated clay particles is reported for an alkane and a triglyceride oil. The resultant powders consist of water drops dispersed in oil globules themselves dispersed in air (w/o/a). They contain ∼80 wt % of the precursor w/o emulsion and were stable to phase separation for over 1 year but release oil and water when sheared on a substrate. Above a certain ratio of w/o emulsion:fluorinated clay particles, the powdered emulsions partially invert to an emulsion paste, composed of air bubbles and water droplets dispersed in oil. The tap density and angle of repose of the powdered emulsions were measured and compared with those of the corresponding powdered oils making up the continuous phase of the precursor emulsions. The contact angles of water droplets under oil on glass slides spin coated with silica particles and oil drops and w/o emulsion droplets in air on compressed disks of fluorinated clay particles are consistent with the stabilization of w/o emulsions and powdered emulsions, respectively. PMID:27002604

  11. Pickering w/o emulsions: drug release and topical delivery.

    PubMed

    Frelichowska, Justyna; Bolzinger, Marie-Alexandrine; Valour, Jean-Pierre; Mouaziz, Hanna; Pelletier, Jocelyne; Chevalier, Yves

    2009-02-23

    The skin absorption from Pickering emulsions as a new dosage form was investigated for the first time. Pickering emulsions are stabilized by adsorbed solid particles instead of emulsifier molecules. They are promising dosage forms that significantly differ from classical emulsions within several features. The skin permeation of a hydrophilic model penetrant (caffeine) was investigated from a w/o Pickering emulsion and compared to a w/o classical emulsion stabilized with an emulsifier. Both emulsions had the same composition and physicochemical properties in order to focus on the effect of the interfacial layer on the drug release and skin absorption processes. The highest permeation rates were obtained from the Pickering emulsion with a pseudo-steady state flux of 25 microg cm(-2)h(-1), threefold higher than from a classical emulsion (9.7 microg cm(-2)h(-1)). After 24h exposure, caffeine was mostly in the receptor fluid and in the dermis; cumulated amounts of caffeine were higher for the Pickering emulsion. Several physicochemical phenomena were investigated for clearing up the mechanisms of enhanced permeation from the Pickering emulsion. Among them, higher adhesion of Pickering emulsion droplets to skin surface was disclosed. The transport of caffeine adsorbed on silica particles was also considered relevant since skin stripping showed that aggregates of silica particles entered deeply the stratum corneum.

  12. Particle-Stabilized Powdered Water-in-Oil Emulsions.

    PubMed

    Binks, Bernard P; Tyowua, Andrew T

    2016-04-01

    The preparation of powdered water-in-oil (w/o) emulsions by gentle aeration of w/o emulsions stabilized by hydrophobic fumed silica particles in the presence of oleophobic fluorinated clay particles is reported for an alkane and a triglyceride oil. The resultant powders consist of water drops dispersed in oil globules themselves dispersed in air (w/o/a). They contain ∼80 wt % of the precursor w/o emulsion and were stable to phase separation for over 1 year but release oil and water when sheared on a substrate. Above a certain ratio of w/o emulsion:fluorinated clay particles, the powdered emulsions partially invert to an emulsion paste, composed of air bubbles and water droplets dispersed in oil. The tap density and angle of repose of the powdered emulsions were measured and compared with those of the corresponding powdered oils making up the continuous phase of the precursor emulsions. The contact angles of water droplets under oil on glass slides spin coated with silica particles and oil drops and w/o emulsion droplets in air on compressed disks of fluorinated clay particles are consistent with the stabilization of w/o emulsions and powdered emulsions, respectively.

  13. Stimuli-Sensitive Composite Microgels

    NASA Astrophysics Data System (ADS)

    Kawaguchi, Haruma

    Poly(N-isopropylacrylamide) (PNIPAM) microgels were prepared by precipitation polymerization and PNIPAM shell / hard core particles were obtained by soap-free emulsion copolymerization or seeded polymerization. Hairy particles were prepared by “grafting-to” modification or “grafting-from” living radical polymerization. They exhibited not only volume phase transition but also changes in some physical properties in a certain temperature range. Composite thermosensitive microgels including magnetite, Au, or titania were obtained by in situ formation of metal or metal oxide in polymeric particles. The functions of metal or metal oxide were tuned by reversible volume phase transition of the microgel as a function of temperature. Enzyme-carrying thermosensitive microgels exhibited unique temperature-dependence of enzyme activity.

  14. [The enhancement effect of emulsion in flame atomic absorption spectrometry].

    PubMed

    Liu, Li-hang; Shen, Chun-yu

    2002-08-01

    A enhancement method of FAAS with emulsion as enhancement agent has been developed. The enhancement effect of emulsion made of three organic solvents (benzene, benzene-propanone, xylene), one organic reagent (dibutyl phthalate) and three emulsifiers (Tween-80, Triton X-100, OP) for iron, nickel, zinc, manganese and lead was studied. The results indicated that the enhancement is satisfactory. The emulsion with maximum enhancement percentage are respectively emulsion of benzene-OP-dibutyl phthalate with 89%, emulsion of xylene-Trition-100-dibutyl phthal with 34%, emulsion of benzene-Trition-100 with 121%, emulsion of benzene-Trition-100-dibutyl phthalate with 38% and 69% in sequence of the above elements. PMID:12938401

  15. 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.

  16. Stabilization of perflubron emulsions with egg yolk phospholipid.

    PubMed

    Pelura, T J; Johnson, C S; Tarara, T E; Weers, J G

    1992-01-01

    Egg Yolk Phospholipid(EYP) has been used extensively as the primary surfactant in parenteral fat emulsions for many years. The simplicity, functionality and physiologic tolerance of EYP has contributed greatly to its success in the intravenous emulsion arena. The mechanism of stabilization in triglyceride emulsions is well understood; however, this is not the case with perfluorocarbon emulsions. Interfacial models, as well as emulsion stability studies, have been conducted utilizing EYP of varied composition in order to derive a structure/function relationship. Our studies indicate that minor components, total unsaturation, acyl chain length and presence of charged species have significant impact on the functional properties of EYP and the subsequent stability of the emulsion product. These findings contribute to our ability to design and manipulate natural surfactants with superior properties for use in medical applications of perfluorocarbon emulsions. PMID:1391521

  17. Showing Emulsion Properties with Common Dairy Foods

    NASA Astrophysics Data System (ADS)

    Bravo-Diaz, Carlos; Gonzalez-Romero, Elisa

    1996-09-01

    Foods are mixtures of different chemical compounds, and the quality we sense (taste, texture, color, etc.) are all manifestations of its chemical properties. Some of them can be visualized with the aid of simple, safe and inexpensive experiments using dairy products that can be found in any kitchen and using almost exclusively kitchen utensils. In this paper we propose some of them related with food emulsions. Food emulsions cover an extremely wide area of daily-life applications such as milk, sauces, dressings and beverages. Experimentation with some culinary recipes to prepare them and the analyisis of the observed results is close to ideal subject for the introduction of chemical principles, allowing to discuss about the nature and composition of foods, the effects of additives, etc. At the same time it allows to get insights into the scientific reasons that underlie on the recipes (something that it is not usually found in most cookbooks). For example, when making an emulsion like mayonnaise, why the egg yolks and water are the first materials in the bowl , and the oil is added to them rather than in the other way around? How you can "rescue" separate emulsions (mayonnaise)? Which parameters affect emulsion stability? Since safety, in its broad sense, is the first requisite for any food, concerns about food exist throughout the world and the more we are aware of our everyday life, the more likely we will be to deal productively with the consequences. On the other hand, understanding what foods are and how cooking works destroys no delightful mystery of the art of cuisine, instead the mystery expands.

  18. 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

  19. Alternating copolymerization of dihydrocoumarin and epoxides catalyzed by chromium salen complexes: a new route to functional polyesters.

    PubMed

    Van Zee, Nathan J; Coates, Geoffrey W

    2014-06-18

    We report the alternating ring-opening copolymerization of dihydrocoumarin with epoxides catalyzed by chromium(III) salen complexes. This process provides access to a range of perfectly alternating polyesters with high molecular weights and narrow molecular weight distributions. Atactic poly(cyclohexene dihydrocoumarate) and poly(cyclopentene dihydrocoumarate) were found to be semi-crystalline by differential scanning calorimetry.

  20. Radiation synthesis of temperature-responsive hydrogels by copolymerization of [2-(methacryloyloxy)ethyl]trimethylammonium chloride with /N-isopropylacrylamide

    NASA Astrophysics Data System (ADS)

    Mun, Grigoriy A.; Nurkeeva, Zauresh S.; Khutoryanskiy, Vitaliy V.; Sergaziyev, Aibek D.; Rosiak, Janusz M.

    2002-08-01

    Novel cationic hydrogels were synthesized by γ-irradiation copolymerization of [2-(methacryloyloxy)ethyl]trimethylammonium chloride with N-isopropylacrylamide in the presence of cross-linking agent. The synthesis regularities have been studied. The swelling behavior of hydrogels as a function of copolymers composition and temperature was evaluated.

  1. Efficient catalyst removal and recycling in copolymerization of epoxides with carbon dioxide via simple liquid-liquid phase separation.

    PubMed

    Nakano, Koji; Fujie, Ryuhei; Shintani, Ryo; Nozaki, Kyoko

    2013-10-18

    A simple and efficient catalyst removal system has been developed in the cobalt-salen-catalyzed copolymerization of propylene oxide with carbon dioxide. The present system requires no prior modification of the catalyst, and the removal is achieved by simple addition of myristic acid, followed by organic liquid-liquid phase separation.

  2. Histidine residues in the peptide D-Lys(6)-GnRH: potential for copolymerization in polymeric nanoparticles.

    PubMed

    Kafka, Alexandra P; Kleffmann, Torsten; Rades, Thomas; McDowell, Arlene

    2009-01-01

    Poly(ethylcyanoacrylate) (PECA) nanoparticles containing the bioactive d-Lys(6)-GnRH were manufactured by an in situ interfacial polymerization process using a w/o-microemulsion template containing the peptide in the dispersed aqueous pseudophase of the microemulsion. Polymeric nanoparticles were characterized using PCS, RP-HPLC (bulk level) and MALDI TOF mass spectrometry (molecular level). The peptide d-Lys(6)-GnRH was reactive with the alkylcyanoacrylate monomer, resulting in some of the peptide copolymerizing with the monomer. MALDI TOF/TOF (tandem) analysis revealed that the histidine residue in position 2 of d-Lys(6)-GnRH interacts covalently in the polymerization process. A reaction mechanism for this nucleophilic interference is suggested. The copolymerization reaction appeared to occur within seconds after the addition of the monomer to the microemulsion. The surface charge of resulting nanoparticles was less negative (-3 mV) compared with the zeta potential of empty nanoparticles (-27.5 mV). The copolymerization yielded high entrapment rates of 95 +/- 4% of peptide, but showed limited release ( approximately 11%) of free peptide over 5 days. A separate experiment demonstrated that the addition of d-Lys(6)-GnRH to preformed empty PECA nanoparticles (ex situ) also yielded fractions of copolymerized peptide suggesting a certain proportion of polymer remains available for copolymerization possibly through an unzipping depolymerization/repolymerization process. Therefore, the reactivity of histidine residues in bioactives needs to be considered whenever using the bioactive in situ or ex situ with polymeric PECA nanoparticles.

  3. Design of highly active binary catalyst systems for CO2/epoxide copolymerization: polymer selectivity, enantioselectivity, and stereochemistry control.

    PubMed

    Lu, Xiao-Bing; Shi, Lei; Wang, Yi-Ming; Zhang, Rong; Zhang, Ying-Ju; Peng, Xiao-Jun; Zhang, Zhi-Chao; Li, Bo

    2006-02-01

    Asymmetric, regio- and stereoselective alternating copolymerization of CO(2) and racemic aliphatic epoxides proceeds effectively under mild temperature and pressure by using a binary catalyst system of a chiral tetradentate Schiff base cobalt complex [SalenCo(III)X] as the electrophile in conjunction with an ionic organic ammonium salt or a sterically hindered strong organic base as the nucleophile. The substituent groups on the aromatic rings, chiral diamine backbone, and axial X group of the electrophile, as well as the nucleophilicity, leaving ability, and coordination ability of the nucleophile, all significantly affect the catalyst activity, polymer selectivity, enantioselectivity, and stereochemistry. A bulky chiral cyclohexenediimine backbone complex [SalcyCo(III)X] with an axial X group of poor leaving ability as the electrophile, combined with a bulky nuclephile with poor leaving ability and low coordination ability, is an ideal binary catalyst system for the copolymerization of CO(2) and a racemic aliphatic epoxide to selectively produce polycarbonates with relatively high enantioselectivity, >95% head-to-tail connectivity, and >99% carbonate linkages. A fast copolymerization of CO(2) and epoxides was observed when the concentration of the electrophile or/and the nucleophile was increased, and the number of polycarbonate chains was proportional to the concentration of the nucleophile. Electrospray ionization mass spectrometry, in combination with a kinetic study, showed that the copolymerization involved the coordination activation of the monomer by the electrophile and polymer chain growth predominately occurring in the nucleophile. Both the enantiomorphic site effect resulting from the chiral electrophile and the polymer chain end effect mainly from the bulky nucleophile cooperatively control the stereochemistry of the CO(2)/epoxide copolymerization.

  4. Controlled graft copolymerization of lactic acid onto starch in a supercritical carbon dioxide medium.

    PubMed

    Salimi, Kouroush; Yilmaz, Mehmet; Rzayev, Zakir M O; Piskin, Erhan

    2014-12-19

    This work presents a new approach for the synthesis of a starch-g-poly L-lactic acid (St-g-PLA) copolymer via the graft copolymerization of LA onto starch using stannous 2-ethyl hexanoate (Sn(Oct)2) as a catalyst in a supercritical carbon dioxide (scCO2) medium. The effects of several process parameters, including the pressure, temperature, scCO2 flow rate and reaction time, on the polymerization yield and grafting degree were studied. Amorphous graft St-g-PLA copolymers with increased thermal stability and processability were produced with a high efficiency. The maximum grafting degree (i.e., 52% PLA) was achieved with the following reaction conditions: 6h, 100°C, 200 bar and a 1:3 (w/w) ratio of St/LA. It was concluded that these low cost biobased graft biopolymers are potential candidates for several environment-friendly applications.

  5. Crystalline Isotactic Polar Polypropylene from the Palladium-Catalyzed Copolymerization of Propylene and Polar Monomers.

    PubMed

    Ota, Yusuke; Ito, Shingo; Kobayashi, Minoru; Kitade, Shinichi; Sakata, Kazuya; Tayano, Takao; Nozaki, Kyoko

    2016-06-20

    Moderately isospecific homopolymerization of propylene and the copolymerization of propylene and polar monomers have been achieved with palladium complexes bearing a phosphine-sulfonate ligand. Optimization of substituents on the phosphorus atom of the ligand revealed that the presence of bulky alkyl groups (e.g. menthyl) is crucial for the generation of high-molecular-weight polypropylenes (Mw ≈10(4) ), and the substituent at the ortho-position relative to the sulfonate group influences the molecular weight and isotactic regularity of the obtained polypropylenes. Statistical analysis suggested that the introduction of substituents at the ortho-position relative to the sulfonate group favors enantiomorphic site control over chain end control in the chain propagation step. The triad isotacticity could be increased to mm=0.55-0.59, with formation of crystalline polar polypropylenes, as supported by the presence of melting points and sharp peaks in the corresponding X-ray diffraction patterns. PMID:27161896

  6. Block Copolymerization of Lactide and an Epoxide Facilitated by a Redox Switchable Iron-Based Catalyst.

    PubMed

    Biernesser, Ashley B; Delle Chiaie, Kayla R; Curley, Julia B; Byers, Jeffery A

    2016-04-18

    A cationic iron(III) complex was active for the polymerization of various epoxides, whereas the analogous neutral iron(II) complex was inactive. Cyclohexene oxide polymerization could be "switched off" upon in situ reduction of the iron(III) catalyst and "switched on" upon in situ oxidation, which is orthogonal to what was observed previously for lactide polymerization. Conducting copolymerization reactions in the presence of both monomers resulted in block copolymers whose identity can be controlled by the oxidation state of the catalyst: selective lactide polymerization was observed in the iron(II) oxidation state and selective epoxide polymerization was observed in the iron(III) oxidation state. Evidence for the formation of block copolymers was obtained from solubility differences, GPC, and DOSY-NMR studies. PMID:26991820

  7. Graft copolymerization of ethyl acrylate onto tamarind kernel powder, and evaluation of its biodegradability.

    PubMed

    del Real, Alicia; Wallander, Daniela; Maciel, Alfredo; Cedillo, Gerardo; Loza, Herminia

    2015-03-01

    In the present study, tamarind kernel powder and ethyl acrylate were reacted by free radical polymerization to synthesize a grafted copolymer soluble in water. The grafted copolymer was analyzed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR); FTIR showed a shift of the vibration of R-CO-OR' from 1258 cm(-1) to 1253 cm(-1). This shift appeared because of the grafting copolymerization. Films were prepared to study the mechanical properties and the biodegradation of this material. The mechanical properties of the grafted copolymer were found to lie between those of the parent polymers, suitable for disposable products. The new grafted copolymer manifested a steady process of biodegradation under incubation with the bacterial strain Alicycliphilus sp. BQ1; this was proved by scanning electron microscopy (SEM) and near infrared spectroscopy (NIR).

  8. Controlled graft copolymerization of lactic acid onto starch in a supercritical carbon dioxide medium.

    PubMed

    Salimi, Kouroush; Yilmaz, Mehmet; Rzayev, Zakir M O; Piskin, Erhan

    2014-12-19

    This work presents a new approach for the synthesis of a starch-g-poly L-lactic acid (St-g-PLA) copolymer via the graft copolymerization of LA onto starch using stannous 2-ethyl hexanoate (Sn(Oct)2) as a catalyst in a supercritical carbon dioxide (scCO2) medium. The effects of several process parameters, including the pressure, temperature, scCO2 flow rate and reaction time, on the polymerization yield and grafting degree were studied. Amorphous graft St-g-PLA copolymers with increased thermal stability and processability were produced with a high efficiency. The maximum grafting degree (i.e., 52% PLA) was achieved with the following reaction conditions: 6h, 100°C, 200 bar and a 1:3 (w/w) ratio of St/LA. It was concluded that these low cost biobased graft biopolymers are potential candidates for several environment-friendly applications. PMID:25263875

  9. Structural and behavioral characteristics of radiolytically synthesized polyacrylic acid-polyacrylonitrile copolymeric hydrogels

    NASA Astrophysics Data System (ADS)

    Bera, Anuradha; Misra, R. K.; Singh, Shailendra K.

    2013-10-01

    Copolymeric hydrogels of polyacrylic acid (PAA) - polyacrylonitrile (PAN) was radiolytically synthesized from their respective monomers with trimethyloltrimethacrylate (TMPTMA) as the crosslinker wherein both polymerization and crosslinking could be achieved in a single step reaction using 60Co γ-radiation under varying doses and dose rates. The formation of the hydrogels was confirmed by their FT-IR analysis, while their thermal degradation patterns were investigated through thermogravimetric analysis in both the dry and swelled state. The water sorption studies showed rapid swelling behavior of these hydrogels, where swelling (%EWC) was found to be strongly dependent on the ratio of the two monomers in the hydrogels and the swelling kinetics dependent on the dose rates of hydrogel synthesis. These radiolytically synthesized hydrogels responded to electrical stimulus both in terms of the bending speed as well as bending angle under an applied voltage. The nature of the deformation was reversible and can be controlled through switching the voltage on and off.

  10. Block Copolymerization of Lactide and an Epoxide Facilitated by a Redox Switchable Iron-Based Catalyst.

    PubMed

    Biernesser, Ashley B; Delle Chiaie, Kayla R; Curley, Julia B; Byers, Jeffery A

    2016-04-18

    A cationic iron(III) complex was active for the polymerization of various epoxides, whereas the analogous neutral iron(II) complex was inactive. Cyclohexene oxide polymerization could be "switched off" upon in situ reduction of the iron(III) catalyst and "switched on" upon in situ oxidation, which is orthogonal to what was observed previously for lactide polymerization. Conducting copolymerization reactions in the presence of both monomers resulted in block copolymers whose identity can be controlled by the oxidation state of the catalyst: selective lactide polymerization was observed in the iron(II) oxidation state and selective epoxide polymerization was observed in the iron(III) oxidation state. Evidence for the formation of block copolymers was obtained from solubility differences, GPC, and DOSY-NMR studies.

  11. Graft copolymerization of ethyl acrylate onto tamarind kernel powder, and evaluation of its biodegradability.

    PubMed

    del Real, Alicia; Wallander, Daniela; Maciel, Alfredo; Cedillo, Gerardo; Loza, Herminia

    2015-03-01

    In the present study, tamarind kernel powder and ethyl acrylate were reacted by free radical polymerization to synthesize a grafted copolymer soluble in water. The grafted copolymer was analyzed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR); FTIR showed a shift of the vibration of R-CO-OR' from 1258 cm(-1) to 1253 cm(-1). This shift appeared because of the grafting copolymerization. Films were prepared to study the mechanical properties and the biodegradation of this material. The mechanical properties of the grafted copolymer were found to lie between those of the parent polymers, suitable for disposable products. The new grafted copolymer manifested a steady process of biodegradation under incubation with the bacterial strain Alicycliphilus sp. BQ1; this was proved by scanning electron microscopy (SEM) and near infrared spectroscopy (NIR). PMID:25498603

  12. Inverse opal pH sensors with various protic monomers copolymerized with polyhydroxyethylmethacrylate hydrogel.

    PubMed

    Shin, Jinsub; Han, Sung Gu; Lee, Wonmok

    2012-11-01

    pH sensitive inverse opal sensors were synthesized using various vinyl monomers containing acidic or basic substituents. Acrylic acid (AA), vinylphosphonic acid (VPA), vinylimidazole (VI), and dimethylaminoethylmethacrylic acid (DMAEMA) were respectively copolymerized with hydroxyethylmethacrylate (HEMA), the building block monomer of the hydrogel via UV-initiated photopolymerization. Opal templating and subsequent template removal enabled the fabrication of four inverse opal (IO) hydrogel colorimetric sensors, which responded to pH in different fashions. pH-dependent swelling of the IO hydrogel induced the red-shift of the diffracted color. The sensors containing AA or VPA, the proton donating monomers showed the color shifts from green to red with pH increase due to the increased concentration of carboxylate anions bound to the hydrogel. Diprotic VPA sensor exhibited two-step increases of diffracted wavelengths at its pK(a1) and pK(a2) respectively. The sensors containing proton acceptors, VI and DMAEMA showed the pH-dependent color changes in an opposite way to the AA sensor and the VPA sensor since their ionizations take place by lowering pH due to the protonation at the amino groups. The shapes of pH response curves of VI and DMAEMA sensors were similar but pK(b)s were different from each other. Optical diffraction responses of four sensors were compared with the calculated concentration ratios of the ionized species to the total monomer with pH variation, and a deswelling effect in the vicinities of pK(a)s of phosphate buffer on the swelling response could be explained by shrinkage of PHEMA hydrogel under high ionic environment. In addition, copolymerization of AA, VPA and HEMA was carried out which resulted in a pH sensor exhibiting a wider range of pH for color change.

  13. Ultrasonication-assisted preparation and characterization of emulsions and emulsion gels for topical drug delivery.

    PubMed

    Singh, Vinay K; Behera, Baikuntha; Pramanik, Krishna; Pal, Kunal

    2015-03-01

    The current study describes the use of ultrasonication for the preparation of biphasic emulsions and emulsion gels for topical drug delivery. Sorbitan monostearate (SMS) was used as the surfactant for stabilizing the interface of sesame oil (apolar phase) and water (polar phase). Emulsions were formed at lower concentrations of SMS, whereas emulsion gels were formed at higher concentrations of SMS. The formulations were characterized by fluorescent microscopy, X-ray diffraction, viscosity, stress relaxation, spreadability, and differential scanning calorimetry studies. Fluorescence microscopy suggested formation of oil-in-water type of formulations. There was an increase in the viscosity, bulk resistance, and firmness of the formulations as the proportions of SMS was increased. The emulsion gels were viscoelastic in nature. Thermal studies suggested higher thermodynamic stability at higher proportions of either SMS or water. Metronidazole, a model antimicrobial drug, was incorporated within the formulations. The release of the drug from the formulations was found to be diffusion mediated. The drug-loaded formulations showed sufficient antimicrobial efficiency to be used as carriers for topical antimicrobial drug delivery. PMID:25470664

  14. Droplet Dynamics of a Flowing Emulsion System

    NASA Astrophysics Data System (ADS)

    Cypull, Olivia; Feitosa, Klebert

    The inner workings of glassy systems have long been a topic of interest for soft material scientists. Similarities between the jamming behavior of emulsions and the glass transition of glassy systems have prompted the conjecture that they might share the same underlying mechanism. Here we study a dense oil-in-water emulsion system forced to flow through a narrow microchannel. By matching the index of refraction of the two phases, we image the internal dynamics of the droplets in a confocal microscope. At low velocity speeds, we find that the velocity along the edge of the microchannel was not significantly different than then the average droplet velocity in the bulk suggesting a near plug flow. By contrast the droplets near the edge experienced more movement perpendicular to the flow indicating the fluidization effect of the confining walls.

  15. Heavy crude oils/particle stabilized emulsions.

    PubMed

    Kralova, Iva; Sjöblom, Johan; Øye, Gisle; Simon, Sébastien; Grimes, Brian A; Paso, Kristofer

    2011-12-12

    Fluid characterization is a key technology for success in process design for crude oil mixtures in the future offshore. In the present article modern methods have been developed and optimized for crude oil applications. The focus is on destabilization processes in w/o emulsions, such as creaming/sedimentation and flocculation/coalescence. In our work, the separation technology was based on improvement of current devices to promote coalescence of the emulsified systems. Stabilizing properties based on particles was given special attention. A variety of particles like silica nanoparticles (AEROSIL®), asphalthenes, wax (paraffin) were used. The behavior of these particles and corresponding emulsion systems was determined by use of modern analytical equipment, such as SARA fractionation, NIR, electro-coalescers (determine critical electric field), Langmuir technique, pedant drop technique, TG-QCM, AFM.

  16. Oil-based emulsion vaccine adjuvants.

    PubMed

    Schijns, Virgil E J C; Strioga, Marius; Ascarateil, Stephane

    2014-01-01

    Vaccine adjuvants are critical components in experimental and licensed vaccines used in human and veterinary medicine. When aiming to evoke an immune response to a purified antigen, the administration of antigen alone is often insufficient, unless the antigen contains microbial structures or has a natural particulate structure. In most cases, the rationale to use an adjuvant is obvious to the experimental immunologist or the professional vaccinologist, who is familiar with the nature of the antigen, and the aim of the vaccine to elicit a specific antibody response and/or a specific type of T cell response. In this unit, we describe protocols to formulate antigens with oil-based emulsions. Such emulsions represent a major prototype adjuvant category that is frequently used in experimental preclinical vaccines, as well as veterinary and human vaccines.

  17. Analytical applications of emulsions and microemulsions.

    PubMed

    Burguera, José Luis; Burguera, Marcela

    2012-07-15

    Dispersion systems like emulsions and microemulsions are able to solubilize both polar and non-polar substances due to the special arrangement of the oil and aqueous phases. The main advantages of using emulsions or microemulsions in analytical chemistry are that they do not require the previous destruction of the sample matrix or the use of organic solvents as diluents, and behave similarly to aqueous solutions, frequently allowing the use of aqueous standard solutions for calibration. However, it appears that there are many contradictory concepts and misunderstandings often related to terms definition when referring to such systems. The main aim of this review is to outline the differences between these two aggregates and to give an overview of the most recent advances on their analytical applications with emphasis on the potentiality of the on-line emulsification processes. PMID:22817921

  18. Heavy crude oils/particle stabilized emulsions.

    PubMed

    Kralova, Iva; Sjöblom, Johan; Øye, Gisle; Simon, Sébastien; Grimes, Brian A; Paso, Kristofer

    2011-12-12

    Fluid characterization is a key technology for success in process design for crude oil mixtures in the future offshore. In the present article modern methods have been developed and optimized for crude oil applications. The focus is on destabilization processes in w/o emulsions, such as creaming/sedimentation and flocculation/coalescence. In our work, the separation technology was based on improvement of current devices to promote coalescence of the emulsified systems. Stabilizing properties based on particles was given special attention. A variety of particles like silica nanoparticles (AEROSIL®), asphalthenes, wax (paraffin) were used. The behavior of these particles and corresponding emulsion systems was determined by use of modern analytical equipment, such as SARA fractionation, NIR, electro-coalescers (determine critical electric field), Langmuir technique, pedant drop technique, TG-QCM, AFM. PMID:22047991

  19. A comparative study of the physicochemical properties of a virgin coconut oil emulsion and commercial food supplement emulsions.

    PubMed

    Khor, Yih Phing; Koh, Soo Peng; Long, Kamariah; Long, Shariah; Ahmad, Sharifah Zarah Syed; Tan, Chin Ping

    2014-07-01

    Food manufacturers are interested in developing emulsion-based products into nutritional foods by using beneficial oils, such as fish oil and virgin coconut oil (VCO). In this study, the physicochemical properties of a VCO oil-in-water emulsion was investigated and compared to other commercial oil-in-water emulsion products (C1, C2, C3, and C4). C3 exhibited the smallest droplet size of 3.25 µm. The pH for the emulsion samples ranged from 2.52 to 4.38 and thus were categorised as acidic. In a texture analysis, C2 was described as the most firm, very adhesive and cohesive, as well as having high compressibility properties. From a rheological viewpoint, all the emulsion samples exhibited non-Newtonian behaviour, which manifested as a shear-thinning property. The G'G'' crossover illustrated by the VCO emulsion in the amplitude sweep graph but not the other commercial samples illustrated that the VCO emulsion had a better mouthfeel. In this context, the VCO emulsion yielded the highest zeta potential (64.86 mV), which was attributed to its strong repulsive forces, leading to a good dispersion system. C2 comprised the highest percentage of fat among all emulsion samples, followed by the VCO emulsion, with 18.44% and 6.59%, respectively.

  20. Emulsion characteristics, chemical and textural properties of meat systems produced with double emulsions as beef fat replacers.

    PubMed

    Serdaroğlu, Meltem; Öztürk, Burcu; Urgu, Müge

    2016-07-01

    In recent years, double emulsions are stated to have a promising potential in low-fat food production, however, there are very few studies on their possible applications in meat matrices. We aimed to investigate the quality of beef emulsion systems in which beef fat was totally replaced by double emulsions (W1/O/W2) prepared with olive oil and sodium caseinate (SC) by two-step emulsification procedure. Incorporation of W1/O/W2 emulsion resulted in reduced lipid, increased protein content, and modified fatty acid composition. W1/O/W2 emulsion treatments had lower jelly and fat separation, higher water-holding capacity and higher emulsion stability than control samples with beef fat. Increased concentrations of W1/O/W2 emulsions resulted in significant changes in texture parameters. TBA values were lower in W1/O/W2 emulsion treatments than control treatment after 60days of storage. In conclusion, our study confirms that double emulsions had promising impacts on modifying fatty acid composition and developing both technologically and oxidatively stable beef emulsion systems. PMID:26995773

  1. [Multiple emulsions; bioactive compounds and functional foods].

    PubMed

    Jiménez-Colmenero, Francisco

    2013-01-01

    The continued appearance of scientific evidence about the role of diet and/or its components in health and wellness, has favored the emergence of functional foods which currently constitute one of the chief factors driving the development of new products. The application of multiple emulsions opens new possibilities in the design and development of functional foods. Multiple emulsions can be used as an intermediate product (food ingredient) into technological strategies normally used in the optimization of the presence of bioactive compounds in healthy and functional foods. This paper presents a summary of the types, characteristics and formation of multiple emulsions, possible location of bioactive compounds and their potential application in the design and preparation of healthy and functional foods. Such applications are manifested particularly relevant in relation to quantitative and qualitative aspects of lipid material (reduced fat/calories and optimization of fatty acid profile), encapsulation of bioactive compounds mainly hydrophilic and sodium reduction. This strategy offers interesting possibilities regarding masking flavours and improving sensory characteristics of foods. PMID:24160194

  2. Simple and double emulsions via electrospray

    NASA Astrophysics Data System (ADS)

    Barrero, Antonio; Loscertales, Ignacio G.

    2005-11-01

    Generation of nanoemulsions is of great interest in medical and pharmaceutical applications; drug delivery or antiviral emulsions are typical examples. The use of electrosprays for dispersing liquids inside liquid insulator baths have been recently reported, (Barrero et al. J. Colloid Interf. Sci. 272, 104, 2004). Capsules, nanotubes and coaxial nanofibers have been obtained from electrified coaxial jets (Loscertales et al. Science 295, n. 5560, 1695, 2002; J. American Chem. Soc. 126, 5376, 2004). Here we present a method for making double emulsions (both water-oil-water and o/w/o) based on the generation of compound electrosprays inside insulator liquid baths. Basically, a conducting liquid injected throughout a capillary needle is electroatomized in cone-jet mode inside a dielectric liquid bath. A third insulating liquid is injected inside the Taylor cone to form a second meniscus. Then, a steady coaxial jet, in which the insulating liquid is coated by the conducting one, develops. A double emulsion forms as a result of the jet breaking up into compound droplets electrically charged. Experimental results carried out with glycerine and different oils in a bath of heptane are reported.

  3. [Multiple emulsions; bioactive compounds and functional foods].

    PubMed

    Jiménez-Colmenero, Francisco

    2013-01-01

    The continued appearance of scientific evidence about the role of diet and/or its components in health and wellness, has favored the emergence of functional foods which currently constitute one of the chief factors driving the development of new products. The application of multiple emulsions opens new possibilities in the design and development of functional foods. Multiple emulsions can be used as an intermediate product (food ingredient) into technological strategies normally used in the optimization of the presence of bioactive compounds in healthy and functional foods. This paper presents a summary of the types, characteristics and formation of multiple emulsions, possible location of bioactive compounds and their potential application in the design and preparation of healthy and functional foods. Such applications are manifested particularly relevant in relation to quantitative and qualitative aspects of lipid material (reduced fat/calories and optimization of fatty acid profile), encapsulation of bioactive compounds mainly hydrophilic and sodium reduction. This strategy offers interesting possibilities regarding masking flavours and improving sensory characteristics of foods.

  4. Evaluation on oxidative stability of walnut beverage emulsions.

    PubMed

    Liu, Shuang; Liu, Fuguo; Xue, Yanhui; Gao, Yanxiang

    2016-07-15

    Walnut beverage emulsions were prepared with walnut kernels, mixed nonionic emulsifiers and xanthan gum. The effects of food antioxidants on the physical stability and lipid oxidation of walnut beverage emulsions were investigated. The results showed that tea polyphenols could not only increase the droplet size of the emulsions, but also enhance physical stability during the thermal storage at 62 ± 1 °C. However, water-dispersed oil-soluble vitamin E and enzymatically modified isoquercitrin obviously decreased the physical stability of the emulsion system during the thermal storage. BHT and natural antioxidant extract had scarcely influenced on the physical stability of walnut beverage emulsions. Tea polyphenols and BHT could significantly retard lipid oxidation in walnut beverage emulsions against thermal and UV light exposure during the storage. Vitamin E exhibited the prooxidant effect during the thermal storage and the antioxidant attribute during UV light exposure. Other food antioxidants had no significant effect on retarding lipid oxidation during thermal or light storage.

  5. Turbulent flow of oil-water emulsions with polymer additives

    NASA Astrophysics Data System (ADS)

    Manzhai, V. N.; Monkam Clovis Le Grand, Monkam; Abdousaliamov, A. V.

    2014-08-01

    The article outlines direct and reverse oil-water emulsions. Microphotography study of these emulsions was carried out. The effect of water-soluble and oil soluble polymers on the emulsion structure and their turbulent flow velocity in cylindrical channel was investigated. It has been experimentally proven that if the fluid being transported is not homogeneous, but a two-phase oil-water emulsion, only the polymer that is compatible with dispersion medium and capable of dissolving in this medium can reduce the hydrodynamic resistance of the fluid flow. Thus, the resistance in direct emulsions can be reduced by water- soluble polyacrylamide, while oil-soluble polyhexene can be applied for reverse emulsions.

  6. [Carnol as a stabilizer of the emulsion I system].

    PubMed

    De Almeida Cunha, B C; Dini, M E

    1975-01-01

    "Carnol" insaponificable fraction from "chalky" carnauba wax, was tested for its emulsified system estabilizing abilities. The required HLB of test system, made up of mineral oil, water, polyoxyethylene sorbitan trioleate and sorbitam monooleate, was 9.0. 1% of carnol (w/v) formed A/O emulsions (HLB less than or equal to 7.0), 2% carnol estabilized O/A emulsions with the required HLB of the test system and 3% carnol estabilized both types of emulsions. PMID:1228835

  7. [Carnol as a stabilizer of the emulsion I system].

    PubMed

    De Almeida Cunha, B C; Dini, M E

    1975-01-01

    "Carnol" insaponificable fraction from "chalky" carnauba wax, was tested for its emulsified system estabilizing abilities. The required HLB of test system, made up of mineral oil, water, polyoxyethylene sorbitan trioleate and sorbitam monooleate, was 9.0. 1% of carnol (w/v) formed A/O emulsions (HLB less than or equal to 7.0), 2% carnol estabilized O/A emulsions with the required HLB of the test system and 3% carnol estabilized both types of emulsions.

  8. Development of Nuclear Emulsion for Fast Neutron Measurement

    NASA Astrophysics Data System (ADS)

    Machii, Shogo; Kuwabara, Kenichi; Morishima, Kunihiro

    Nuclear emulsion is high sensitive photographic film used for detection of three-dimensional trajectory of charged particles. Energy resolution of nuclear emulsion is 21% (12%) FWHM against neutron energy of 2.8 MeV (4.9 MeV). Nuclear emulsion has high gamma ray rejection power. For now, at least 2×104 gamma rays/cm2, no increase of as a background for neutron measurement when scan using automatic nuclear emulsion read out system HTS. This value suggests that it is applicable even under high gamma ray environment, such as nuclear fusion reactor.

  9. Field testing of asphalt-emulsion radon-barrier system

    SciTech Connect

    Hartley, J.N.; Freeman, H.D.; Baker, E.G.; Elmore, M.R.; Nelson, D.A.; Voss, C.F.; Koehmstedt, P.L.

    1981-09-01

    Three years of laboratory and field testing have demonstrated that asphalt emulsion seals are effective radon diffusion barriers. Both laboratory and field tests in 1979, 1980 and 1981 have shown that an asphalt emulsion seal can reduce radon fluxes by greater than 99.9%. The effective diffusion coefficient for the various asphalt emulsion admix seals averages about 10/sup -6/ cm/sup 2//s. The 1981 joint field test is a culmination of all the technology developed to date for asphalt emulsion radon barrier systems. Preliminary results of this field test and the results of the 1980 field test are presented. 18 figures, 6 tables.

  10. Hepatic uptake of lipid-soluble drugs from fat emulsion.

    PubMed

    Umezawa, K; Karino, A; Hayashi, M; Tahara, K; Kimura, A; Awazu, S

    1991-10-01

    Oil violet in a fat emulsion was taken up into the parenchymal cells of rat liver in vitro. The uptake was greater at 37 degrees C than 25 degrees C or 4 degrees C, and it was increased by addition of postheparin plasma including lipoprotein lipase activity into the reaction medium. The uptake from the emulsion with smaller particles was greater than that from the emulsion with larger particles. The hepatic uptake of 14C-cholesteryl oleate in the emulsion by recirculating perfusion of the liver in situ was also increased by postheparin plasma in the perfusion medium. Its enhancing effect was found for distribution in the parenchymal cells but not in the Kupffer cells. The previous perfusion of Intralipos of the commercial fat emulsion reduced the hepatic uptake of 14C-cholesteryl oleate in the emulsion. The emulsion particle sizes were reduced by postheparin plasma both in vitro and in situ. Consequently, it was suggested that a lipid-soluble compound entrapped in the fat emulsion is taken up into the parenchymal cells by receptor-mediated process via the reduced particle sizes emulsion (remnant), which is a mechanism similar to the dietary fat metabolism.

  11. Regio- and stereospecific living polymerization and copolymerization of (E)-1,3-pentadiene with 1,3-butadiene by half-sandwich scandium catalysts.

    PubMed

    Nishii, Kei; Kang, Xiaohui; Nishiura, Masayoshi; Luo, Yi; Hou, Zhaomin

    2013-07-01

    The living isospecific-cis-1,4-polymerization and block-copolymerization of (E)-1,3-pentadiene with 1,3-butadiene have been achieved for the first time by using cationic half-sandwich scandium catalysts.

  12. Crude oil emulsions containing a compatible fluorochemical surfactant

    SciTech Connect

    Karydas, A.; Rodgers, J.

    1991-02-19

    This patent describes a crude oil in water emulsion, which is stable to both breakdown and phase inversion up to at least about 50{degrees} C., the emulsion containing an effective, compatible, emulsion stabilizing amount of a fluorochemical surfactant of the formula (R{sub {ital f}}){sub {ital n}}A{sub {ital m}}Q wherein R{sub {ital f}} is an inert, stable, oleophobic and hydrophobic fluoroaliphatic group having up to about 20 carbon atoms; n is an integer from 1 to 3; A is a direct bond or an organic linking group and is covalently bonded to both R{sub {ital f}} and Q; Q is an anionic, nonionic or amphoteric group; and m is an integer from 1 to 3; wherein the amount of weight of the fluorochemical surfactant present in the emulsion being between about 0.001 and 1% by weight of the emulsion, in the presence of absence of up to about 2% by weight of a crude oil emulsion promoting hydrocarbon surfactant, with the proviso that at least about 0.005% by weight total fluorochemical and hydrocarbon surfactant is present, based upon the weight of emulsion, and wherein the emulsion contains bout 15 to about 90 percent by weight water, based upon the weight of emulsion, such that the viscosity of the emulsion is less than about 50% of the viscosity of the crude oil, and wherein the emulsion spontaneously breaks down into an aqueous and crude oil phase at a temperature between about 55{degrees} and 75{degrees} C.

  13. Tunable mechano-responsive organogels by ring-opening copolymerizations of N-carboxyanhydrides

    PubMed Central

    Fan, Jingwei; Zou, Jiong; He, Xun; Zhang, Fuwu; Zhang, Shiyi; Raymond, Jeffery E.; Wooley, Karen L.

    2013-01-01

    The simple copolymerization of N-carboxyanhydride (NCA) monomers is utilized to generate copolypeptides having a combination of α-helix and β-sheet sub-structures that, when grown from a solvophilic synthetic polymer block segment, are capable of driving mechano-responsive supramolecular sol-to-gel-to-sol and sol-to-gel-to-gel transitions reversibly, which allow also for injection-based processing and self-healing behaviors. A new type of polypeptide-based organogelator, methoxy poly(ethylene glycol)-block-poly(γ-benzyl-l-glutamate-co-glycine) (mPEG-b-P(BLG-co-Gly)), is facilely synthesized by statistical ring-opening copolymerizations (ROPs) of γ-benzyl-l-glutamate (BLG) and glycine (Gly) NCAs initiated by mPEG-amine. These systems exhibit tunable secondary structures and result in sonication stimulus responsiveness of the organogels with the polypeptide segment variation, controlled by varying the ratio of BLG NCA to Gly NCA during the copolymerizations. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) studies indicate the α-helical component decreases while the β-sheet content increases systematically with a higher mole fraction of Gly in the polypeptide segment. The supramolecular assembly of β-sheet nanofibrils, having a tunable width over the range of 10.4 – 14.5 nm with varied BLG to Gly ratio, are characterized by transmission electron microscopy (TEM). The further self-assembly of these nanostructures into 3-D gel networks within N,N-dimethylformamide (DMF) occurs at low critical gelation concentrations (CGC) (lowest ca. 0.6 wt %). Increased BLG to Gly ratios lead to an increase of the α-helical component in the secondary structures of the polypeptide segments, resulting in wider and more flexible nanofibrils. The presence of α-helical component in the polymers enhances the stability of the organogels against sonication, and instantaneous gel-to-gel transitions are observed as in situ reconstruction of networks

  14. Reactivity of vinyl ethers and vinyl ribosides in UV-initiated free radical copolymerization with acceptor monomers.

    PubMed

    Pichavant, Loic; Guillermain, Céline; Coqueret, Xavier

    2010-09-13

    The reactivity of various vinyl ethers and vinyloxy derivatives of ribose in the presence of diethyl fumarate or diethyl maleate was investigated for evaluating the potential of donor-acceptor-type copolymerization applied to unsaturated monomers derived from renewable feedstock. The photochemically induced polymerization of model monomer blends in the bulk state was monitored by infrared spectroscopy. The method allowed us to examine the influence of monomer pair structure on the kinetic profiles. The simultaneous consumption of both monomers was observed, supporting an alternating copolymerization mechanism. A lower reactivity of the blends containing maleates compared with fumarates was confirmed. The obtained kinetic data revealed a general correlation between the initial polymerization rate and the Hansen parameter δ(H) associated with the H-bonding aptitude of the donor monomer.

  15. Acceleration and selective monomer addition during aqueous RAFT copolymerization of ionic monomers at 25 °C.

    PubMed

    Li, Guangxiang; Xu, Na; Yu, Qiuping; Lu, Xinhua; Chen, Hong; Cai, Yuanli

    2014-08-01

    An acceleration effect and selective monomer addition during RAFT copolymerization of the oppositely-charged ionic monomers in dilute aqueous solution at 25 °C are reported. The reaction is conducted using a non-ionic water-soluble polymer as a macromolecular chain transfer agent under visible light irradiation. A fast iterative polymerization can be induced, even in dilute solution, by the favorable ionic interactions and in situ self-assembly of zwitterionic growing chains. Selelctive monomer addition is achieved in the statistical copolymerization due to the ion-pairing of the oppositely-charged monomers, such as precisely the same reaction rates at a 1:1 of monomer ratio, otherwise a faster reaction of the minor monomer component over the major one. These behaviors open up an avenue towards the rapid synthesis of sequence-controlled zwitterionic polyelectrolytes that can satisfy the demands of emerging biological applications. PMID:24889131

  16. Preparation of a DNA matrix via an electrochemically directed copolymerization of pyrrole and oligonucleotides bearing a pyrrole group.

    PubMed Central

    Livache, T; Roget, A; Dejean, E; Barthet, C; Bidan, G; Téoule, R

    1994-01-01

    A new methodology for the preparation of addressed DNA matrices is described. The process includes an electrochemically directed copolymerization of pyrrole and oligonucleotides bearing on their 5' end a pyrrole moiety introduced by phosphoramidite chemistry. The electro-controlled synthesis of the copolymer (poly-pyrrole) gives, in one step, a solid conducting film deposited on the surface of an electrode. The resulting polymer consists of pyrrole chains bearing covalently linked oligonucleotide. The polymer growth is limited to the electrode surface, so that it is possible to prepare a DNA matrix on a multiple electrode device by successive copolymerizations. A support bearing four oligonucleotides was used to detect three ras mutations on a synthetic DNA fragment. PMID:8065902

  17. CAMELOT: A machine learning approach for coarse-grained simulations of aggregation of block-copolymeric protein sequences

    SciTech Connect

    Ruff, Kiersten M.; Harmon, Tyler S.; Pappu, Rohit V.

    2015-12-28

    We report the development and deployment of a coarse-graining method that is well suited for computer simulations of aggregation and phase separation of protein sequences with block-copolymeric architectures. Our algorithm, named CAMELOT for Coarse-grained simulations Aided by MachinE Learning Optimization and Training, leverages information from converged all atom simulations that is used to determine a suitable resolution and parameterize the coarse-grained model. To parameterize a system-specific coarse-grained model, we use a combination of Boltzmann inversion, non-linear regression, and a Gaussian process Bayesian optimization approach. The accuracy of the coarse-grained model is demonstrated through direct comparisons to results from all atom simulations. We demonstrate the utility of our coarse-graining approach using the block-copolymeric sequence from the exon 1 encoded sequence of the huntingtin protein. This sequence comprises of 17 residues from the N-terminal end of huntingtin (N17) followed by a polyglutamine (polyQ) tract. Simulations based on the CAMELOT approach are used to show that the adsorption and unfolding of the wild type N17 and its sequence variants on the surface of polyQ tracts engender a patchy colloid like architecture that promotes the formation of linear aggregates. These results provide a plausible explanation for experimental observations, which show that N17 accelerates the formation of linear aggregates in block-copolymeric N17-polyQ sequences. The CAMELOT approach is versatile and is generalizable for simulating the aggregation and phase behavior of a range of block-copolymeric protein sequences.

  18. CAMELOT: A machine learning approach for coarse-grained simulations of aggregation of block-copolymeric protein sequences

    NASA Astrophysics Data System (ADS)

    Ruff, Kiersten M.; Harmon, Tyler S.; Pappu, Rohit V.

    2015-12-01

    We report the development and deployment of a coarse-graining method that is well suited for computer simulations of aggregation and phase separation of protein sequences with block-copolymeric architectures. Our algorithm, named CAMELOT for Coarse-grained simulations Aided by MachinE Learning Optimization and Training, leverages information from converged all atom simulations that is used to determine a suitable resolution and parameterize the coarse-grained model. To parameterize a system-specific coarse-grained model, we use a combination of Boltzmann inversion, non-linear regression, and a Gaussian process Bayesian optimization approach. The accuracy of the coarse-grained model is demonstrated through direct comparisons to results from all atom simulations. We demonstrate the utility of our coarse-graining approach using the block-copolymeric sequence from the exon 1 encoded sequence of the huntingtin protein. This sequence comprises of 17 residues from the N-terminal end of huntingtin (N17) followed by a polyglutamine (polyQ) tract. Simulations based on the CAMELOT approach are used to show that the adsorption and unfolding of the wild type N17 and its sequence variants on the surface of polyQ tracts engender a patchy colloid like architecture that promotes the formation of linear aggregates. These results provide a plausible explanation for experimental observations, which show that N17 accelerates the formation of linear aggregates in block-copolymeric N17-polyQ sequences. The CAMELOT approach is versatile and is generalizable for simulating the aggregation and phase behavior of a range of block-copolymeric protein sequences.

  19. Synthesis of copolymerized porous organic frameworks with high gas storage capabilities at both high and low pressures.

    PubMed

    Pei, Cuiying; Ben, Teng; Li, Yanqiang; Qiu, Shilun

    2014-06-11

    A series of copolymerized porous organic frameworks (C-POFs) were synthesized with monomers of tetrakis(4-bromophenyl)methane and tris(4-bromophenyl)amine in different ratios by a Yamamoto-type Ullmann cross-coupling reaction. These C-POFs exhibit high physicochemical stability, large surface areas and excellent H2, CH4 and CO2 adsorption properties both at low and high pressures.

  20. Perfluorochemical emulsions decrease Kupffer cell phagocytosis

    SciTech Connect

    Bottalico, L.A.; Betensky, H.T.; Min, Y.B.; Weinstock, S.B. )

    1991-07-01

    One drawback to using perfluorochemical emulsions as blood substitutes is that perfluorochemical particles are cleared from the blood by the reticuloendothelial system, primarily liver and spleen. The authors measured the impact of two perfluorochemical emulsions on clearance of colloidal carbon (less than 1 microns) and 51Cr-sheep red blood cells (about 8 microns) by the reticuloendothelial system in vivo and in the isolated perfused liver. Male rats were injected with 2 ml/100 gm body wt of Fluosol-DA or Oxypherol-ET for 4 consecutive days. Carbon (1 ml/100 gm body wt) or sheep red blood cells (0.05 ml of 5% vol/vol/100 gm body wt) were then injected intravenously (in vivo) or added to perfusate. Samples were taken at several time points for 1 hr. In the isolated perfused liver, carbon clearance was depressed by 25% 1 day after treatment. Rates returned to control levels by 12 days in Fluosol-DA-treated rats but remained depressed by 67% in Oxypherol-ET-treated rats. Sheep red blood cell (8 microns) clearance was two to five times slower than carbon clearance and depressed by 40% in livers from Fluosol-DA rats 1 day and 12 days after treatment. Added serum did not improve phagocytosis. In vivo carbon clearance remained normal in Fluosol-DA-treated rats but decreased by 74% in Oxypherol-ET-treated rats 1 day after treatment, returning to normal by 12 days. Clearance rates were similar in control rats in vivo and in the perfused liver. They conclude that the isolated perfused liver is a good model to measure liver clearance function. Although low doses of perfluorochemical emulsions may depress Kupffer cell phagocytosis, general reticuloendothelial system function is not significantly compromised.

  1. Swelling and drug release behavior of poly(2-hydroxyethyl methacrylate/itaconic acid) copolymeric hydrogels obtained by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Tomić, S. Lj.; Mićić, M. M.; Filipović, J. M.; Suljovrujić, E. H.

    2007-05-01

    The new copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were prepared by gamma irradiation, in order to examine the potential use of these hydrogels in controlled drug release systems. The influence of IA content in the gel on the swelling characteristics and the releasing behavior of hydrogels, and the effect of different drugs, theophylline (TPH) and fenethylline hydrochloride (FE), on the releasing behavior of P(HEMA/IA) matrix were investigated in vitro. The diffusion exponents for swelling and drug release indicate that the mechanisms of buffer uptake and drug release are governed by Fickian diffusion. The swelling kinetics and, therefore, the release rate depends on the matrix swelling degree. The drug release was faster for copolymeric hydrogels with a higher content of itaconic acid. Furthermore, the drug release for TPH as model drug was faster due to a smaller molecular size and a weaker interaction of the TPH molecules with(in) the P(HEMA/IA) copolymeric networks.

  2. Linear oil displacement by the emulsion entrapment process. [Dissertation

    SciTech Connect

    Schmidt, D.P.

    1982-01-01

    Lack of mobility control is one of the major impediments to successful enhanced oil recovery, especially for high viscosity oils. This work presents experimental and theoretical results for linear secondary oil displacements using dilute, stable suspensions of oil drops. The major hypothesis is that emulsions provide mobility control through entrapment or local permeability reduction, not through viscosity ratio improvement. In order to describe the displacement process, previous emulsion filtration theory is extended to longer cores and to two-phase flow. Quantitative agreement between theory and experiment is satisfactory for continuous secondary oil displacement with various drop-size emulsions in unconsolidated sand packs of permeabilities ranging from 0.7 ..mu..m/sup 2/ to 3.3 ..mu..m/sup 2/. Linear emulsion floods are shown to be most effective when the mean drop-size to pore-size ratio is in the region between straining and interception at the emulsion shock. Floods are more effective when the emulsion concentration is high which minimizes retention lag. Additionally, a parallel flooding apparatus is utilized to determine qualitatively the macroscopic benefits of emulsion mobility control. Direct analogies are established between augmented oil recovery with dilute emulsions and with entrapping polymers.

  3. Maximizing the stability of pyrolysis oil/diesel fuel emulsions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Several emulsions consisting of biomass pyrolysis oil (bio-oil) in diesel fuel were produced and analyzed for stability over time. An ultrasonic probe was used to generate microscopic droplets of bio-oil suspended in diesel fuel, and this emulsion was stabilized using surfactant chemicals. The most...

  4. Water-in-diesel emulsions and related systems.

    PubMed

    Lif, Anna; Holmberg, Krister

    2006-11-16

    Water-in-diesel emulsions are fuels for regular diesel engines. The advantages of an emulsion fuel are reductions in the emissions of nitrogen oxides and particulate matters, which are both health hazardous, and reduction in fuel consumption due to better burning efficiency. An important aspect is that diesel emulsions can be used without engine modifications. This review presents the influence of water on the emissions and on the combustion efficiency. Whereas there is a decrease in emissions of nitrogen oxides and particulate matters, there is an increase in the emissions of hydrocarbons and carbon monoxide with increasing water content of the emulsion. The combustion efficiency is improved when water is emulsified with diesel. This is a consequence of the microexplosions, which facilitate atomization of the fuel. The review also covers related fuels, such as diesel-in-water-in-diesel emulsions, i.e., double emulsions, water-in-diesel microemulsions, and water-in-vegetable oil emulsions, i.e., biodiesel emulsions. A brief overview of other types of alternative fuels is also included.

  5. Zero-Valent Metal Emulsion for Reductive Dehalogenation of DNAPLs

    NASA Technical Reports Server (NTRS)

    Reinhart, Debra R. (Inventor); Clausen, Christian (Inventor); Gelger, Cherie L. (Inventor); Quinn, Jacqueline (Inventor); Brooks, Kathleen (Inventor)

    2006-01-01

    A zero-valent metal emulsion is used to dehalogenate solvents, such as pooled dense non-aqueous phase liquids (DNAPLs), including trichloroethylene (TCE). The zero-valent metal emulsion contains zero-valent metal particles, a surfactant, oil and water, The preferred zero-valent metal particles are nanoscale and microscale zero-valent iron particles.

  6. Nanoscale and Microscale Iron Emulsions for Treating DNAPL

    NASA Technical Reports Server (NTRS)

    Geiger, Cherie L.

    2002-01-01

    This study demonstrated the feasibility of using emulsified nanoscale and microscale iron particles to enhance dehalogenation of (Dense Non-Aqueous Phase Liquid) DNAPL free-phase. The emulsified system consisted of a surfactant-stabilized, biodegradable oil-in-water emulsion with nanoscale or microscale iron particles contained within the emulsion droplets. It was demonstrated that DNAPLs, such as trichloroethene (TCE), diffuse through the oil membrane of the emulsion particle whereupon they reach an aqueous interior and the surface of an iron particle where dehalogenation takes place. The hydrocarbon reaction by-products of the dehalogenation reaction, primarily ethene (no chlorinated products detected), diffuse out of the emulsion droplet. This study also demonstrated that an iron-emulsion system could be delivered in-situ to the DNAPL pool in a soil matrix by using a simulated push well technique. Iron emulsions degraded pure TCE at a rate comparable to the degradation of dissolved phase TCE by iron particles, while pure iron had a very low degradation rate for free-phase TCE. The iron-emulsion systems can be injected into a sand matrix where they become immobilized and are not moved by flowing water. It has been documented that surfactant micelles possess the ability to pull pooled TCE into emulsion droplets where degradation of TCE takes place.

  7. Mannans as stabilizers of oil-in-water beverage emulsions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant polysaccharides and gums such as gum arabic (GA) are commonly used as stabilizers of oil-in-water emulsions. O-acetyl-galactoglucomannan (GGM), a by-product from mechanical pulping of spruce wood, is able to stabilize colloidal wood resin emulsions (Hannuksela and Holmbom, 2004), but its use a...

  8. Rheological properties of heavy oils and heavy oil emulsions

    SciTech Connect

    Khan, M.R.

    1996-06-01

    In this study, the author investigated the effects of a number of process variables such as shear rate, measurement temperature, pressure, the influence of pretreatment, and the role of various amounts of added water on the rheology of the resulting heavy oil or the emulsion. Rheological properties of heavy oils and the corresponding emulsions are important from transportation and processing standpoints.

  9. 21 CFR 524.802 - Enrofloxacin, silver sulfadiazine emulsion.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Enrofloxacin, silver sulfadiazine emulsion. 524... ANIMAL DRUGS § 524.802 Enrofloxacin, silver sulfadiazine emulsion. (a) Specifications. Each milliliter contains 5 milligrams (mg) enrofloxacin and 10 mg silver sulfadiazine. (b) Sponsor. See No. 000859 in §...

  10. 21 CFR 524.802 - Enrofloxacin, silver sulfadiazine emulsion.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Enrofloxacin, silver sulfadiazine emulsion. 524... ANIMAL DRUGS § 524.802 Enrofloxacin, silver sulfadiazine emulsion. (a) Specifications. Each milliliter contains 5 milligrams (mg) enrofloxacin and 10 mg silver sulfadiazine. (b) Sponsor. See No. 000859 in §...

  11. Zero-Valent Metal Emulsion for Reductive Dehalogenation of DNAPLS

    NASA Technical Reports Server (NTRS)

    Reinhart, Debra R. (Inventor); Clausen, Christian (Inventor); Geiger, Cherie L. (Inventor); Quinn, Jacqueline (Inventor); Brooks, Kathleen (Inventor)

    2003-01-01

    A zero-valent metal emulsion is used to dehalogenate solvents, such as pooled dense non-aqueous phase liquids (DNAPLs), including trichloroethylene (TCE). The zero-valent metal emulsion contains zero-valent metal particles, a surfactant, oil and water. The preferred zero-valent metal particles are nanoscale and microscale zero-valent iron particles

  12. Synthesis of metallic nanoshells on porphyrin-stabilized emulsions

    DOEpatents

    Wang, Haorong; Song, Yujiang; Shelnutt, John A.; Medforth, Craig J.

    2011-12-13

    Metal nanostructures formed by photocatalytic interfacial synthesis using a porphyrin-stabilized emulsion template and the method for making the nanostructures. Catalyst-seeded emulsion droplets are employed as templates for hollow-nanoshell growth. The hollow metal nanospheres may be formed with or without inclusions of other materials.

  13. Development of an Acoustic Droplet Vaporization, Ultrasound Drug Delivery Emulsion

    NASA Astrophysics Data System (ADS)

    Fabiilli, Mario L.; Sebastian, Ian E.; Fowlkes, J. Brian

    2010-03-01

    Many therapeutic applications of ultrasound (US) include the use of pefluorocarbon (PFC) microbubbles or emulsions. These colloidal systems can be activated in the presence of US, which in the case of emulsions, results in the production of bubbles—a process known as acoustic droplet vaporization (ADV). ADV can be used as a drug delivery mechanism, thereby yielding the localized release of toxic agents such a chemotherapeutics. In this work, emulsions that contain PFC and chlorambucil, a chemotherapy drug, are formulated using albumin or lipid shells. For albumin droplets, the oil phase—which contained CHL—clearly enveloped the PFC phase. The albumin emulsion also displayed better retention of CHL in the absence of US, which was evaluated by incubating Chinese hamster ovary cells with the various formulations. Thus, the developed emulsions are suitable for further testing in ADV-induced release of CHL.

  14. Rejuvenation of Spent Media via Supported Emulsion Liquid Membranes

    NASA Technical Reports Server (NTRS)

    Wiencek, John M.

    2002-01-01

    The overall goal of this project was to maximize the reuseability of spent fermentation media. Supported emulsion liquid membrane separation, a highly efficient extraction technique, was used to remove inhibitory byproducts during fermentation; thus, improve the yield while reducing the need for fresh water. The key objectives of this study were: (1) Develop an emulsion liquid membrane system targeting low molecular weight organic acids which has minimal toxicity on a variety of microbial systems. (2) Conduct mass transfer studies to allow proper modeling and design of a supported emulsion liquid membrane system. (3) Investigate the effect of gravity on emulsion coalescence within the membrane unit. (4) Access the effect of water re-use on fermentation yields in a model microbial system. and (5) Develop a perfusion-type fermentor utilizing a supported emulsion liquid membrane system to control inhibitory fermentation byproducts (not completed due to lack of funds)

  15. Chitin nanocrystals for Pickering high internal phase emulsions.

    PubMed

    Perrin, Emilie; Bizot, Hervé; Cathala, Bernard; Capron, Isabelle

    2014-10-13

    Chitin is a natural polymer of glucosamine bearing N-acetyl groups. Chitin nanocrystals (ChiNCs), resulting from the acid hydrolysis of amorphous regions of chitin, are crystalline positively charged rod-like particles. ChiNCs show some interfacial properties and very efficiently stabilize oil/water interfaces, leading to the so-called Pickering emulsions. In accordance with the irreversible adsorption of particles, these Pickering emulsions proved stable over time, with constant emulsion volume for several months, even though natural creaming may occur. The emulsions produced are not clearly susceptible to ionic strength or pH in terms of average droplet diameter. However, when mixed with a large amount of oil, high internal phase emulsions (HIPE) containing up to 96% of internal phase are formed as a gel with a texture that can be modulated from soft to solid gel by adjusting concentration, pH, and ionic strength.

  16. Pickering emulsions for food applications: background, trends, and challenges.

    PubMed

    Berton-Carabin, Claire C; Schroën, Karin

    2015-01-01

    Particle-stabilized emulsions, also referred to as Pickering emulsions, have garnered exponentially increasing interest in recent years. This has also led to the first food applications, although the number of related publications is still rather low. The involved stabilization mechanisms are fundamentally different as compared to conventional emulsifiers, which can be an asset in terms of emulsion stability. Even though most of the research on Pickering emulsions has been conducted on model systems, with inorganic solid particles, recent progress has been made on the utilization of food-grade or food-compatible organic particles for this purpose. This review reports the latest advances in that respect, including technical challenges, and discusses the potential benefits and drawbacks of using Pickering emulsions for food applications, as an alternative to conventional emulsifier-based systems.

  17. Domain and droplet sizes in emulsions stabilized by colloidal particles

    NASA Astrophysics Data System (ADS)

    Frijters, Stefan; Günther, Florian; Harting, Jens

    2014-10-01

    Particle-stabilized emulsions are commonly used in various industrial applications. These emulsions can present in different forms, such as Pickering emulsions or bijels, which can be distinguished by their different topologies and rheology. We numerically investigate the effect of the volume fraction and the uniform wettability of the stabilizing spherical particles in mixtures of two fluids. For this, we use the well-established three-dimensional lattice Boltzmann method, extended to allow for the added colloidal particles with non-neutral wetting properties. We obtain data on the domain sizes in the emulsions by using both structure functions and the Hoshen-Kopelman (HK) algorithm, and we demonstrate that both methods have their own (dis)advantages. We confirm an inverse dependence between the concentration of particles and the average radius of the stabilized droplets. Furthermore, we demonstrate the effect of particles detaching from interfaces on the emulsion properties and domain-size measurements.

  18. An exclusively based parenteral fish-oil emulsion reverses cholestasis.

    PubMed

    Triana Junco, Miryam; García Vázquez, Natalia; Zozaya, Carlos; Ybarra Zabala, Marta; Abrams, Steven; García de Lorenzo, Abelardo; Sáenz de Pipaón Marcos, Miguel

    2014-10-25

    Prolonged parenteral nutrition (PN) leads to liver damage. Recent interest has focused on the lipid component of PN. A lipid emulsion based on w-3 fatty acids decrease conjugated bilirubin. A mixed lipid emulsion derived from soybean, coconut, olive, and fish oils reverses jaundice. Here we report the reversal of cholestasis and the improvement of enteral feeding tolerance in 1 infant with intestinal failure-associated liver disease. Treatment involved the substitution of a mixed lipid emulsion with one containing primarily omega-3 fatty acids during 37 days. Growth and biochemical tests of liver function improved significantly. This suggests that fat emulsions made from fish oils may be more effective means of treating this condition compared with an intravenous lipid emulsion containing soybean oil, medium -chain triglycerides, olive oil, and fish oil.

  19. Chemically induced graft copolymerization of 2-hydroxyethyl methacrylate onto polyurethane surface for improving blood compatibility

    NASA Astrophysics Data System (ADS)

    He, Chunli; Wang, Miao; Cai, Xianmei; Huang, Xiaobo; Li, Li; Zhu, Haomiao; Shen, Jian; Yuan, Jiang

    2011-11-01

    To improve hydrophilicity and blood compatibility properties of polyurethane (PU) film, we chemically induced graft copolymerization of 2-hydroxyethyl methacrylate (HEMA) onto the surface of polyurethane film using benzoyl peroxide as an initiator. The effects of grafting temperature, grafting time, monomer and initiator concentrations on the grafting yields were studied. The maximum grafting yield value was obtained 0.0275 g/cm2 for HEMA. Characterization of the films was carried out by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), water contact angle measurements. ATR-FTIR data showed that HEMA was successfully grafted onto the PU films surface. Water contact angle measurement demonstrated the grafted films possessed a relatively hydrophilic surface. The blood compatibility of the grafted films was preliminarily evaluated by a platelet-rich plasma adhesion test and hemolysis test. The results of platelet adhesion experiment showed that polyurethane grafted polymerization with monomer of 2-hydroxyethyl methacrylate had good blood compatibility featured by the low platelet adhesion. Hemolysis rate of the PU-g-PHEMA films was dramatically decreased than the ungrafted PU films. This kind of new biomaterials grafted with HEMA monomers might have a potential usage for biomedical applications.

  20. Recent Development of Copolymeric Delivery System for Anticancer Agents Based on Cyclodextrin Derivatives.

    PubMed

    Feng, Runliang; Deng, Peizong; Teng, Fangfang; Song, Zhimei

    2016-01-01

    Core-shell structured aggregates of amphiphilic block copolymer are hopefully drug delivery system because of their ability to encapsulate hydrophobic drugs, and their hydrophilic shell can prolong retention time of drugs in the blood circulation system. Cyclodextrin is a kind of hydrophilic polysaccharide containing multiple hydroxyl groups, providing an inner hole that can load small molecule through host-guest interaction. These hydroxyl groups or their derived functional ones are utilized in conjugation with polymeric chains to form block copolymers. These copolymers can not only encapsulate hydrophobic drugs, but also encapsulate hydrophilic drugs (like DNA, protein, etc) through hydrophobic, host-guest or electrostatic interactions, which strengthen interaction between drugs and materials compared with general copolymers, indicating that formed drug delivery systems are more stable. By introduction of target molecule, they also achieve selective delivery of drugs to specific tissues or organs. So, several researchers are stimulated to carry out many studies for the development of cyclodextrin copolymeric drug delivery systems in recent. In this review, we focus the cyclodextrin copolymers' application in the anticancer agents' delivery. PMID:26349814

  1. Dinuclear Zinc Salen Catalysts for the Ring Opening Copolymerization of Epoxides and Carbon Dioxide or Anhydrides.

    PubMed

    Thevenon, Arnaud; Garden, Jennifer A; White, Andrew J P; Williams, Charlotte K

    2015-12-21

    A series of four dizinc complexes coordinated by salen or salan ligands, derived from ortho-vanillin and bearing (±)-trans-1,2-diaminocyclohexane (L1) or 2,2-dimethyl-1,3-propanediamine (L2) backbones, is reported. The complexes are characterized using a combination of X-ray crystallography, multinuclear NMR, DOSY, and MALDI-TOF spectroscopies, and elemental analysis. The stability of the dinuclear complexes depends on the ligand structure, with the most stable complexes having imine substituents. The complexes are tested as catalysts for the ring-opening copolymerization (ROCOP) of CO2/cyclohexene oxide (CHO) and phthalic anhydride (PA)/CHO. All complexes are active, and the structure/activity relationships reveal that the complex having both L2 and imine substituents displays the highest activity. In the ROCOP of CO2/CHO its activity is equivalent to other metal salen catalysts (TOF = 44 h(-1) at a catalyst loading of 0.1 mol %, 30 bar of CO2, and 80 °C), while for the ROCOP of PA/CHO, its activity is slightly higher than other metal salen catalysts (TOF = 198 h(-1) at a catalyst loading of 1 mol % and 100 °C). Poly(ester-block-carbonate) polymers are also afforded using the most active catalyst by the one-pot terpolymerization of PA/CHO/CO2. PMID:26605983

  2. Droplet migration in emulsion systems measured using MR methods.

    PubMed

    Hollingsworth, K G; Johns, M L

    2006-04-15

    The migration of emulsion droplets under shear flow remains a largely unexplored area of study, despite the existence of an extensive literature on the analogous problem of solid particle migration. A novel methodology is presented to track the shear-induced migration of emulsion droplets based on magnetic resonance imaging (MRI). The work is in three parts: first, single droplets of one Newtonian fluid are suspended in a second Newtonian fluid (water in silicone oil (PDMS)) and are tracked as they migrate within a Couette cell; second, the migration of emulsion droplets in Poiseuille flow is considered; third, water-in-silicone oil emulsions are sheared in a Couette cell. The effect of (a) rotational speed of the Couette, (b) the continuous phase viscosity, and (c) the droplet phase concentration are considered. The equilibrium extent of migration and rate of migration increase with rotational speed for two different emulsion systems and increased continuous phase viscosity, leads to a greater equilibrium extent of migration. The relationship between the droplet phase concentration and migration is however complex. These results for semi-concentrated emulsion systems and wide-gap Couette cells are not well described by existing models of emulsion droplet migration. PMID:16257005

  3. Remediation of groundwater contaminated with DNAPLs by biodegradable oil emulsion.

    PubMed

    Lee, Young-Chul; Kwon, Tae-Soon; Yang, Jung-Seok; Yang, Ji-Won

    2007-02-01

    Emulsion-based remediation with biodegradable vegetable oils was investigated as an alternative technology for the treatment of subsurface DNAPLs (dense non-aqueous phase liquids) such as TCE (trichloroethylene) and PCE (perchloroethylene). Corn and olive oil emulsions obtained by homogenization at 8000rpm for 15min were used. The emulsion droplets prepared with corn and olive oil gave a similar size distribution (1-10microm) and almost all of initially injected oil, >90%, remained in a dispersed state. In batch experiments, 2% (v/v) oil emulsion could adsorb up to 11,000ppm of TCE or 18,000ppm of PCE without creating a free phase. Results of one-dimensional column flushing studies indicated that contaminants with high aqueous solubility could be efficiently removed by flushing with vegetable oil emulsions. Removal efficiencies exceeded 98% for TCE and PCE with both corn and olive oil emulsions. The results of this study show that flushing with biodegradable oil emulsion can be used for the remediation of groundwater contaminated by DNAPLs.

  4. Factors that affect Pickering emulsions stabilized by graphene oxide.

    PubMed

    He, Yongqiang; Wu, Fei; Sun, Xiying; Li, Ruqiang; Guo, Yongqin; Li, Chuanbao; Zhang, Lu; Xing, Fubao; Wang, Wei; Gao, Jianping

    2013-06-12

    Stable Pickering emulsions were prepared using only graphene oxide (GO) as a stabilizer, and the effects of the type of oil, the sonication time, the GO concentration, the oil/water ratio, and the pH value on the stability, type, and morphology of these emulsions were investigated. In addition, the effects of salt and the extent of GO reduction on emulsion formation and stability were studied and discussed. The average droplet size decreased with sonication time and with GO concentration, and the emulsions tended to achieve good stability at intermediate oil/water ratios and at low pH values. In all solvents, the emulsions were of the oil-in-water type, but interestingly, some water-in-oil-in-water (w/o/w) multiple emulsion droplets were also observed with low GO concentrations, low pH values, high oil/water ratios, high salt concentrations, or moderately reduced GO in the benzyl chloride-water system. A Pickering emulsion stabilized by Ag/GO was also prepared, and its catalytic performance for the reduction of 4-nitrophenol was investigated. This research paves the way for the fabrication of graphene-based functional materials with novel nanostructures and microstructures.

  5. Oil-in-oil emulsions stabilised solely by solid particles.

    PubMed

    Binks, Bernard P; Tyowua, Andrew T

    2016-01-21

    A brief review of the stabilisation of emulsions of two immiscible oils is given. We then describe the use of fumed silica particles coated with either hydrocarbon or fluorocarbon groups in acting as sole stabilisers of emulsions of various vegetable oils with linear silicone oils (PDMS) of different viscosity. Transitional phase inversion of emulsions, containing equal volumes of the two oils, from silicone-in-vegetable (S/V) to vegetable-in-silicone (V/S) occurs upon increasing the hydrophobicity of the particles. Close to inversion, emulsions are stable to coalescence and gravity-induced separation for at least one year. Increasing the viscosity of the silicone oil enables stable S/V emulsions to be prepared even with relatively hydrophilic particles. Predictions of emulsion type from calculated contact angles of a silica particle at the oil-oil interface are in agreement with experiment provided a small polar contribution to the surface energy of the oils is included. We also show that stable multiple emulsions of V/S/V can be prepared in a two-step procedure using two particle types of different hydrophobicity. At fixed particle concentration, catastrophic phase inversion of emulsions from V/S to S/V can be effected by increasing the volume fraction of vegetable oil. Finally, in the case of sunflower oil + 20 cS PDMS, the study is extended to particles other than silica which differ in chemical type, particle size and particle shape. Consistent with the above findings, we find that only sufficiently hydrophobic particles (clay, zinc oxide, silicone, calcium carbonate) can act as efficient V/S emulsion stabilisers.

  6. High internal phase emulsion with double emulsion morphology and their templated porous polymer systems.

    PubMed

    Lei, Lei; Zhang, Qi; Shi, Shuxian; Zhu, Shiping

    2016-12-01

    This paper reports synthesis of the first high internal phase emulsion (HIPE) system with double emulsion (DE) morphology (HIPE-DE). HIPE is a highly concentrated but highly stable emulsion system, which has a dispersed/internal phase fraction over 74vol%. DE represents an emulsion system that hierarchically encapsulates two immiscible phases. The combination of HIPE and DE provides an efficient method for fabrication of complex structures. In this work, HIPE-DE having a water-in-oil-in-water (W/O/W) morphology has been prepared for the first time via a simple one-step emulsification method with poly(2-(diethylamino)ethyl methacrylate) (PDEA) microgel particles as Pickering stabilizer. An oil phase fraction up to 90vol% was achieved by optimizing the microgel concentration in aqueous phase. The mechanism of the DE formation has been elucidated. It was found that while PDEA microgels stabilized the oil droplets in water, small amount protonated DEA monomers acted as surfactant and formed water-containing micelles inside the oil droplets. It was demonstrated that the W/O/W HIPE-DE could be precisely converted into porous polymer structures. With styrene as the oil phase in W/O/W HIPE-DE, porous polystyrene particles were obtained upon polymerization. With dissolved acrylamide as the aqueous phase and toluene as the continuous phase, porous polyacrylamide matrixes were prepared. Elevating temperature required for polymerization did not change the W/O/W HIPE-DE morphologies. This simple approach provides a versatile platform for synthesis of a variety of porous polymer systems. PMID:27560496

  7. Temperature dependence of emulsion morphologies and the dispersion morphology diagram. 2. Three-phase emulsions

    SciTech Connect

    Smith, D.H.; Johnson, G.K.

    1995-07-06

    Using several different compositions of the (pseudo)ternary amphiphile/oil/`water` system C{sub 6}H{sub 13}(OC{sub 2}H{sub 4}){sub 2}-OH/n-tetradecane/aqueous 10 mM NaCl, we show by means of electrical conductivity measurements that the temperature dependencies of the emulsion morphologies were consistent with predictions from isothermal dispersion morphology diagrams, thus contradicting phase inversion temperature ideas. 26 refs., 8 figs.

  8. Solid phase graft copolymerization of acrylic monomers onto thermoplastics and their use as blend compatibilizers

    NASA Astrophysics Data System (ADS)

    Subramanian, Srinivas

    This research work is an extension of some of the earlier work done on the development of solid phase grafting technique to graft various monomers onto polymers as well as postulation of the usefulness of the graft copolymers thus synthesized. Polystyrene grafted with acrylic acid, previously developed in bench scale, was synthesized in pilot-plant scale batches. Process parameter studies on the grafting of acrylic acid onto polypropylene and developmental studies on the grafting of maleic anhydride onto polystyrene were also done. Polymers grafted with polar molecules such as maleic anhydride and acrylic acid have been used to compatibilize immiscible blends of polar and non-polar polymers. On the same note, the applicability of the solid phase graft copolymers as blend compatibilizers were investigated and their performance was compared to commercially available compatibilizers. Solid phase graft copolymerization process is a technique to synthesize graft copolymers. Some of its salient features are use of minimal solvent to conduct the reaction and easy equipment modification. It is a low pressure and low temperature process. This technique provides a viable alternative to the environmentally hazardous, and time consuming conventional process currently in use. Hence, development of this technique could be beneficial not only to the plastics industry, but also to mankind. Also, this technique provides a low-cost and extremely easy method to develop graft copolymers such as acrylic acid functionalized polymers that are rapidly gaining popularity as blend compatibilizers and polymer reinforcing agents. A study that proves the potential of these solid phase graft copolymers as good blend compatibilizers for industrially important immiscible polymers will develop interest in the industries about this grafting process. The free radical solid phase graft copolymerization process was carried in a modified Brabender-type mixer fitted with specially designed blades to

  9. Temperature dependence of emulsion morphologies and the dispersion morphology diagram for three-phase emulsions

    SciTech Connect

    Smith, D.H.; Johnson, G.K.

    1995-12-31

    Using several different compositions of the (pseudo)ternary amphiphile/oil/{open_quotes}water{close_quotes} system C{sub 6}H{sub 13}(OC{sub 2}H{sub 4}){sub 2}OH/n-tetradecane/aqueous 10 mM NaCl that form oil-rich top phases (J), water-rich bottom phases ({Beta}), and middle-phase microemulsions (m), we showed by means of electrical conductivity measurements that the temperature dependencies of the three-phase emulsion morphologies were consistent with predictions from isothermal dispersion morphology diagrams, thus contradicting ideas derived from the PIT (phase inversion temperature) model for two-phase emulsions. In particular, we formed three-phase emulsions in which either (1) the continuous phase was an oil-rich phase (actually, m) below the PIT and the water-rich phase ({Beta}) above that temperature; (2) the water-rich phase was continuous both below and above the PIT; or (3) oil-rich phase was the continuous phase both below and above the PIT.

  10. Transport and Retention of Emulsion Droplets in Sandy Porous Media

    NASA Astrophysics Data System (ADS)

    Esahani, S. G.; Muller, K.; Chapra, S. C.; Ramsburg, A.

    2014-12-01

    Emulsions are commonly used as amendments during remediation; yet, the processes controlling the distribution of droplets within the subsurface are not well understood. Given that inadequate spatial and/or temporal delivery of amendments often leads to ineffective treatment, there is a need to better understand emulsion transport. Experiments were conducted to evaluate the transport and retention of emulsion droplets in columns containing Ottawa sands. Breakthrough curves and deposition profiles from these experiments were interrogated using a mathematical model capable of describing attachment, detachment, and straining to begin to elucidate the physical processes controlling delivery. Emulsions were constructed by stabilizing soybean oil droplets within a continuous aqueous phase. Physical properties of the resulting oil-in-water emulsions were favorable for subsurface delivery (nominal properties: 1 g/mL density; 10 cP viscosity; and 1.5 μm droplet d50). Emulsions were introduced to the columns for approximately two pore volumes and followed by an extended flush of background solution. Effluent droplet size distributions did not vary significantly over the course of the experiment and remained similar to those measured for the influent emulsion. Emulsion breakthrough curves exhibited tailing, and deposition profiles were found to be hyper-exponential and unaffected by extended periods of background flow. Depending on emulsion composition and flow characteristics, 10-30% of the injected emulsion was retained on the sand suggesting a non-negligible influence on accessible porosity over the course of the experiment. Experimental results were further interpreted using a droplet transport model that accounts for temporal and spatial variation in porosity due to the retention of the emulsion droplets. At present the model assumes a uniform size distribution of inelastic emulsion droplets which are transported by advection and dispersion, and exchanged with the solid

  11. Powdery Emulsion Explosive: A New Excellent Industrial Explosive

    NASA Astrophysics Data System (ADS)

    Ni, Ouqi; Zhang, Kaiming; Yu, Zhengquan; Tang, Shujuan

    2012-07-01

    Powdery emulsion explosive (PEE), a new powdery industrial explosive with perfect properties, has been made using an emulsification-spray drying technique. PEE is composed of 91-92.5 wt% ammonium nitrate (AN), 4.5-6 wt% organic fuels, and 1.5-1.8 wt% water. Due to its microstructure as a water-in-oil (W/O) emulsion and low water content, it has excellent detonation performance, outstanding water resistance, reliable safety, and good application compared with other industrial explosives, such as ammonite, emulsion explosives, and ANFO.

  12. Data on the physical characterization of oil in water emulsions.

    PubMed

    Zalazar, Aldana L; Gliemmo, María F; Campos, Carmen A

    2016-12-01

    This article contains experimental data and images for the physical characterization of oil in water emulsions. Mentioned data are related to the research article "Effect of stabilizers, oil level and structure on the growth of Zygosaccharomyces bailii and on physical stability of model systems simulating acid sauces" (A.L. Zalazar, M.F. Gliemmo, C.A. Campos, 2016) [1]. Physical characterization of emulsions was performed through the evaluation of Span and Specific Surface Area (SSA) determined by light scattering using a Mastersizer. Furthermore, microscopy images were recorded by confocal scanning laser microscopy (CSLM). The latter are presented to collaborate in the analysis of emulsion microstructure.

  13. Automated method of tracing proton tracks in nuclear emulsions

    NASA Astrophysics Data System (ADS)

    Ruan, Jin-lu; Li, Hong-yun; Song, Ji-wen; Zhang, Jian-fu; Chen, Liang; Zhang, Zhong-bing; Liu, Jin-liang; Liu, Lin-yue

    2015-07-01

    The low performance of the manual recognition of proton-recoil tracks in nuclear emulsions has limited its application to energy spectrum measurement of a pulsed neutron source. We developed an automated microscope system to trace proton-recoil tracks in nuclear emulsions. Given a start point on the proton track of interest, the microscope system can automatically trace and record the entire track using an image processing algorithm. Tests indicate that no interaction of the operator is needed in tracing the entire track. This automated microscope greatly reduces the labor of the operator and increases the efficiency of track data collection in nuclear emulsion.

  14. Data on the physical characterization of oil in water emulsions.

    PubMed

    Zalazar, Aldana L; Gliemmo, María F; Campos, Carmen A

    2016-12-01

    This article contains experimental data and images for the physical characterization of oil in water emulsions. Mentioned data are related to the research article "Effect of stabilizers, oil level and structure on the growth of Zygosaccharomyces bailii and on physical stability of model systems simulating acid sauces" (A.L. Zalazar, M.F. Gliemmo, C.A. Campos, 2016) [1]. Physical characterization of emulsions was performed through the evaluation of Span and Specific Surface Area (SSA) determined by light scattering using a Mastersizer. Furthermore, microscopy images were recorded by confocal scanning laser microscopy (CSLM). The latter are presented to collaborate in the analysis of emulsion microstructure. PMID:27631021

  15. Clickable degradable aliphatic polyesters via copolymerization with alkyne epoxy esters: synthesis and postfunctionalization with organic dyes.

    PubMed

    Teske, Nele S; Voigt, Julia; Shastri, V Prasad

    2014-07-23

    Degradable aliphatic polyesters are the cornerstones of nanoparticle (NP)-based therapeutics. In this paradigm, covalent modification of the NP with cell-targeting motifs and dyes can aid in guiding the NP to its destination and gaining visual confirmation. Therefore, strategies to impart chemistries along the polymer backbone that are amenable to easy modification, such as 1,3-dipolar cycloaddition of an azide to an alkyne (the "click reaction"), could be significant. Here we present a simple and efficient way to introduce alkyne groups at high density in aliphatic polyesters without compromising their crystallinity via the copolymerization of cyclic lactones with propargyl 3-methylpentenoate oxide (PMPO). Copolymers of lactic acid and ε-caprolactone with PMPO were synthesized with up to 9 mol % alkyne content, and accessibility of the alkyne groups to the click reaction was demonstrated using several dyes commonly employed in fluorescence microscopy and imaging (Cy3, ATTO-740, and coumarin 343). In order to establish the suitability of these copolymers as nanocarriers, copolymers were formulated into NPs, and cytocompatibility, cellular uptake, and visualization studies undertaken in HeLa cells. Dye-modified NPs exhibited no quenching, remained stable in solution for at least 10 days, showed no cytotoxicity, and were readily taken up by HeLa cells. Furthermore, in addition to enabling the incorporation of multiple fluorophores within the same NP through blending of individual dye-modified copolymers, dye-modified polyesters offer advantages over physical entrapment of dye, including improved signal to noise ratio and localization of the fluorescence signal within cells, and possess the necessary prerequisites for drug delivery and imaging.

  16. NEWS: Nuclear Emulsions for WIMP Search

    NASA Astrophysics Data System (ADS)

    Di Marco, Natalia; NEWS Collaboration

    2016-05-01

    In the field of direct Dark Matter search a different and promising approach is the directionality: the observation of the incoming apparent direction of WIMPs would in fact provide a new and unambiguous signature. The NEWS project is a very innovative approach for a high sensitivity experiment aiming at the directional detection of WIMPs: the detector is based on a novel emulsion technology called NIT (Nano Imaging Trackers) acting both as target and tracking device. In this paper we illustrate the features of a NIT-based detector and the newly developed read-out systems allowing to reach a spatial resolution of the order of 10 nm. We present the background studies and the experimental design. Finally we report about the time schedule of the experiment and the expected sensitivity for DM searches.

  17. Emulsion chamber observations and interpretation (HE 3)

    NASA Technical Reports Server (NTRS)

    Shibata, M.

    1986-01-01

    Experimental results from Emulsion Chamber (EC) experiments at mountain altitudes or at higher levels using flying carriers are examined. The physical interest in this field is concentrated on the strong interaction at the very high energy region exceeding the accelerator energy, also on the primary cosmic ray intensity and its chemical composition. Those experiments which observed cosmic ray secondaries gave information on high energy interaction characteristics through the analyses of secondary spectra, gamma-hadron families and C-jets (direct observation of the particle production occuring at the carbon target). Problems of scaling violation in fragmentation region, interaction cross section, transverse momentum of produced secondaries, and some peculiar features of exotic events are discussed.

  18. Recent applications of nuclear track emulsion

    NASA Astrophysics Data System (ADS)

    Mamatkulov, K. Z.; Ambřozová, I.; Artemenkov, D. A.; Bradnova, V.; Kamanin, D. V.; Kattabekov, R. R.; Majling, L.; Marey, A.; Ploc, O.; Rusakova, V. V.; Stanoeva, R.; Turek, K.; Zaitsev, A. A.; Zarubin, P. I.; Zarubina, I. G.

    2016-05-01

    Application of the nuclear track emulsion technique (NTE) in radioactivity and nuclear fission studies is discussed. It is suggested to use a HSP-1000 automated microscope for searching for a collinear cluster tri-partition of heavy nuclei implanted in NTE. Calibrations of α-particles and ion ranges in a novel NTE are carried out. Surface exposures of NTE samples to a Cf-252 source started. Planar events containing fragments and long-range α-particles as well as fragment triples only are studied. NTE samples are calibrated by ions Kr and Xe of energy of 1.2 and 3 A MeV. Use of the image recognition program "ImageJ" for obtaining characteristics of individual events and for events from the large scan area is presented.

  19. Biofilm Formation in Microscopic Double Emulsion Droplets

    NASA Astrophysics Data System (ADS)

    Chang, Connie; Weitz, David

    2012-02-01

    In natural, medical, and industrial settings, there exist surface-associated communities of bacteria known as biofilms. These highly structured films are composed of bacterial cells embedded within self-produced extracellular matrix, usually composed of exopolysaccharides, proteins, and nucleic acids; this matrix serves to protect the bacterial community from antibiotics and environmental stressors. Here, we form biofilms encapsulated within monodisperse, microscopically-sized double emulsion droplets using microfluidics. The bacteria self-organize at the inner liquid-liquid droplet interfaces, multiply, and differentiate into extracellular matrix-producing cells, forming manifold three-dimensional shell-within-a-shell structures of biofilms, templated upon the inner core of spherical liquid droplets. By using microfluidics to encapsulate bacterial cells, we have the ability to view individual cells multiplying in microscopically-sized droplets, which allows for high-throughput analysis in studying the genetic program leading to biofilm development, or cell signaling that induces differentiation.

  20. Active Emulsions: Synchronization of Chemical Oscillators

    NASA Astrophysics Data System (ADS)

    Fraden, Seth

    2012-02-01

    We explore the dynamical behavior of emulsions consisting of nanoliter volume droplets of the oscillatory Belousov-Zhabotinsky (BZ) reaction separated by a continuous oil phase. Some of the aqueous BZ reactants partition into the oil leading to chemical coupling of the drops. We use microfluidics to vary the size, composition and topology of the drops in 1D and 2D. Addition of a light sensitive catalyst to the drops and illumination with a computer projector allows each drop to be individually perturbed. A variety of synchronous regimes are found that systematically vary with the coupling strength and whether coupling is dominated by activatory or inhibitory species. In 1D we observe in- and anti-phase oscillations, stationary Turing patterns in which drops stop oscillating, but form spatially periodic patterns of drops in the oxidized and reduced states, and more complex combinations of stationary and oscillatory drops. In 2D, the attractors are more complex and vary with network topology and coupling strength. For hexagonal lattices as a function of increasing coupling strength we observe right and left handed rotating oscillations, mixed oscillatory and Turing states and finally full Turing states. Reaction -- diffusion models based on a simplified description of the BZ chemistry and diffusion of messenger species reproduce a number of the experimental results. For a range of parameters, a simplified phase oscillator model provides an intuitive understanding of the complex synchronization patterns. [4pt] ``Coupled oscillations in a 1D emulsion of Belousov--Zhabotinsky droplets,'' Jorge Delgado, Ning Li, Marcin Leda, Hector O. Gonzalez-Ochoa, Seth Fraden and Irving R. Epstein, Soft Matter, 7, 3155 (2011).

  1. Monolithic microextraction tips by emulsion photopolymerization.

    PubMed

    Liang, Shih-Shin; Chen, Shu-Hui

    2009-03-20

    Monoliths formed by photopolymerization are excellent means for fabricating functional elements in miniaturized microdevices such as microextraction tips which are becoming important for sample preparation. Various silica-based and polymer-based materials have been used to fabricate monoliths with through pores of several nm to 4 microm. However, the back pressure created by such methods is still considered to be high for microtips that use suction forces to deliver the liquid. In this study, we demonstrated that emulsion techniques such as oil-in-water can be used to form monoliths with large through pores (>20 microm), and with rigid structures on small (10 microL) and large (200 microL) pipette tips by photopolymerization. We further showed that, with minor modifications, various functionalized particles (5-20 microm) can be added to form stable emulsions and successfully encapsulated into the monoliths for qualitative and quantitative solid-phase microextractions for a diverse application. Due to high permeability and large surface area, quick equilibration can be achieved by pipetting to yield high recovery rates. Using tryptic digests of ovalbumin as the standard, we obtained a recovery yield of 90-109% (RSD: 10-16%) with a loading capacity of 3 mug for desalting tips immobilized with C18 beads. Using tryptic digests of beta-casein and alpha-casein as standards, we showed that phosphopeptides were substantially enriched by tips immobilized with immobilized metal affinity chromatography or TiO(2) materials. Using estrogenic compounds as standards, we obtained a recovery yield of 95-108% (RSD: 10-12%) and linear calibration curves ranging from 5 to 100 ng (R(2)>0.99) for Waters Oasis HLB tips immobilized with hydrophilic beads. PMID:19203757

  2. Uranyl ion uptake capacity of poly (N-isopropylacrylamide/maleic acid) copolymeric hydrogels prepared by gamma rays

    NASA Astrophysics Data System (ADS)

    Kam, Erol; Taşdelen, Betul; Osmanlioglu, A. Erdal

    2012-06-01

    The effect of gel composition, absorbed dose and pH of the solution on the uranyl ion uptake capacity of N-isopropylacrylamide/maleic acid copolymeric hydrogels containing 0-3 mol% of maleic acid at 48 kGy have been investigated. Uranyl uptake capacity of hydrogels are found to increase from 18.5 to 94.8 mg [UO22+]/g dry gel as the mole % of maleic acid content in the gel structure increased from 0 to 3. The percent swelling, equilibrium swelling and diffusion coefficient values have been evaluated for poly(N-isopropylacrylamide/maleic acid) hydrogels at 500 ppm of uranyl nitrate solution.

  3. Stabilizing oil-in-water emulsions with regenerated chitin nanofibers.

    PubMed

    Zhang, Ying; Chen, Zhigang; Bian, Wenyang; Feng, Li; Wu, Zongwei; Wang, Peng; Zeng, Xiaoxiong; Wu, Tao

    2015-09-15

    Natural chitin is a highly crystalline biopolymer with poor aqueous solubility. Thus direct application of chitin is rather limited unless chemical modifications are made to improve its solubility in aqueous media. Through a simple dissolution and regeneration process, we have successfully prepared chitin nanofibers with diameters around 50nm, which form a stable suspension at concentrations higher than 0.50% and a self-supporting gel at concentrations higher than 1.00%. Additionally, these nanofibers can stabilize oil-in-water emulsions with oil fraction more than 0.50 at chitin usage level of 0.01g/g oil. The droplet sizes of the resulting emulsions decrease with increasing chitin concentrations and decreasing oil fraction. Confocal laser scanning micrographs demonstrate the adsorption of chitin nanofibers on the emulsion droplet surface, which indicates the emulsion stabilization is through a Pickering mechanism. Our findings allow the direct application of chitin in the food industry without chemical modifications.

  4. Emulsion Polymerization of Butyl Acrylate: Spin Trapping and EPR Study

    NASA Technical Reports Server (NTRS)

    Kim, S.; Westmoreland, D.

    1994-01-01

    The propagating radical in the emulsion polymerization reaction of butyl acrylate was detected by Electron Paramagnetic Resonance spectroscopy using two spin trapping agents, 2-methyl-2nitrosopropane and alpha -N-tert-butylnitrone.

  5. Pickering emulsions stabilized by paraffin wax and Laponite clay particles.

    PubMed

    Li, Caifu; Liu, Qian; Mei, Zhen; Wang, Jun; Xu, Jian; Sun, Dejun

    2009-08-01

    Emulsions containing wax in dispersed droplets stabilized by disc-like Laponite clay particles are prepared. Properties of the emulsions prepared at different temperatures are examined using stability, microscopy and droplet-size analysis. At low temperature, the wax crystals in the oil droplets can protrude through the interface, leading to droplet coalescence. But at higher temperatures, the droplet size decreases with wax concentration. Considering the viscosity of the oil phase and the interfacial tension, we conclude that the wax is liquid-like during the high temperature emulsification process, but during cooling wax crystals appear around the oil/water interface and stabilize the droplets. The oil/water ratio has minimal effect on the emulsions between ratios of 3:7 and 7:3. The Laponite is believed to stabilize the emulsions by increasing the viscosity of the continuous phase and also by adsorbing at the oil/water interface, thus providing a physical barrier to coalescence. PMID:19428022

  6. Pickering emulsions stabilized by paraffin wax and Laponite clay particles.

    PubMed

    Li, Caifu; Liu, Qian; Mei, Zhen; Wang, Jun; Xu, Jian; Sun, Dejun

    2009-08-01

    Emulsions containing wax in dispersed droplets stabilized by disc-like Laponite clay particles are prepared. Properties of the emulsions prepared at different temperatures are examined using stability, microscopy and droplet-size analysis. At low temperature, the wax crystals in the oil droplets can protrude through the interface, leading to droplet coalescence. But at higher temperatures, the droplet size decreases with wax concentration. Considering the viscosity of the oil phase and the interfacial tension, we conclude that the wax is liquid-like during the high temperature emulsification process, but during cooling wax crystals appear around the oil/water interface and stabilize the droplets. The oil/water ratio has minimal effect on the emulsions between ratios of 3:7 and 7:3. The Laponite is believed to stabilize the emulsions by increasing the viscosity of the continuous phase and also by adsorbing at the oil/water interface, thus providing a physical barrier to coalescence.

  7. Productivity improvements in longhole stoping with repumpable emulsions

    SciTech Connect

    Thorpe, R.

    1994-12-31

    Bulk emulsion explosives have been used at surface mines and quarries for many years. Recently, this technology has been adapted for underground use in relatively confined work areas and in smaller diameter blastholes. From November 1992 to April 1993, approximately 20 tons of emulsion was successfully pumped and blasted in longhole stopes at Westmin`s HW Mine. This demonstration was undertaken to determine if the use of repumpable emulsions could improve productivity compared to conventional loading. Hole diameters were 54 mm, 76 mm and 89 mm, up to 24 m in length, and oriented from vertically up to vertically down. In each ring of holes, the collars were staggered to maintain a constant powder factor. Compared to gravity or pneumatically loading ANFO or cartridged explosives, repumpable emulsions have been loaded two to four times faster, in stoping operations. Other factors considered in this program were operating costs, physical effort required of the loading crew, efficiency, waste control and safety.

  8. Fluorescent-magnetic Janus particles prepared via seed emulsion polymerization.

    PubMed

    Kaewsaneha, Chariya; Bitar, Ahmad; Tangboriboonrat, Pramuan; Polpanich, Duangporn; Elaissari, Abdelhamid

    2014-06-15

    Anisotropic polymeric colloidal or Janus particles possessing simultaneous magnetic and fluorescent properties were successfully prepared via the swelling-diffusion or the in situ emulsion polymerization method. In the swelling-diffusion process, magnetic emulsions (an organic ferrofluid dispersed in aqueous medium) were synthesized and used for seeds of submicron magnetic Janus particles. After swelling the anisotropic particles obtained by 1-pyrene-carboxaldehyde fluorescent dye dissolved in tetrahydrofuran, well-defined fluorescent-magnetic Janus particles were produced. In the in situ emulsion polymerization, styrene monomer mixed with fluorescent dye monomers, i.e., 1-pyrenylmethyl methacrylate (PyMMA) or fluorescein dimethacrylate (FDMA), and an oil-soluble initiator (2,2'-azobis(2-isobutyronitrile)) were emulsified in the presence of magnetic seed emulsions. The confocal microscopic images showed the fluorescent-magnetic Janus particles with high fluorescent intensity when a fluorescent crosslinker monomer FDMA was employed. PMID:24767504

  9. Chemical Demulsification of Water-in-Crude Oil Emulsions

    NASA Astrophysics Data System (ADS)

    Abdurahman; Nour, H.; Mohd Yunus, Rosli; Jemaat, Zulkifly

    Demulsification (emulsion breaking) is necessary in many practical applications such as the petroleum industry, painting and waste-water treatment in environmental technology. Chemical demulsification is the most widely applied method of treating water-in-crude oil emulsions and involves the use of chemical additives to accelerate the emulsion breaking process. The effect of chemical demulsification operations on the stability and properties of water-in-crude oil emulsions was assessed experimentally. In this regard, Amine Demulsifier, Polyhydric Alcohol, Acid and Polymeric demulsifiers were used. Using samples of w/o, the data presented for several commercial-type demulsifiers show a strong connection (correlation) between good performance (fast coalescence) and the demulsifiers. The relative rates of water separation were characterized via beaker tests. The amine group demulsifiers promoted best coalescence of droplets. In contrast, polymeric demulsifier group is the least in water separation.

  10. Image Charge Effects on the Formation of Pickering Emulsions.

    PubMed

    Wang, Hongzhi; Singh, Virendra; Behrens, Sven Holger

    2012-10-18

    Vigorous mixing of an aqueous particle dispersion with oil usually produces a particle-stabilized emulsion (a "Pickering emulsion"), the longevity of which depends on the particles' wetting properties. A known exception occurs when particles fail to adsorb to the oil-water interface created during mixing because of a strong repulsion between charges on the particle surface and similar charges on the oil-water interface; in this case, no Pickering emulsion is formed. Here, we present experimental evidence that the rarely considered electrostatic image force can cause a much bigger hindrance to particle adsorption and prevent the formation of Pickering emulsions even when the particle interaction with the interface charge is attractive. A simple theoretical estimate confirms the observed magnitude of this effect and points at an important limitation of Pickering emulsification, a technology with widespread industrial applications and increasing popularity in materials research and development.

  11. Microfluidic production of multiple emulsions and functional microcapsules.

    PubMed

    Lee, Tae Yong; Choi, Tae Min; Shim, Tae Soup; Frijns, Raoul A M; Kim, Shin-Hyun

    2016-09-21

    Recent advances in microfluidics have enabled the controlled production of multiple-emulsion drops with onion-like topology. The multiple-emulsion drops possess an intrinsic core-shell geometry, which makes them useful as templates to create microcapsules with a solid membrane. High flexibility in the selection of materials and hierarchical order, achieved by microfluidic technologies, has provided versatility in the membrane properties and microcapsule functions. The microcapsules are now designed not just for storage and release of encapsulants but for sensing microenvironments, developing structural colours, and many other uses. This article reviews the current state of the art in the microfluidic-based production of multiple-emulsion drops and functional microcapsules. The three main sections of this paper discuss distinct microfluidic techniques developed for the generation of multiple emulsions, four representative methods used for solid membrane formation, and various applications of functional microcapsules. Finally, we outline the current limitations and future perspectives of microfluidics and microcapsules. PMID:27470590

  12. Reduced Fat Food Emulsions: Physicochemical, Sensory, and Biological Aspects.

    PubMed

    Chung, Cheryl; Smith, Gordon; Degner, Brian; McClements, David Julian

    2016-01-01

    Fat plays multiple important roles in imparting desirable sensory attributes to emulsion-based food products, such as sauces, dressings, soups, beverages, and desserts. However, there is concern that over consumption of fats leads to increased incidences of chronic diseases, such as obesity, coronary heart disease, and diabetes. Consequently, there is a need to develop reduced fat products with desirable sensory profiles that match those of their full-fat counterparts. The successful design of high quality reduced-fat products requires an understanding of the many roles that fat plays in determining the sensory attributes of food emulsions, and of appropriate strategies to replace some or all of these attributes. This paper reviews our current understanding of the influence of fat on the physicochemical and physiological attributes of food emulsions, and highlights some of the main approaches that can be used to create high quality emulsion-based food products with reduced fat contents.

  13. Dehydration of oil waste emulsions by means of flocculants

    SciTech Connect

    Gandurina, L.V.; Butseva, L.N.; Shtondina, V.S.

    1995-05-01

    Oil waste emulsions are formed in the course of pumping petroleum crudes and products and are collected from the surfaces of equipment in recirculating water systems and wastewater disposal facilities (oil separators, sand traps, oil traps, holding pits for accidental spills, settlers, ponds, sludge accumulators, and so on). Emulsions are also obtained in the course of cleaning equipment in crude oil desalting and dehydration units. Such emulsions are stable, structurized systems that are very resistant to dewatering by heating and settling in separator tanks. In order to break stabilized emulsions, i.e., in order to ensure complete coalescence of drops when they collide, it is not sufficient to increase the forces of mutual attraction of drops at the moment of collision; in addition, the protective shell must be either destroyed or weakened. Demulsifying agents, or surfactants, will displace the stabilizers. This report is concerned with demulsifier efficiency.

  14. Tocopherol and tocotrienol homologs in parenteral lipid emulsions

    PubMed Central

    Xu, Zhidong; Harvey, Kevin A; Pavlina, Thomas M; Zaloga, Gary P; Siddiqui, Rafat A

    2015-01-01

    Parenteral lipid emulsions, which are made of oils from plant and fish sources, contain different types of tocopherols and tocotrienols (vitamin E homologs). The amount and types of vitamin E homologs in various lipid emulsions vary considerably and are not completely known. The objective of this analysis was to develop a quantitative method to determine levels of all vitamin E homologs in various lipid emulsions. An HPLC system was used to measure vitamin E homologs using a Pinnacle DB Silica normal phase column and an isocratic, n-hexane:1,4 dioxane (98:2) mobile phase. An optimized protocol was used to report vitamin E homolog concentrations in soybean oil-based (Intralipid®, Ivelip®, Lipofundin® N, Liposyn® III, and Liposyn® II), medium- and long-chain fatty acid-based (Lipofundin®, MCT and Structolipid®), olive oil-based (ClinOleic®), and fish oil-based (Omegaven®) and mixture of these oils-based (SMOFlipid®, Lipidem®) commercial parenteral lipid emulsions. Total content of all vitamin E homologs varied greatly between different emulsions, ranging from 57.9 to 383.9 µg/mL. Tocopherols (α, β, γ, δ) were the predominant vitamin E homologs for all emulsions, with tocotrienol content < 0.3%. In all of the soybean emulsions, except for Lipofundin® N, the predominant vitamin E homolog was γ-tocopherol, which ranged from 57–156 µg/mL. ClinOleic® predominantly contained α-tocopherol (32 µg/mL), whereas α-tocopherol content in Omegaven® was higher than most of the other lipid emulsions (230 µg/mL). Practical applications The information on the types and quantity of vitamin E homologs in various lipid emulsions will be extremely useful to physicians and healthcare personnel in selecting appropriate lipid emulsions that are exclusively used in patients with inadequate gastrointestinal function, including hospitalized and critically ill patients. Some emulsions may require vitamin E supplementation in order to meet minimal human requirements

  15. 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

  16. Enhanced reductive dechlorination in columns treated with edible oil emulsion

    NASA Astrophysics Data System (ADS)

    Long, Cameron M.; Borden, Robert C.

    2006-09-01

    The effect of edible oil emulsion treatment on enhanced reductive dechlorination was evaluated in a 14 month laboratory column study. Experimental treatments included: (1) emulsified soybean oil and dilute HCl to inhibit biological activity; (2) emulsified oil only; (3) emulsified oil and anaerobic digester sludge; and (4) continuously feeding soluble substrate. A single application of emulsified oil was effective in generating strongly reducing, anaerobic conditions for over 14 months. PCE was rapidly reduced to cis-DCE in all three live columns. Bioaugmentation with a halorespiring enrichment culture resulted in complete dechlorination of PCE to ethene in the soluble substrate column (yeast extract and lactate). However, an additional treatment with a pulse of yeast extract and bioaugmentation culture was required to stimulate complete dechlorination in the emulsion treated columns. Once the dechlorinating population was established, the emulsion only column degraded PCE from 90-120 μM to below detection with concurrent ethene production in a 33 day contact time. The lower biodegradation rates in the emulsion treated columns compared to the soluble substrate column suggest that emulsified oil barriers may require a somewhat longer contact time for effective treatment. In the HCl inhibited column, partitioning of PCE to the retained oil substantially delayed PCE breakthrough. However, reduction of PCE to more soluble degradation products ( cis-DCE, VC and ethene) greatly reduced the impact of oil-water partitioning in live columns. There was only a small decline in the hydraulic conductivity ( K) of column #1 (low pH + emulsion, Kfinal/ Kinitial = 0.57) and column #2 (live + emulsion, Kfinal/ Kinitial = 0.73) indicating emulsion injection did not result in appreciable clogging of the clayey sand. However, K loss was greater in column #3 (sludge +emulsion, Kfinal/ Kinitial = 0.12) and column #4 (soluble substrate, Kfinal/ Kinitial = 0.03) indicating clogging due

  17. Imaging contrast effects in alginate microbeads containing trapped emulsion droplets.

    PubMed

    Hester-Reilly, Holly J; Shapley, Nina C

    2007-09-01

    This study focuses on spherical microparticles made of cross-linked alginate gel and microcapsules composed of an oil-in-water emulsion where the continuous aqueous phase is cross-linked into an alginate gel matrix. We have investigated the use of these easily manufactured microbeads as contrast agents for the study of the flow properties of fluids using nuclear magnetic resonance imaging. Results demonstrate that combined spin-spin (T(2)) relaxation and diffusion contrast in proton NMR imaging can be used to distinguish among rigid polymer particles, plain alginate beads, and alginate emulsion beads. Multi-echo CPMG spin-echo imaging indicates that the average spin-lattice (T(1)) and spin-spin (T(2)) relaxation times of the plain alginate and alginate emulsion beads are comparable. Meanwhile, diffusion-weighted imaging produces sharp contrast between the two types of alginate beads, due to restricted diffusion inside the embedded oil droplets of the alginate emulsion beads. While the signal obtained from most materials is severely attenuated under applied diffusion gradients, the alginate emulsion beads maintain signal strength. The alginate emulsion beads were added to a suspension and imaged in an abrupt, annular expansion flow. The emulsion beads could be clearly distinguished from the surrounding suspending fluid and rigid polystyrene particles, through either T(2) relaxation or diffusion contrast. Such a capability allows future use of the alginate emulsion beads as tracer particles and as one particle type among many in a multimodal suspension where detailed concentration profiles or particle size separation must be quantified during flow. PMID:17600742

  18. Formation and stability of polychlorinated biphenyl Pickering emulsions

    NASA Astrophysics Data System (ADS)

    Roy-Perreault, Andréanne; Kueper, Bernard H.; Rawson, Jim

    2005-03-01

    An emulsion stabilized by colloidal suspensions of finely divided solids is known as a Pickering emulsion. The potential for polychlorinated biphenyls (PCBs) to form Pickering emulsions ex situ when in contact with powdered solids, such as clays and metal oxides, is investigated here. Bentonite, iron oxide and magnesium oxide dispersions proved to be robust Pickering emulsion stabilizers, whereas manganese oxide dispersions were not. Batch experiments revealed that emulsions can be formed using a moderately low energy input and can be stabilized with solid concentrations as low as 0.5 wt.%. For the base conditions (volumetric oil fraction ( ϕoil)=30 vol.%; solid concentration ( χ)=2 wt.%), the formed emulsions were indefinitely stable and the initial average droplet diameters varied from 80 to 258 μm, depending on the solid used in the colloidal dispersion. The average droplet size varied at early time, but for most conditions stabilized to a steady-state value 1 week after preparation. The effect of Ostwald ripening was limited. At greater than 0.5 wt.% concentration, the efficiency of the solid dispersion as a stabilizer was dependant on the volumetric oil fraction but not on the solid concentration. Generally, systems with volumetric oil fractions outside of the 20-70 vol.% range were unstable. The emulsions' droplet stability, average droplet size and size distribution were observed to vary as a function of the amount of energy provided to the system, the volumetric oil fraction, and the concentration of the solid in the aqueous dispersion. It is hypothesized that drilling through fractured rock in the immediate vicinity of dense, non-aqueous phase liquid (DNAPL) PCBs may provide both the energy and solid material necessary to form Pickering emulsions.

  19. Tunable Pickering emulsions with polymer-grafted lignin nanoparticles (PGLNs).

    PubMed

    Silmore, Kevin S; Gupta, Chetali; Washburn, Newell R

    2016-03-15

    Lignin is an abundant biopolymer that has native interfacial functions but aggregates strongly in aqueous media. Polyacrylamide was grafted onto kraft lignin nanoparticles using reversible addition-fragmentation chain transfer (RAFT) chemistry to form polymer-grafted lignin nanoparticles (PGLNs) that tune aggregation strength while retaining interfacial activities in forming Pickering emulsions. Polymer graft density on the particle surface, ionic strength, and initial water and cyclohexane volume fractions were varied and found to have profound effects on emulsion characteristics, including emulsion volume fraction, droplet size, and particle interfacial concentration that were attributed to changes in lignin aggregation and hydrophobic interactions. In particular, salt concentration was found to have a significant effect on aggregation, zeta potential, and interfacial tension, which was attributed to changes in solubility of both the kraft lignin and the polyacrylamide grafts. Dynamic light scattering, UV-vis spectroscopy, optical microscopy, and tensiometry were used to quantify emulsion properties and nanoparticle behavior. Under all conditions, the emulsions exhibited relatively fast creaming but were stable against coalescence and Ostwald ripening for a period of months. All emulsions were also oil-in-water (o/w) emulsions, as predicted by the Bancroft rule, and no catastrophic phase inversions were observed for any nanoparticle compositions. We conclude that lower grafting density of polyacrylamide on a lignin core resulted in high levels of interfacial activity, as characterized by higher concentration at the water-cyclohexane interface with a corresponding decrease in interfacial tension. These results indicate that the interfacial properties of polymer-grafted lignin nanoparticles are primarily due to the native hydrophobic interactions of the lignin core. These results suggest that the forces that drive aggregation are also correlated with interfacial

  20. Preparation of Pickering double emulsions using block copolymer worms.

    PubMed

    Thompson, Kate L; Mable, Charlotte J; Lane, Jacob A; Derry, Mathew J; Fielding, Lee A; Armes, Steven P

    2015-04-14

    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.

  1. Development of Nuclear Emulsion Detector for Muon Radiography

    NASA Astrophysics Data System (ADS)

    Nishio, A.; Morishima, K.; Kuwabara, K.; Nakamura, M.

    Muon radiography is the non-destructive testing technique of large-scale constructions with cosmic ray muon. Cosmic ray muon has high penetrating power and it always comes from the whole sky. In the same way of taking a X-ray photograph, we can obtain integrated density of constructions which thickness are several tens to several hundreds. We had ever applied this technique to nuclear reactors, volcanos, and so on. Nuclear emulsion is three dimensional track detector with micrometric position accuracy. Thanks to high position resolution, Nuclear emulsion has mrad angular resolution. In addition, the features which require no power supply and can observe in a large area suitable for muon radiography. In Nagoya University, we launched emulsion manufacturing equipment at 2010. It has become possible to flexible development of our detector and succeeded to development of high sensitive nuclear emulsion film (Nagoya emulsion). An important factor is the temperature characteristic to withstand the outdoor observation as a detector to be used in the muon radiography. There is a phenomenon of a latent image fading, whichit is well known in the photographic industry, and this phenomenon is known that temperature and water are involved. So we examined temperature and humidity characteristic of latent image fading about Nagoya emulsion. As a result, we found latent image fading is strongly depends on both temperature and humidity. By dehydrating emulsion film in RH8%, over 95% (Grain Density>40) detection efficiency of muon track keeps over 3months in 25degree, for 2months in 35degree. Additionally it was showed in this test that increasing back ground noise "fog", which may have occurred by sealing emulsion film in a narrow space, is reduced by buffer space in the bag.

  2. Generation of colloidal granules and capsules from double emulsion drops

    NASA Astrophysics Data System (ADS)

    Hess, Kathryn S.

    Assemblies of colloidal particles are extensively used in ceramic processing, pharmaceuticals, inks and coatings. In this project, the aim was to develop a new technique to fabricate monodispersed colloidal assemblies. The use of microfluidic devices and emulsion processing allows for the fabrication of complex materials that can be used in a variety of applications. A microfluidic device is used to create monodispersed water/oil/water (w/o/w) double emulsions with interior droplets of colloidal silica suspension ranging in size from tens to hundreds of microns. By tailoring the osmotic pressure using glycerol as a solute in the continuous and inner phases of the emulsion, we can control the final volume size of the monodispersed silica colloidal crystals that form in the inner droplets of the double emulsion. Modifying the ionic strength in the colloidal dispersion can be used to affect the particle-particle interactions and crystal formation of the final colloidal particle. This w/o/w technique has been used with other systems of metal oxide colloids and cellulose nanocrystals. Encapsulation of the colloidal suspension in a polymer shell for the generation of ceramic-polymer core-shell particles has also been developed. These core-shell particles have spawned new research in the field of locally resonant acoustic metamaterials. Systems and chemistries for creating cellulose hydrogels within the double emulsions have also been researched. Water in oil single emulsions and double emulsions have been used to create cellulose hydrogel spheres in the sub-100 micron diameter range. Oil/water/oil double emulsions allow us to create stable cellulose capsules. The addition of a second hydrogel polymer, such as acrylate or alginate, further strengthens the cellulose gel network and can also be processed into capsules and particles using the microfluidic device. This work could have promising applications in acoustic metamaterials, personal care products, pharmaceuticals

  3. Droplet-based microfluidics and the dynamics of emulsions

    NASA Astrophysics Data System (ADS)

    Baret, Jean-Christophe; Brosseau, Quentin; Semin, Benoit; Qu, Xiaopeng

    2012-02-01

    Emulsions are complex fluids already involved for a long time in a wide-range of industrial processes, such as, for example, food, cosmetics or materials synthesis [1]. More recently, applications of emulsions have been extended to new fields like biotechnology or biochemistry where the compartmentalization of compounds in emulsion droplets is used to parallelise (bio-) chemical reactions [2]. Interestingly, these applications pinpoint to fundamental questions dealing with surfactant dynamics, dynamic surface tension, hydrodynamic interactions and electrohydrodynamics. Droplet-based microfluidics is a very powerful tool to quantitatively study the dynamics of emulsions at the single droplet level or even at the single interface level: well-controlled emulsions are produced and manipulated using hydrodynamics, electrical forces, optical actuation and combination of these effects. We will describe here how droplet-based microfluidics is used to extract quantitative informations on the physical-chemistry of emulsions for a better understanding and control of the dynamics of these systems [3].[4pt] [1] J. Bibette et al. Rep. Prog. Phys., 62, 969-1033 (1999)[0pt] [2] A. Theberge et al., Angewandte Chemie Int. Ed. 49, 5846 (2010)[0pt] [3] J.-C. Baret et al., Langmuir, 25, 6088 (2009)

  4. Formulation, stability and degradation kinetics of intravenous cinnarizine lipid emulsion.

    PubMed

    Shi, Shuai; Chen, Hao; Cui, Yue; Tang, Xing

    2009-05-21

    Cinnarizine was loaded in the lipid emulsion to develop an intravenous formulation with good physical and chemical stability. High-pressure homogenization was used to prepare the lipid emulsion. The factors influencing the stability of cinnarizine lipid emulsion, such as different drug loading methods, pH, temperature, sterilization methods and sterilization time were monitored by high-performance liquid chromatograph. The degradation of cinnarizine in aqueous solution and lipid emulsion both followed apparent first-order kinetics. A possible degradation mechanism was postulated by the bell-shaped pH-rate profile of cinnarizine. Localization of the drug in the interfacial lecithin layer significantly improved the chemical stability of cinnarizine and its stabilizing mechanism was thoroughly discussed and proved. The activation energy of cinnarizine in lipid emulsion was calculated to be 51.27 kJ/mol which was similar to that in aqueous solution. This indicates that the stabilizing effect of the drug carrier on cinnarizine was not an alteration of the degradation reaction. In addition, shelf-life of cinnarizine in lipid emulsion was estimated to be 1471.6 days at 4 degrees C, which is much longer compared with 19.8 days in aqueous solution. The final products were stable enough to resist a 121 degrees C rotating steam sterilization for 15 min. PMID:19429300

  5. Analyzing Benzene and Cyclohexane Emulsion Droplet Collisions on Ultramicroelectrodes.

    PubMed

    Li, Yan; Deng, Haiqiang; Dick, Jeffrey E; Bard, Allen J

    2015-11-01

    We report the collisions of single emulsion oil droplets with extremely low dielectric constants (e.g., benzene, ε of 2.27, or cyclohexane, ε of 2.02) as studied via emulsion droplet reactor (EDR) on an ultramicroelectrode (UME). By applying appropriate potentials to the UME, we observed the electrochemical effects of single-collision signals from the bulk electrolysis of single emulsion droplets. Different hydrophobic redox species (ferrocene, decamethyl-ferrocene, or metalloporphyrin) were trapped in a mixed benzene (or cyclohexane) oil-in-water emulsion using an ionic liquid as the supporting electrolyte and emulsifier. The emulsions were prepared using ultrasonic processing. Spike-like responses were observed in each i-t response due to the complete electrolysis of all of the above-mentioned redox species within the droplet. On the basis of these single-particle collision results, the collision frequency, size distribution, i-t decay behavior of the emulsion droplets, and possible mechanisms are analyzed and discussed. This work demonstrated that bulk electrolysis can be achieved in a few seconds in these attoliter reactors, suggesting many applications, such as analysis and electrosynthesis in low dielectric constant solvents, which have a much broader potential window.

  6. Magnetic Pickering emulsions stabilized by Fe3O4 nanoparticles.

    PubMed

    Zhou, Jun; Qiao, Xiuying; Binks, Bernard P; Sun, Kang; Bai, Mingwen; Li, Yunlong; Liu, Yi

    2011-04-01

    Superparamagnetic Fe(3)O(4) nanoparticles prepared by a classical coprecipitation method were used as the stabilizer to prepare magnetic Pickering emulsions, and the effects of particle concentration, oil/water volume ratio, and oil polarity on the type, stability, composition, and morphology of these functional emulsions were investigated. The three-phase contact angle (θ(ow)) of the Fe(3)O(4) nanoparticles at the oil-water interface was evaluated using the Washburn method, and the results showed that for nonpolar and weakly polar oils of dodecane and silicone, θ(ow) is close to 90°, whereas for strongly polar oils of butyl butyrate and 1-decanol, θ(ow) is far below 90°. Inherently hydrophilic Fe(3)O(4) nanoparticles can be used to prepare stable dodecane-water and silicone-water emulsions, but they cannot stabilize butyl butyrate-water and decanol-water mixtures with macroscopic phase separation occurring, which is in good agreement with the contact angle data. Emulsions are of the oil-in-water type for both dodecane and silicone oil, and the average droplet size increases with an increase in the oil volume fraction. For stable emulsions, not all of the particles are adsorbed to drop interfaces; the fraction adsorbed decreases with an increase in the initial oil volume fraction. Changes in the particle concentration have no obvious influence on the stability of these emulsions, even though the droplet size decreases with concentration.

  7. Evaluation on oxidative stability of walnut beverage emulsions.

    PubMed

    Liu, Shuang; Liu, Fuguo; Xue, Yanhui; Gao, Yanxiang

    2016-07-15

    Walnut beverage emulsions were prepared with walnut kernels, mixed nonionic emulsifiers and xanthan gum. The effects of food antioxidants on the physical stability and lipid oxidation of walnut beverage emulsions were investigated. The results showed that tea polyphenols could not only increase the droplet size of the emulsions, but also enhance physical stability during the thermal storage at 62 ± 1 °C. However, water-dispersed oil-soluble vitamin E and enzymatically modified isoquercitrin obviously decreased the physical stability of the emulsion system during the thermal storage. BHT and natural antioxidant extract had scarcely influenced on the physical stability of walnut beverage emulsions. Tea polyphenols and BHT could significantly retard lipid oxidation in walnut beverage emulsions against thermal and UV light exposure during the storage. Vitamin E exhibited the prooxidant effect during the thermal storage and the antioxidant attribute during UV light exposure. Other food antioxidants had no significant effect on retarding lipid oxidation during thermal or light storage. PMID:26948632

  8. 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. PMID:27374517

  9. Parylene-encapsulated copolymeric membranes as localized and sustained drug delivery platforms.

    PubMed

    Chen, Mark; Huang, Houjin; Pierstorff, Erik; Shin, Eric; Robinson, Erik; Ho, Dean

    2009-10-01

    Parylene is a biologically inert material capable of being deposited in conformal nanoscale layers on virtually any surface, making it a viable structural material for the fabrication of drug delivery devices, as well as implant coatings, sensors, and other biomedical technologies. Here we explore its novel drug delivery applications by using parylene to package the polymethyloxazoline-polydimethylsiloxane-polymethyloxazoline (PMOXA-PDMS-PMOXA) block copolymer membrane of a nanoscale thickness (approximately 4 nm/layer) mixed with a therapeutic element, creating an active parylene-encapsulated copolymeric (APC) membrane for slow release drug delivery of dexamethasone (Dex), a potent anti-inflammatory and immunosuppressant synthetic glucocorticoid. Given current needs for localized therapeutic release for conditions such as cancer, post-surgical inflammation, wound healing, regenerative medicine, to name a few, this stand-alone and minimally invasive implantable technology may impact a broad range of medical scenarios. To evaluate the applicability of the APC membrane as a biocompatible drug delivery system, real-time polymerase chain reaction (RT-PCR) was performed to investigate the expression of cytokines that regulate cellular stress and inflammation as a result of in vitro RAW264.7 macrophage cell growth on the APC membrane. Significant decreases in relative mRNA levels of IL-6, TNF-alpha, and iNOS were observed. Dex functionalized APC membranes were further found to effectively slow-elute the drug via confocal microscopy, with a confirmed extended elution capability over a period of several days, undergoing phosphate buffered saline washes between time points. In addition, we examined the membrane surface through atomic force microscopy (AFM) to examine Dex/copolymer deposition, and to characterize the surface of the APC membrane. Furthermore, we evaluated the effects of incubation with the APC membrane in solution on macrophage growth behavior and cellular

  10. Free radical (co)polymerization of methyl methacrylate and styrene in room temperature ionic liquids

    NASA Astrophysics Data System (ADS)

    Zhang, Hongwei

    Conventional free radical polymerizations were carried out in a variety of room temperature ionic liquids (RTILs). Generally, methyl methacrylate (MMA) and styrene (St) were used as typical monomers to compare the polymerization behavior both in RTILs and in common volatile organic compound solvents (VOCs). In most cases, it was observed that both yields and molecular weights are enhanced in the RTIL. While we believe the "diffusion-controlled termination" mechanism makes the termination of the radical propagating chains difficult due to the highly viscous nature of RTIL, other researchers have suggested that the rapid polymerization rates are due to the high polarity of these reaction media. By employing more than a dozen RTILs with a wide range of anions and cations, we attempted to correlate the viscosity and polarity of the RTILs with the molecular weights and polymerization rates. This correlation was not successful, suggesting that other parameters may also play a role in affecting the polymerization behavior. Other kinds of polymerizations have also been attempted including nitroxide-mediated living radical polymerizations of St and MMA in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6), and redox initiation system initiated polymerization of MMA through redox pair formed by cation of trihexyl-tetradecyl-phosphonium bis(2,4,4-trimethylpentyl) phosphinate ([H3TDP] [(PM3) 2P]) and BPO. The formation of PSt-b-PMMA by sequential monomer addition through the standard free radical polymerization mechanism, using BPO as initiator, can be realized in [BMIM]PF6 due to the insolubility of polymerized first block---PSt in [BMIM]PF6. The macroradicals wrapped inside the chain coils have prolonged lifetimes because of the diminished termination, which allow some of these radicals to initiate polymerization of MMA at room temperature to form diblock copolymer. Solvents effects on reactivity ratios for free radical statistical copolymerization have been

  11. Comment to "The pharmacopeial evolution of Intralipid injectable emulsion in plastic containers: from a coarse to a fine emulsion".

    PubMed

    Ellborg, Anders; Ferreira, Denise; Mohammadnejad, Javad; Wärnheim, Torbjörn

    2010-06-15

    The droplet size distribution of 50 batches of multi-chamber bags containing the parenteral nutrition emulsions Intralipid (Kabiven and Kabiven Peripheral) or Structolipid (StructoKabiven and StructoKabiven Peripheral), respectively, has been investigated. The results show that the non-compounded lipid emulsions analysed are in compliance with the United States Pharmacopeia (USP) chapter 729, Method II limit for the droplet size distribution, PFAT(5)<0.05%.

  12. Mussel-inspired one-step copolymerization to engineer hierarchically structured surface with superhydrophobic properties for removing oil from water.

    PubMed

    Huang, Shouying

    2014-10-01

    In the present study, a superhydrophobic polyurethane (PU) sponge with hierarchically structured surface, which exhibits excellent performance in absorbing oils/organic solvents, was fabricated for the first time through mussel-inspired one-step copolymerization approach. Specifically, dopamine (a small molecular bioadhesive) and n-dodecylthiol were copolymerized in an alkaline aqueous solution to generate polydopamine (PDA) nanoaggregates with n-dodecylthiol motifs on the surface of the PU sponge skeletons. Then, the superhydrophobic sponge that comprised a hierarchical structured surface similar to the chemical/topological structures of lotus leaf was fabricated. The topological structures, surface wettability, and mechanical property of the sponge were characterized by scanning electron microscopy, contact angle experiments, and compression test. Just as a result of the highly porous structure, superhydrophobic property and strong mechanical stability, this sponge exhibited desirable absorption capability of oils/organic solvents (weight gains ranging from 2494% to 8670%), suggesting a promising sorbents for the removal of oily pollutants from water. Furthermore, thanks to the nonutilization of the complicated processes or sophisticated equipment, the fabrication of the superhydrophobic sponge seemed to be quite easy to scale up. All these merits make the sponge a competitive candidate when compared to the conventional absorbents, for example, nonwoven polypropylene fabric.

  13. Palladium(II)-catalyzed copolymerization of styrenes with carbon monoxide: mechanism of chain propagation and chain transfer.

    PubMed

    Rix, Francis C; Rachita, Michael J; Wagner, Mark I; Brookhart, Maurice; Milani, Barbara; Barborak, James C

    2009-11-01

    A mechanistic interpretation of the [(1,10-phenanthroline)Pd(CH(3))(CH(3)CN)](+)[BArF](-) (1a) and [(2,2'-bipyridine)Pd(CH(3))(CH(3)CN)](+)[BArF](-) (1b) (BArF = 3,5-(CF(3))(2)-C(6)H(3)) catalyzed perfectly alternating copolymerization of styrenes with CO is reported. The copolymerization in CH(2)Cl(2) or chlorobenzene has been found to be first order in styrene and inverse first order in CO concentrations. The microscopic steps involved in the catalytic cycle have been studied via low temperature NMR techniques. Palladium alkyl chelate complex [(2,2'-bipyridine)Pd(CHArCH(2)C(O)CH(3)](+)[BArF](-) (5b sigma) and [(2,2'-bipyridine)Pd(eta(3)-CH(CH(2)C(O)CH(3))Ar)](+)[BArF](-) (5b pi), existing in equilibrium, were prepared. Treatment of 5b sigma,pi with (13)CO followed by 4-tert-butylstyrene at -78 degrees C allowed for (13)C NMR monitoring of the alternating chain growth of a series of palladium acyl carbonyl complexes. The acyl carbonyl species, representing the catalyst resting state, is in equilibrium with a palladium acyl styrene complex. The equilibrium constant, K(4), measured between [(phen)Pd(CO)(C(O)CH(3)](+)[BArF](-) (3a) and [(phen)Pd(C(O)CH(3))-(C(6)H(5)C=CH(2))](+)[BArF](-) (8a), was determined to be 2.84 +/- 2.8 x 10(-7) at -66 degrees C. The barrier to migratory insertion in 8a was determined (DeltaG(double dagger) (-66 degrees C) = 15.6 +/- 0.1 kcal mol(-1)). From the experimentally determined kinetic and thermodynamic data for the copolymerization of styrene with CO a mechanistic model has been constructed. The ability of this model to predict catalyst turnover frequency (TOF) was used as a test of its validity. A series of para-substituted styrenes, p-XC(6)H(4)CH=CH(2) (X = -OCH(3), -CH(3), -H, -Cl), were copolymerized with CO. A Hammett treatment of TOF for the series showed that electron-donating groups increase the rate of copolymerization (rho p = -0.8). The ratio of chain transfer to chain propagation was found to increase with styrene

  14. Topological defects and interactions in nematic emulsions

    NASA Astrophysics Data System (ADS)

    Lubensky, T. C.; Pettey, David; Currier, Nathan; Stark, Holger

    1998-01-01

    Inverse nematic emulsions, in which surfactant-coated water droplets are dispersed in a nematic host fluid, have distinctive properties that set them apart from dispersions of two isotropic fluids or of nematic droplets in an isotropic fluid. We present a comprehensive theoretical study of the distortions produced in the nematic host by the dispersed droplets and of solvent-mediated dipolar interactions between droplets that lead to their experimentally observed chaining. A single droplet in a nematic host acts like a macroscopic hedgehog defect. Global boundary conditions force the nucleation of compensating topological defects in the nematic host. Using variational techniques, we show that in the lowest energy configuration, a single water droplet draws a single hedgehog out of the nematic host to form a tightly bound dipole. Configurations in which the water droplet is encircled by a disclination ring have higher energy. The droplet dipole induces distortions in the nematic host that lead to an effective dipole-dipole interaction between droplets, and hence to chaining.

  15. The morphology of emulsion polymerized latex particles

    SciTech Connect

    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 structre 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/ < M < 6 x 10/sup 6/ g/mol. For M > 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. 25 refs., 6 figs., 3 tabs.

  16. 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.

  17. Phagocytosis of immunoglobulin-coated emulsion droplets.

    PubMed

    Ben M'Barek, Kalthoum; Molino, Diana; Quignard, Sandrine; Plamont, Marie-Aude; Chen, Yong; Chavrier, Philippe; Fattaccioli, Jacques

    2015-05-01

    Phagocytosis by macrophages represents a fundamental process essential for both immunity and tissue homeostasis. The size of targets to be eliminated ranges from small particles as bacteria to large objects as cancerous or senescent cells. Most of our current quantitative knowledge on phagocytosis is based on the use of solid polymer microparticles as model targets that are well adapted to the study of phagocytosis mechanisms that do not involve any lateral mobility of the ligands, despite the relevance of this parameter in the immunological context. Herein we designed monodisperse, IgG-coated emulsion droplets that are efficiently and specifically internalized by macrophages through in-vitro FcγR-mediated phagocytosis. We show that, contrary to solid polymeric beads, droplet uptake is efficient even for low IgG densities, and is accompagnied by the clustering of the opsonins in the zone of contact with the macrophage during the adhesion step. Beyond the sole interest in the design of the material, our results suggest that lateral mobility of proteins at the interface of a target greatly enhances the phagocytic uptake.

  18. Biocompatible amphiphilic pentablock copolymeric nanoparticles for anti-cancer drug delivery.

    PubMed

    Byagari, K; Shanavas, A; Rengan, A K; Kundu, G C; Srivastava, R

    2014-01-01

    A pentablock copolymer of Poly(Lactide-co-Glycolide) and Pluronic F68 was synthesized using ring-opening polymerization and characterized by NMR and FTIR for confirming the structure of the block copolymer. TG-DTA studies showed PLGA:Pluronic ratio to be 4:1. As the PLGA-PEO-PPO-PEO-PLGA Pentablock Copolymer (PPPC) prepared is amphiphilic, its Critical Vesicular Concentration, was measured, which was lower at 37 degrees C than at 25 degrees C, which could provide better stability to the system at physiological temperature. The nanoparticles of PPPC vary in topographyand range from 150 to 500 nm in size, according to the synthesis route used viz Emulsion Solvent Evaporation and simple dialysis. Pentablock copolymer nanoparticles were found to entrap about 84% of hydrophobic drug, docetaxel. Drug release profile of docetaxel showed about 50% release in first 2 hours at pH 4.6 and about 80% docetaxel was released at pH 7.4, at the end of 2 days. The PPPC nanoparticles was found to be biocompatible to L929 cell lines up to 1 mg/ml concentration. Preliminary in vitro cytotoxic effect of docetaxel loaded PPPC nanoparticles against four different cancer cell lines showed 50% inhibitory concentration of 6 nM in A431 (Squamous cell carcinoma), 250 nM in HeLa (Cervical carcinoma), 800 nM in PC3 (Prostate carcinoma) and 1 microM in KB (Epidermoid carcinoma) cells. PMID:24724503

  19. Dynamically reconfigurable complex emulsions via tunable interfacial tensions.

    PubMed

    Zarzar, Lauren D; Sresht, Vishnu; Sletten, Ellen M; Kalow, Julia A; Blankschtein, Daniel; Swager, Timothy M

    2015-02-26

    Emulsification is a powerful, well-known technique for mixing and dispersing immiscible components within a continuous liquid phase. Consequently, emulsions are central components of medicine, food and performance materials. Complex emulsions, including Janus droplets (that is, droplets with faces of differing chemistries) and multiple emulsions, are of increasing importance in pharmaceuticals and medical diagnostics, in the fabrication of microparticles and capsules for food, in chemical separations, in cosmetics, and in dynamic optics. Because complex emulsion properties and functions are related to the droplet geometry and composition, the development of rapid, simple fabrication approaches allowing precise control over the droplets' physical and chemical characteristics is critical. Significant advances in the fabrication of complex emulsions have been made using a number of procedures, ranging from large-scale, less precise techniques that give compositional heterogeneity using high-shear mixers and membranes, to small-volume but more precise microfluidic methods. However, such approaches have yet to create droplet morphologies that can be controllably altered after emulsification. Reconfigurable complex liquids potentially have great utility as dynamically tunable materials. Here we describe an approach to the one-step fabrication of three- and four-phase complex emulsions with highly controllable and reconfigurable morphologies. The fabrication makes use of the temperature-sensitive miscibility of hydrocarbon, silicone and fluorocarbon liquids, and is applied to both the microfluidic and the scalable batch production of complex droplets. We demonstrate that droplet geometries can be alternated between encapsulated and Janus configurations by varying the interfacial tensions using hydrocarbon and fluorinated surfactants including stimuli-responsive and cleavable surfactants. This yields a generalizable strategy for the fabrication of multiphase emulsions with

  20. Dynamically reconfigurable complex emulsions via tunable interfacial tensions

    PubMed Central

    Zarzar, Lauren D.; Sresht, Vishnu; Sletten, Ellen M.; Kalow, Julia A.; Blankschtein, Daniel; Swager, Timothy M.

    2015-01-01

    Emulsification is a powerful, well-known technique for mixing and dispersing immiscible components within a continuous liquid phase. Consequently, emulsions are central components of medicine, food and performance materials. Complex emulsions, including multiple emulsions and Janus droplets which contain hemispheres of differing material, are of increasing importance1 in pharmaceuticals and medical diagnostics2, in the fabrication of microparticles and capsules3–5 for food6, in chemical separations7, in cosmetics8, and in dynamic optics9. Because complex emulsion properties and functions are related to the droplet geometry and composition, the development of rapid, simple fabrication approaches allowing precise control over the droplets’ physical and chemical characteristics is critical. Significant advances in the fabrication of complex emulsions have been made using a number of procedures, ranging from large-scale, less precise techniques that give compositional heterogeneity using high-shear mixers and membranes10, to small-volume but more precise microfluidic methods11,12. However, such approaches have yet to create droplet morphologies that can be controllably altered after emulsification. Reconfigurable complex liquids potentially have greatly increased utility as dynamically tunable materials. Here we describe an approach to the one-step fabrication of three- and four-phase complex emulsions with highly controllable and reconfigurable morphologies. The fabrication makes use of the temperature-sensitive miscibility of hydrocarbon, silicone and fluorocarbon liquids, and is applied to both the microfluidic and the scalable batch production of complex droplets. We demonstrate that droplet geometries can be alternated between encapsulated and Janus configurations by varying the interfacial tensions using hydrocarbon and fluorinated surfactants including stimuli-responsive and cleavable surfactants. This yields a generalizable strategy for the fabrication of

  1. Food-grade Pickering emulsions stabilised with solid lipid particles.

    PubMed

    Pawlik, Aleksandra; Kurukji, Daniel; Norton, Ian; Spyropoulos, Fotis

    2016-06-15

    Aqueous dispersions of tripalmitin particles (with a minimum size of 130 nm) were produced, via a hot sonication method, with and without the addition of food-grade emulsifiers. Depending on their relative size and chemistry, the emulsifiers altered the properties of the fat particles (e.g. crystal form, dispersion state and surface properties) by two proposed mechanisms. Firstly, emulsifiers modify the rate and/or extent of polymorphic transitions, resulting in the formation of fat crystals with a range of polarities. Secondly, the adsorption of emulsifiers at the particle interface modifies crystal surface properties. Such emulsifier-modified fat particles were then used to stabilise emulsions. As the behaviour of these particles was predisposed by the kind of emulsifier employed for their manufacture, the resulting particles showed different preferences to which of the emulsion phases (oil or water) became the continuous one. The polarity of the fat particles decreased as follows: Whey Protein Isolate > Soy Lecithin > Soy Lecithin + Tween 20 > Tween 20 > Polyglycerol Polyricinoleate > no emulsifier. Consequently, particles stabilised with WPI formed oil-in-water emulsions (O/W); particles stabilised solely with lecithin produced a highly unstable W/O emulsion; and particles stabilised with a mixture of lecithin and Tween 20 gave a stable W/O emulsion with drop size up to 30 μm. Coalescence stable, oil-continuous emulsions (W/O) with drop sizes between 5 and 15 μm were produced when the tripalmitin particles were stabilised with solely with Tween 20, solely with polyglycerol polyricinoleate, or with no emulsifier at all. It is proposed that the stability of the latter three emulsions was additionally enhanced by sintering of fat particles at the oil-water interface, providing a mechanical barrier against coalescence. PMID:27198879

  2. Breaking oil-in-water emulsions stabilized by yeast.

    PubMed

    Furtado, Guilherme F; Picone, Carolina S F; Cuellar, Maria C; Cunha, Rosiane L

    2015-04-01

    Several biotechnological processes can show an undesirable formation of emulsions making difficult phase separation and product recovery. The breakup of oil-in-water emulsions stabilized by yeast was studied using different physical and chemical methods. These emulsions were composed by deionized water, hexadecane and commercial yeast (Saccharomyces cerevisiae). The stability of the emulsions was evaluated varying the yeast concentration from 7.47 to 22.11% (w/w) and the phases obtained after gravity separation were evaluated on chemical composition, droplet size distribution, rheological behavior and optical microscopy. The cream phase showed kinetic stability attributed to mechanisms as electrostatic repulsion between the droplets, a possible Pickering-type stabilization and the viscoelastic properties of the concentrated emulsion. Oil recovery from cream phase was performed using gravity separation, centrifugation, heating and addition of demulsifier agents (alcohols and magnetic nanoparticles). Long centrifugation time and high centrifugal forces (2 h/150,000×g) were necessary to obtain a complete oil recovery. The heat treatment (60°C) was not enough to promote a satisfactory oil separation. Addition of alcohols followed by centrifugation enhanced oil recovery: butanol addition allowed almost complete phase separation of the emulsion while ethanol addition resulted in 84% of oil recovery. Implementation of this method, however, would require additional steps for solvent separation. Addition of charged magnetic nanoparticles was effective by interacting electrostatically with the interface, resulting in emulsion destabilization under a magnetic field. This method reached almost 96% of oil recovery and it was potentially advantageous since no additional steps might be necessary for further purifying the recovered oil. PMID:25791419

  3. Phytosterol colloidal particles as Pickering stabilizers for emulsions.

    PubMed

    Liu, Fu; Tang, Chuan-He

    2014-06-01

    Water-insoluble phytosterols were developed into a kind of colloidal particle as Pickering stabilizers for emulsions by a classic anti-solvent method using 100% ethanol as the organic phase to solubilize the phytosterols and whey protein concentrate (WPC) as the emulsifier. The colloidal particles in the dispersion, with morphology of stacked platelet-like sheets, had a mean diameter of 44.7 and 24.7 μm for the volume- and surface-averaged sizes, respectively. The properties and stability of the emulsions stabilized by these colloidal particles were highly dependent upon the applied total solid concentration (c; in the dispersion) and oil fraction (ø). The results indicated that (1) at a low c value (<1.0%, w/v) the emulsions were susceptible to phase separation, even at a low ø of 0.2, (2) at low ø values (e.g., 0.2 or 0.3) and a relatively high c value (1.0%, w/v, or above), a severe droplet flocculation occurred for the emulsions, and (3) when both c and ø were appropriately high, a kind of self-supporting gel-like emulsions could be formed. More interestingly, a phase inversion of the emulsions from the oil-in-water to water-in-oil type was observed, upon the ø increasing from 0.2 to 0.6 (especially at high c values, e.g., 3.0%, w/v). The elaborated Pickering emulsions stabilized by the phytosterol colloidal particles with a gel-like behavior would provide a candidate to act as a novel delivery system for active ingredients.

  4. To Model Chemical Reactivity in Heterogeneous Emulsions, Think Homogeneous Microemulsions.

    PubMed

    Bravo-Díaz, Carlos; Romsted, Laurence Stuart; Liu, Changyao; Losada-Barreiro, Sonia; Pastoriza-Gallego, Maria José; Gao, Xiang; Gu, Qing; Krishnan, Gunaseelan; Sánchez-Paz, Verónica; Zhang, Yongliang; Dar, Aijaz Ahmad

    2015-08-25

    Two important and unsolved problems in the food industry and also fundamental questions in colloid chemistry are how to measure molecular distributions, especially antioxidants (AOs), and how to model chemical reactivity, including AO efficiency in opaque emulsions. The key to understanding reactivity in organized surfactant media is that reaction mechanisms are consistent with a discrete structures-separate continuous regions duality. Aggregate structures in emulsions are determined by highly cooperative but weak organizing forces that allow reactants to diffuse at rates approaching their diffusion-controlled limit. Reactant distributions for slow thermal bimolecular reactions are in dynamic equilibrium, and their distributions are proportional to their relative solubilities in the oil, interfacial, and aqueous regions. Our chemical kinetic method is grounded in thermodynamics and combines a pseudophase model with methods for monitoring the reactions of AOs with a hydrophobic arenediazonium ion probe in opaque emulsions. We introduce (a) the logic and basic assumptions of the pseudophase model used to define the distributions of AOs among the oil, interfacial, and aqueous regions in microemulsions and emulsions and (b) the dye derivatization and linear sweep voltammetry methods for monitoring the rates of reaction in opaque emulsions. Our results show that this approach provides a unique, versatile, and robust method for obtaining quantitative estimates of AO partition coefficients or partition constants and distributions and interfacial rate constants in emulsions. The examples provided illustrate the effects of various emulsion properties on AO distributions such as oil hydrophobicity, emulsifier structure and HLB, temperature, droplet size, surfactant charge, and acidity on reactant distributions. Finally, we show that the chemical kinetic method provides a natural explanation for the cut-off effect, a maximum followed by a sharp reduction in AO efficiency with

  5. Dynamically reconfigurable complex emulsions via tunable interfacial tensions

    NASA Astrophysics Data System (ADS)

    Zarzar, Lauren D.; Sresht, Vishnu; Sletten, Ellen M.; Kalow, Julia A.; Blankschtein, Daniel; Swager, Timothy M.

    2015-02-01

    Emulsification is a powerful, well-known technique for mixing and dispersing immiscible components within a continuous liquid phase. Consequently, emulsions are central components of medicine, food and performance materials. Complex emulsions, including Janus droplets (that is, droplets with faces of differing chemistries) and multiple emulsions, are of increasing importance in pharmaceuticals and medical diagnostics, in the fabrication of microparticles and capsules for food, in chemical separations, in cosmetics, and in dynamic optics. Because complex emulsion properties and functions are related to the droplet geometry and composition, the development of rapid, simple fabrication approaches allowing precise control over the droplets' physical and chemical characteristics is critical. Significant advances in the fabrication of complex emulsions have been made using a number of procedures, ranging from large-scale, less precise techniques that give compositional heterogeneity using high-shear mixers and membranes, to small-volume but more precise microfluidic methods. However, such approaches have yet to create droplet morphologies that can be controllably altered after emulsification. Reconfigurable complex liquids potentially have great utility as dynamically tunable materials. Here we describe an approach to the one-step fabrication of three- and four-phase complex emulsions with highly controllable and reconfigurable morphologies. The fabrication makes use of the temperature-sensitive miscibility of hydrocarbon, silicone and fluorocarbon liquids, and is applied to both the microfluidic and the scalable batch production of complex droplets. We demonstrate that droplet geometries can be alternated between encapsulated and Janus configurations by varying the interfacial tensions using hydrocarbon and fluorinated surfactants including stimuli-responsive and cleavable surfactants. This yields a generalizable strategy for the fabrication of multiphase emulsions with

  6. Cholesterol improves the utilization of parenteral lipid emulsions.

    PubMed

    Druml, Wilfred; Fischer, Margot

    2003-11-28

    Lipid emulsions have become an indispensable component of parenteral nutrition. Commercially available emulsions mostly have an identical composition of triglycerides (from plant oils) and egg-yolk phospholipids as emulsifier. Previous attempts to improve the composition of lipid emulsions have focused mainly on the triglyceride moiety. In the first fundamental modification of a lipid emulsion since their broader introduction into clinical medicine, we included free cholesterol in a lipid emulsion. We evaluated elimination and hydrolysis of triglycerides and lipid oxidation (by indirect calorimetry) in 10 healthy male normolipemic volunteers, comparing a conventional lipid emulsion (20% triglycerides) with an otherwise identical emulsion with the addition of 4 g/l free cholesterol. The rise in plasma triglycerides was mitigated during infusion of the cholesterol-enriched solution (323.8 +/- 27.5 vs. 202.0 +/- 18.9 mg.dL-1, p < 0.001), plasma half-life was reduced (41.6 +/- 5.4 vs. 29.3 +/- 5.1 min, p < 0.05), and total-body clearance was enhanced (0.96 +/- 0.1 vs. 1.52 +/- 0.2 ml.b.w.(.)min-1, p < 0.02). The rise in plasma free fatty acids (400.7 +/- 39.0 vs. 532.2 +/- 64.0 mumol.L-1; p < 0.02) and ketone bodies (beta-hydroxybutyrate) (151.6 +/- 37.0 vs. 226.3 +/- 33.01 mumol.L-1; p < 0.02) was augmented. Increases in plasma insulin and glucagon were less pronounced (p < 0.05). The fall in respiratory quotient was greater and the fraction of lipid oxidation as a percentage of total energy expenditure was increased (66.2% +/- 6.0 vs. 70.9% +/- 6.3, p < 0.05) during infusion of the modified solution. No impairment of gas exchange or other side effects were observed. Taken together these results indicate that the elimination of a cholesterol-supplemented lipid emulsion is accelerated, triglyceride hydrolysis is enhanced, and lipid oxidation is augmented. Thus, addition of cholesterol to a lipid emulsion might not only present a means of providing cholesterol in

  7. Treatment methods for breaking certain oil and water emulsions

    DOEpatents

    Sealock, Jr., L. John; Baker, Eddie G.; Elliott, Douglas C.

    1992-01-01

    Disclosed are treatment methods for breaking emulsions of petroleum oil and salt water, fatty oil and water, and those resulting from liquefication of organic material. The emulsions are broken by heating to a predetermined temperature at or above about 200.degree. C. and pressurizing to a predetermined pressure above the vapor pressure of water at the predetermined temperature to produce a heated and pressurized fluid. The heated and pressurized fluid is contained in a single vessel at the predetermined temperature and pressure for a predetermined period of time to effectively separate the emulsion into substantially distinct first and second phases, the first phase comprising primarily the petroleum oil, the second phase comprising primarily the water. The first and second phases are separately withdrawn from the vessel at a withdraw temperature between about 200.degree. C. and 374.degree. C. and a withdraw pressure above the vapor pressure of water at the withdraw temperature. Where solids are present in the certain emulsions, the above described treatment may also effectively separate the certain emulsion into a substantially distinct third phase comprising primarily the solids.

  8. Investigation of different emulsion systems for dermal delivery of nicotinamide.

    PubMed

    Tuncay, Sakine; Özer, Özgen

    2013-01-01

    Nicotinamide (NA) has been shown to have beneficial effects on several skin diseases such as tumor, acne vulgaris, photodamage, cellulite and atopic dermatitis. The purpose of this study was to develop a multiple emulsion and a microemulsion formulation as delivery systems for NA. A two-step process was used to prepare the W/O/W multiple emulsion. Optimum microemulsion formulation was selected by using construction of pseudo-ternary phase diagram. The physicochemical properties such as droplet size and viscosity measurements, stability studies were also evaluated. Ex-vivo permeation studies were performed with Franz-type diffusion cells and the samples were analysed by high performance liquid chromatography (HPLC). The permeation data showed that there was no significant difference between multiple emulsion and microemulsion (p > 0.05). Transepidermal water loss (TEWL) was also measured. As a result of TEWL studies, a slight increase of TEWL values was observed for microemulsion formulation on rat skin when compared with multiple emulsion and commercial formulation. The results suggested that microemulsion and multiple emulsion formulations could be new and alternative dosage forms for topical application of NA.

  9. Rejuvenation of Spent Media via Supported Emulsion Liquid Membranes

    NASA Technical Reports Server (NTRS)

    Wiencek, John M.

    2002-01-01

    The overall goal of this project is to maximize the reuseability of spent fermentation media. Supported emulsion liquid membrane separation, a highly efficient extraction technique, is used to remove inhibitory byproducts during fermentation; thus, improving the yield while reducing the need for fresh water. The key objectives of this study are: Develop an emulsion liquid membrane system targeting low molecular weight organic acids which has minimal toxicity on a variety of microbial systems; Conduct mass transfer studies to allow proper modeling and design of a supported emulsion liquid membrane system; Investigate the effect of gravity on emulsion coalescence within the membrane unit; Access the effect of water re-use on fermentation yields in a model microbial system; Develop a perfusion-type fermentor utilizing a supported emulsion liquid membrane system to control inhibitory fermentation byproducts; Work for the coming year will focus on the determination of toxicity of various solvents, selection of the emulsifying agents, as well as characterizing the mass transfer of hollow-fiber contactors.

  10. Multiwalled Carbon Nanotubes at the Interface of Pickering Emulsions.

    PubMed

    Briggs, Nicholas M; Weston, Javen S; Li, Brian; Venkataramani, Deepika; Aichele, Clint P; Harwell, Jeffrey H; Crossley, Steven P

    2015-12-01

    Carbon nanotubes exhibit very unique properties in biphasic systems. Their interparticle attraction leads to reduced droplet coalescence rates and corresponding improvements in emulsion stability. Here we use covalent and noncovalent techniques to modify the hydrophilicity of multiwalled carbon nanotubes (MWCNTs) and study their resulting behavior at an oil-water interface. By using both paraffin wax/water and dodecane/water systems, the thickness of the layer of MWNTs at the interface and resulting emulsion stability are shown to vary significantly with the approach used to modify the MWNTs. Increased hydrophilicity of the MWNTs shifts the emulsions from water-in-oil to oil-in-water. The stability of the emulsion is found to correlate with the thickness of nanotubes populating the oil-water interface and relative strength of the carbon nanotube network. The addition of a surfactant decreases the thickness of nanotubes at the interface and enhances the overall interfacial area stabilized at the expense of increased droplet coalescence rates. To the best of our knowledge, this is the first time the interfacial thickness of modified carbon nanotubes has been quantified and correlated to emulsion stability.

  11. Double emulsion formation through hierarchical flow-focusing microchannel

    NASA Astrophysics Data System (ADS)

    Azarmanesh, Milad; Farhadi, Mousa; Azizian, Pooya

    2016-03-01

    A microfluidic device is presented for creating double emulsions, controlling their sizes and also manipulating encapsulation processes. As a result of three immiscible liquids' interaction using dripping instability, double emulsions can be produced elegantly. Effects of dimensionless numbers are investigated which are Weber number of the inner phase (Wein), Capillary number of the inner droplet (Cain), and Capillary number of the outer droplet (Caout). They affect the formation process, inner and outer droplet size, and separation frequency. Direct numerical simulation of governing equations was done using volume of fluid method and adaptive mesh refinement technique. Two kinds of double emulsion formation, the two-step and the one-step, were simulated in which the thickness of the sheath of double emulsions can be adjusted. Altering each dimensionless number will change detachment location, outer droplet size and droplet formation period. Moreover, the decussate regime of the double-emulsion/empty-droplet is observed in low Wein. This phenomenon can be obtained by adjusting the Wein in which the maximum size of the sheath is discovered. Also, the results show that Cain has significant influence on the outer droplet size in the two-step process, while Caout affects the sheath in the one-step formation considerably.

  12. 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.

  13. Size analysis of nanoparticles extracted from W/O emulsions.

    PubMed

    Nagelreiter, C; Kotisch, H; Heuser, T; Valenta, C

    2015-07-01

    Nanosized particles are frequently used in many different applications, especially TiO2 nanoparticles as physical filters in sunscreens to protect the skin from UV radiation. However, concerns have arisen about possible health issues caused by nanoparticles and therefore, the assessment of the occurrence of nanoparticles is important in pharmaceutical and cosmetic formulations. In a previous work of our group, a method was presented to extract nanoparticles from O/W emulsions. But to respond to the needs of dry and sensitive skin, sunscreens of the water-in-oil emulsion type are available. In these, assessment of present nanoparticles is also an important issue, so the present study offers a method for extracting nanoparticles from W/O emulsions. Both methods emanate from the same starting point, which minimizes both effort and cost before the beginning of the assessment. By addition of NaOH pellets and centrifugation, particles were extracted from W/O emulsions and measured for their size and surface area by laser diffraction. With the simple equation Q=A/S a distinction between nanoparticles and microparticles was achieved in W/O emulsions, even in commercially available samples. The present method is quick and easy to implement, which makes it cost-effective. PMID:25907509

  14. Multiwalled Carbon Nanotubes at the Interface of Pickering Emulsions.

    PubMed

    Briggs, Nicholas M; Weston, Javen S; Li, Brian; Venkataramani, Deepika; Aichele, Clint P; Harwell, Jeffrey H; Crossley, Steven P

    2015-12-01

    Carbon nanotubes exhibit very unique properties in biphasic systems. Their interparticle attraction leads to reduced droplet coalescence rates and corresponding improvements in emulsion stability. Here we use covalent and noncovalent techniques to modify the hydrophilicity of multiwalled carbon nanotubes (MWCNTs) and study their resulting behavior at an oil-water interface. By using both paraffin wax/water and dodecane/water systems, the thickness of the layer of MWNTs at the interface and resulting emulsion stability are shown to vary significantly with the approach used to modify the MWNTs. Increased hydrophilicity of the MWNTs shifts the emulsions from water-in-oil to oil-in-water. The stability of the emulsion is found to correlate with the thickness of nanotubes populating the oil-water interface and relative strength of the carbon nanotube network. The addition of a surfactant decreases the thickness of nanotubes at the interface and enhances the overall interfacial area stabilized at the expense of increased droplet coalescence rates. To the best of our knowledge, this is the first time the interfacial thickness of modified carbon nanotubes has been quantified and correlated to emulsion stability. PMID:26549532

  15. Engineering of acidic O/W emulsions with pectin.

    PubMed

    Alba, K; Sagis, L M C; Kontogiorgos, V

    2016-09-01

    Pectins with distinct molecular design were isolated by aqueous extraction at pH 2.0 or 6.0 and were examined in terms of their formation and stabilisation capacity of model n-alkane-in-water emulsions at acidic pH (pH 2.0). The properties and stability of the resulting emulsions were examined by means of droplet size distribution analysis, Lifshitz-Slyozov-Wagner modelling, bulk rheology, interfacial composition analysis, large-amplitude oscillatory surface dilatational rheology, electrokinetic analysis and fluorescence microscopy. Both pectin preparations were able to emulsify alkanes in water but exhibited distinct ageing characteristics. Emulsions prepared using pectin isolated at pH 6.0 were remarkably stable with respect to droplet growth after thirty days of ageing, while those prepared with pectin isolated at pH 2.0 destabilised rapidly. Examination of chemical composition of interfacial layers indicated multi-layered adsorption of pectins at the oil-water interface. The higher long-term stability of emulsions prepared with pectin isolated at high pH is attributed to mechanically stronger interfaces, the highly branched nature and the low hydrodynamic volume of the chains that result in effective steric stabilisation whereas acetyl and methyl contents do not contribute to the long-term stability. The present work shows that it is possible by tailoring the fine structure of pectin to engineer emulsions that operate in acidic environments.

  16. Thermodynamically Stable Pickering Emulsions Stabilized by Janus Dumbbells

    NASA Astrophysics Data System (ADS)

    Tu, Fuquan; Park, Bum Jun; Lee, Daeyeon

    2013-03-01

    Janus particles have two sides with different, often opposite, surface properties. Janus dumbbell is one type of Janus particles that consists of two partially fused spherical lobes. It is possible to independently control the geometry and surface wettability of Janus dumbbells. Janus dumbbells can also be produced in a large quantity, making them useful for practical applications such as emulsion stabilization. In this work, we calculate the free energy of emulsion formation using amphiphilic Janus dumbbells as solid surfactants. In contrast to kinetically stable emulsions stabilized by homogeneous particles, emulsion stabilized by Janus dumbbells can be thermodynamically stable. There also exists an optimal radius of droplets that can be stabilized by infinite or limited number of amphiphilic dumbbells in the continuous phase. We demonstrate that the optimal radius of dumbbell-stabilized droplets can be predicted based on the volume of the dispersed phase and the volume fraction of dumbbells in the continuous phase. We believe our calculation will provide guidelines for using Janus dumbbells as colloid surfactants to generate stable emulsions.

  17. Preparation of double Pickering emulsions stabilized by chemically tailored nanocelluloses.

    PubMed

    Cunha, Ana G; Mougel, Jean-Bruno; Cathala, Bernard; Berglund, Lars A; Capron, Isabelle

    2014-08-12

    Nanocelluloses are bio-based nanoparticles of interest as stabilizers for oil-in-water (o/w) Pickering emulsions. In this work, the surface chemistry of nanocelluloses of different length, nanofibrillated cellulose (NFC, long) and cellulose nanocrystals (CNC, short), was successfully tailored by chemical modification with lauroyl chloride (C12). The resulting nanofibers were less hydrophilic than the original and able to stabilize water-in-oil (w/o) emulsions. The combination of the two types of nanocelluloses (C12-modified and native) led to new surfactant-free oil-in-water-in-oil (o/w/o) double emulsions stabilized by nanocellulose at both interfaces. Characterization was performed with respect to droplet size distribution, droplet stability over time, and stability after centrifugation. Nanocellulose-based Pickering emulsions can be designed with a substantial degree of control, as demonstrated by the stability of the chemically tailored NFC double emulsions. Furthermore, it was demonstrated that increased nanofiber length leads to increased stability.

  18. Induced phase transitions of nanoparticle-stabilized emulsions

    NASA Astrophysics Data System (ADS)

    Frijters, Stefan; Günther, Florian; Harting, Jens

    2013-11-01

    Nanoparticles can stabilize fluid-fluid interfaces over long timescales and are nowadays commonly used, e.g. in emulsions. However, their fundamental properties are as of yet poorly understood. Nanoparticle-stabilized emulsions can exhibit different phases, such as Pickering emulsions or bijels, which can be characterized by their different topologies and rheology. We investigate the effect of various initial conditions on random mixtures of two fluids and nanoparticles - in particular, the final state these systems will reach. For this, we use the well-established 3D lattice Boltzmann method, extended to allow for the added nanoparticles. After the evolution of the emulsions has stopped, we induce transitions from one state to another by gradually changing the wettability of the nanoparticles over time. This changes the preferential local curvature of the interfaces, which strongly affects the global state. We observe strong hysteresis effects because of the energy barrier presented by the necessary massive reordering of the particles. Being able to change emulsion states in situ has potential application possibilities in filtering technology, or creating particle scaffolds.

  19. Diminution of phagocytosed perfluorocarbon emulsions using perfluoroalkylated polyethylene glycol surfactant.

    PubMed

    Hsu, Y C; Peng, C A

    2001-05-18

    Perfluorocarbon emulsions have been considered as potential blood substitutes for years due to their high capacity of dissolving respiratory oxygen and carbon dioxide. However, they have been reported to associate with side effects (e.g., flu-like syndrome) after being injected into animal's bloodstream. The cause of these side effects is related to the phagocytosis of perfluorocarbon emulsions by cells (e.g., macrophages). Inspired by the approach of using polyethylene glycol (PEG) to camouflage liposomes, we synthesized a perfluoroalkylated PEG (R(F)-PEG) surfactant to provide steric hindrance for decreasing phagocytosis of perfluorocarbon emulsions. The R(F)-PEG surfactant along with Pluronic F-68 and egg yolk phospholipid mediated perfluorocarbon emulsions were incubated individually with J774A.1 macrophages to examine the degree of phagocytosis. 19F NMR studies were used to quantitatively determine the amount of perfluorocarbon emulsions phagocytosed by macrophages. Results showed that the degree of phagocytosis was diminished to a large extent for perfluorocarbon microparticles emulsified by the R(F)-PEG surfactant. PMID:11350051

  20. Fluoroalkylated polyethylene glycol as potential surfactant for perfluorocarbon emulsion.

    PubMed

    Peng, C A; Hsu, Y C

    2001-11-01

    So far, perfluorocarbon (PFC) emulsions have been manufactured based mainly on two surfactants, Pluronic F-68 and egg yolk phospholipids (EYP) for clinical use. However, they have been documented to induce inflammatory or allergic responses when PFC emulsions were injected into human bloodstream. The cause of these side effects is associated with the phagocytosis of emulsified PFC microparticles by cells such as macrophages. In order to lessen the side effects, it is logic to develop surfactants, which are more phagocytosis-resistant and biocompatible. In this study, a perfluoroalkylated polyethylene glycol (R(F)-PEG) surfactant was synthesized by reacting perfluorooctanoyl chloride (C7F15COCl) with PEG of molecular weigh 8000. Both R(F)-PEG 8000 and EYP were used to make PFC emulsions separately by an ultrasonic homogenizer. Individual PFC emulsions were then incubated with mouse macrophage J774A.1 cells to examine the degree of phagocytosis. From microscopic observation of cell morphology, our results showed that the process of phagocytosis was retarded to a large extend using the R(F)-PEG surfactant. We also harnessed 19F-NMR to quantitatively detect the amount of PFC emulsions phagocytosed by J774A.1 cells. 19F-NMR result was consistent with the qualitative microscopic observation aforementioned. PMID:11795633

  1. [What lipid emulsion should be administered to ICU patients?].

    PubMed

    Kreymann, G

    2014-01-01

    The review deals with a question what lipid emulsion should be administered to ICU patients according to recently published official parenteral and enteral nutrition guidelines. Classic lipid emulsions based on omega-6 fatty acids are immunosuppressive and should not be used with ICU patients. The olive/soy emulsion is immunoneutral and can be used for most patients. Many ICU patients are in an inflammatory state (e.g. sepsis, ARDS, pancreatitis). A common belief is that this "hyperinflammed patient population" would profit from an anti-inflammatory lipid component of their parenteral nutrition solution, such as fish oil. On the other hand, every anti-inflammatory therapy has the disadvantage of also being immunosuppressive. Inflammation is a necessary part of the host defense against infection and any correct anti-inflammatory medication presupposes the exact immunologic knowledge that there is too much inflammation for a given situation. This "too much" is certainly not fulfilled in every patient with sepsis, ARDS or pancreatitis. At the bedside it is nearly impossible to determine the degree of "hyper" inflammation. In reality, a number of these patients may be adequately inflamed or, in fact, even hypoinflammed. Specific emulsions which can be used in hyper- or hypoinflammation should be developed in the future. As long as these difficulties in the immunologic diagnosis prevail, the clinician might be best advised to use an immunoneutral lipid emulsion when choosing a lipid preparation for the ICU patients. PMID:25306684

  2. 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. PMID:27305061

  3. Size analysis of nanoparticles extracted from W/O emulsions.

    PubMed

    Nagelreiter, C; Kotisch, H; Heuser, T; Valenta, C

    2015-07-01

    Nanosized particles are frequently used in many different applications, especially TiO2 nanoparticles as physical filters in sunscreens to protect the skin from UV radiation. However, concerns have arisen about possible health issues caused by nanoparticles and therefore, the assessment of the occurrence of nanoparticles is important in pharmaceutical and cosmetic formulations. In a previous work of our group, a method was presented to extract nanoparticles from O/W emulsions. But to respond to the needs of dry and sensitive skin, sunscreens of the water-in-oil emulsion type are available. In these, assessment of present nanoparticles is also an important issue, so the present study offers a method for extracting nanoparticles from W/O emulsions. Both methods emanate from the same starting point, which minimizes both effort and cost before the beginning of the assessment. By addition of NaOH pellets and centrifugation, particles were extracted from W/O emulsions and measured for their size and surface area by laser diffraction. With the simple equation Q=A/S a distinction between nanoparticles and microparticles was achieved in W/O emulsions, even in commercially available samples. The present method is quick and easy to implement, which makes it cost-effective.

  4. Comparative biomechanical and radiological characterization of osseointegration of a biodegradable magnesium alloy pin and a copolymeric control for osteosynthesis.

    PubMed

    Lindtner, Richard A; Castellani, Christoph; Tangl, Stefan; Zanoni, Gerald; Hausbrandt, Peter; Tschegg, Elmar K; Stanzl-Tschegg, Stefanie E; Weinberg, Annelie-Martina

    2013-12-01

    Magnesium alloys offer great advantages as degradable implant material for pediatric fracture fixation and hold the potential to overcome certain critical shortcomings inherent to currently used degradable (co)polymers. Besides good biocompatibility and appropriate degradation kinetics, sufficient implant anchorage in host bone is critical to prevent implant failure. Bone-implant anchorage of biodegradable magnesium alloys, however, has not yet been related and compared to that of copolymers, their degradable counterparts currently in clinical use. The aim of this study, therefore, was to comparatively assess bone-implant interface strength and the amount of peri-implant bone of a biodegradable magnesium alloy pin (Mg-Y-Nd-HRE) and a self-reinforced copolymeric control (85/15 poly(l-lactic-co-glycolic acid)). To this purpose, push-out testing, microfocus computed tomography (μCT), histological and scanning electron microscopic examination was performed after 4, 12 and 24 weeks of transcortical implantation in 72 rats. Biomechanical testing revealed significantly higher ultimate shear strength for the magnesium alloy pins than for the copolymeric controls at all 3 timepoints (P≤0.001 for all comparisons). As evaluated by μCT, the amount of bone present near the interface and in a wider radius (up to 0.5mm) around it was higher in the magnesium alloy implants at 4 weeks, without significant differences at 12 and 24 weeks. Histological examination confirmed direct bone-to-implant contact for both implant types. In vivo degradation of implants did not induce any noticeable local or systemic inflammation. This data suggests that the investigated degradable magnesium alloy rod exhibits markedly superior bone-implant interface strength and a greater amount of peri-implant bone than a self-reinforced copolymeric control currently in use; thus it fulfills a crucial prerequisite for its successful clinical deployment as an alternative degradable orthopedic implant

  5. Rapid enumeration of phage in monodisperse emulsions.

    PubMed

    Tjhung, Katrina F; Burnham, Sean; Anany, Hany; Griffiths, Mansel W; Derda, Ratmir

    2014-06-17

    Phage-based detection assays have been developed for the detection of viable bacteria for applications in clinical diagnosis, monitoring of water quality, and food safety. The majority of these assays deliver a positive readout in the form of newly generated progeny phages by the bacterial host of interest. Progeny phages are often visualized as plaques, or holes, in a lawn of bacteria on an agar-filled Petri dish; however, this rate-limiting step requires up to 12 h of incubation time. We have previously described an amplification of bacteriophages M13 inside droplets of media suspended in perfluorinated oil; a single phage M13 in a droplet yields 10(7) copies in 3-4 h. Here, we describe that encapsulation of reporter phages, both lytic T4-LacZ and nonlytic M13, in monodisperse droplets can also be used for rapid enumeration of phage. Compartmentalization in droplets accelerated the development of the signal from the reporter enzyme; counting of "positive" droplets yields accurate enumeration of phage particles ranging from 10(2) to 10(6) pfu/mL. For enumeration of T4-LacZ phage, the fluorescent signal appeared in as little as 90 min. Unlike bulk assays, quantification in emulsion is robust and insensitive to fluctuations in environmental conditions (e.g., temperature). Power-free emulsification using gravity-driven flow in the absence of syringe pumps and portable fluorescence imaging solutions makes this technology promising for use at the point of care in low-resource environments. This droplet-based phage enumeration method could accelerate and simplify point-of-care detection of the pathogens for which reporter bacteriophages have been developed.

  6. Rapid enumeration of phage in monodisperse emulsions.

    PubMed

    Tjhung, Katrina F; Burnham, Sean; Anany, Hany; Griffiths, Mansel W; Derda, Ratmir

    2014-06-17

    Phage-based detection assays have been developed for the detection of viable bacteria for applications in clinical diagnosis, monitoring of water quality, and food safety. The majority of these assays deliver a positive readout in the form of newly generated progeny phages by the bacterial host of interest. Progeny phages are often visualized as plaques, or holes, in a lawn of bacteria on an agar-filled Petri dish; however, this rate-limiting step requires up to 12 h of incubation time. We have previously described an amplification of bacteriophages M13 inside droplets of media suspended in perfluorinated oil; a single phage M13 in a droplet yields 10(7) copies in 3-4 h. Here, we describe that encapsulation of reporter phages, both lytic T4-LacZ and nonlytic M13, in monodisperse droplets can also be used for rapid enumeration of phage. Compartmentalization in droplets accelerated the development of the signal from the reporter enzyme; counting of "positive" droplets yields accurate enumeration of phage particles ranging from 10(2) to 10(6) pfu/mL. For enumeration of T4-LacZ phage, the fluorescent signal appeared in as little as 90 min. Unlike bulk assays, quantification in emulsion is robust and insensitive to fluctuations in environmental conditions (e.g., temperature). Power-free emulsification using gravity-driven flow in the absence of syringe pumps and portable fluorescence imaging solutions makes this technology promising for use at the point of care in low-resource environments. This droplet-based phage enumeration method could accelerate and simplify point-of-care detection of the pathogens for which reporter bacteriophages have been developed. PMID:24892245

  7. Demulsification of emulsions produced from surfactant recovery operations and recovery of surfactants therefrom

    SciTech Connect

    Allison, J.B.; Kudchadker, M.V.; Whittington, L.E.

    1981-07-07

    Treatment of emulsions of oil and water produced from surfactant recovery operations whereby the produced emulsions containing surfactants are demulsified and the surfactants are recovered in the water phase.

  8. Use of oil-in-water emulsions to control fungal deterioration of strawberry jams.

    PubMed

    Ribes, Susana; Fuentes, Ana; Talens, Pau; Barat, José M

    2016-11-15

    This work aimed to control the fungal deterioration of strawberry jams. The antifungal activity of the clove, cinnamon leaf, lemon and mandarin essential oils and their effectiveness in oil-in-water emulsions were evaluated. According to the results obtained, only clove and cinnamon leaf oils were selected to prepare emulsions. All the tested emulsions were stable, independently the amount of polymer and essential oil used. Essential oil loss was affected by the amount of polymer employed to prepare the emulsions. The oil-in-water emulsions with 5.0mg/g xanthan gum, and with 0.55mg/g clove or 0.65mg/g cinnamon leaf essential oil, were used for the in vivo tests. The jams prepared with the oil-in-water emulsions showed a lower fungal decay compared with jams without emulsion. The present work demonstrated that emulsions can be employed to prevent strawberry jam mould spoilage.

  9. Use of oil-in-water emulsions to control fungal deterioration of strawberry jams.

    PubMed

    Ribes, Susana; Fuentes, Ana; Talens, Pau; Barat, José M

    2016-11-15

    This work aimed to control the fungal deterioration of strawberry jams. The antifungal activity of the clove, cinnamon leaf, lemon and mandarin essential oils and their effectiveness in oil-in-water emulsions were evaluated. According to the results obtained, only clove and cinnamon leaf oils were selected to prepare emulsions. All the tested emulsions were stable, independently the amount of polymer and essential oil used. Essential oil loss was affected by the amount of polymer employed to prepare the emulsions. The oil-in-water emulsions with 5.0mg/g xanthan gum, and with 0.55mg/g clove or 0.65mg/g cinnamon leaf essential oil, were used for the in vivo tests. The jams prepared with the oil-in-water emulsions showed a lower fungal decay compared with jams without emulsion. The present work demonstrated that emulsions can be employed to prevent strawberry jam mould spoilage. PMID:27283611

  10. Nonlinear Dynamic Characteristics of Oil-in-Water Emulsions

    NASA Astrophysics Data System (ADS)

    Yin, Zhaoqi; Han, Yunfeng; Ren, Yingyu; Yang, Qiuyi; Jin, Ningde

    2016-08-01

    In this article, the nonlinear dynamic characteristics of oil-in-water emulsions under the addition of surfactant were experimentally investigated. Firstly, based on the vertical upward oil-water two-phase flow experiment in 20 mm inner diameter (ID) testing pipe, dynamic response signals of oil-in-water emulsions were recorded using vertical multiple electrode array (VMEA) sensor. Afterwards, the recurrence plot (RP) algorithm and multi-scale weighted complexity entropy causality plane (MS-WCECP) were employed to analyse the nonlinear characteristics of the signals. The results show that the certainty is decreasing and the randomness is increasing with the increment of surfactant concentration. This article provides a novel method for revealing the nonlinear dynamic characteristics, complexity, and randomness of oil-in-water emulsions with experimental measurement signals.

  11. Synthesis of Fluorosurfactants for Emulsion-Based Biological Applications

    PubMed Central

    2015-01-01

    Microemulsion represents an attractive platform for fundamental and applied biomedical research because the emulsified droplets can serve as millions of compartmentalized micrometer-sized reactors amenable to high-throughput screening or online monitoring. However, establishing stable emulsions with surfactants that are compatible with biological applications remains a significant challenge. Motivated by the lack of commercially available surfactants suitable for microemulsion-based biological assays, this study describes the facile synthesis of a biocompatible fluorosurfactant with nonionic tris(hydroxymethyl)methyl (Tris) polar head groups. We have further demonstrated compatibility of the developed surfactant with diverse emulsion-based applications, including DNA polymeric nanoparticle synthesis, enzymatic activity assay, and bacterial or mammalian cell culture, in the setup of both double- and multiphases of emulsions. PMID:24646088

  12. High speed automated microtomography of nuclear emulsions and recent application

    SciTech Connect

    Tioukov, V.; Aleksandrov, A.; Consiglio, L.; De Lellis, G.; Vladymyrov, M.

    2015-12-31

    The development of high-speed automatic scanning systems was the key-factor for massive and successful emulsions application for big neutrino experiments like OPERA. The emulsion detector simplicity, the unprecedented sub-micron spatial resolution and the unique ability to provide intrinsically 3-dimensional spatial information make it a perfect device for short-living particles study, where the event topology should be precisely reconstructed in a 10-100 um scale vertex region. Recently the exceptional technological progress in image processing and automation together with intensive R&D done by Italian and Japanese microscopy groups permit to increase the scanning speed to unbelievable few years ago m{sup 2}/day scale and so greatly extend the range of the possible applications for emulsion-based detectors to other fields like: medical imaging, directional dark matter search, nuclear physics, geological and industrial applications.

  13. Automated Track Recognition and Event Reconstruction in Nuclear Emulsion

    NASA Technical Reports Server (NTRS)

    Deines-Jones, P.; Cherry, M. L.; Dabrowska, A.; Holynski, R.; Jones, W. V.; Kolganova, E. D.; Kudzia, D.; Nilsen, B. S.; Olszewski, A.; Pozharova, E. A.; Sengupta, K.; Szarska, M.; Trzupek, A.; Waddington, C, J.; Wefel, J. P.; Wilczynska, B.; Wilczynski, H.; Wolter, W.; Wosiek, B.; Wozniak, K.

    1998-01-01

    The major advantages of nuclear emulsion for detecting charged particles are its submicron position resolution and sensitivity to minimum ionizing particles. These must be balanced, however, against the difficult manual microscope measurement by skilled observers required for the analysis. We have developed an automated system to acquire and analyze the microscope images from emulsion chambers. Each emulsion plate is analyzed independently, allowing coincidence techniques to be used in order to reject back- ground and estimate error rates. The system has been used to analyze a sample of high-multiplicity Pb-Pb interactions (charged particle multiplicities approx. 1100) produced by the 158 GeV/c per nucleon Pb-208 beam at CERN. Automatically reconstructed track lists agree with our best manual measurements to 3%. We describe the image analysis and track reconstruction techniques, and discuss the measurement and reconstruction uncertainties.

  14. High speed automated microtomography of nuclear emulsions and recent application

    NASA Astrophysics Data System (ADS)

    Tioukov, V.; Aleksandrov, A.; Consiglio, L.; De Lellis, G.; Vladymyrov, M.

    2015-12-01

    The development of high-speed automatic scanning systems was the key-factor for massive and successful emulsions application for big neutrino experiments like OPERA. The emulsion detector simplicity, the unprecedented sub-micron spatial resolution and the unique ability to provide intrinsically 3-dimensional spatial information make it a perfect device for short-living particles study, where the event topology should be precisely reconstructed in a 10-100 um scale vertex region. Recently the exceptional technological progress in image processing and automation together with intensive R&D done by Italian and Japanese microscopy groups permit to increase the scanning speed to unbelievable few years ago m2/day scale and so greatly extend the range of the possible applications for emulsion-based detectors to other fields like: medical imaging, directional dark matter search, nuclear physics, geological and industrial applications.

  15. Monodisperse Emulsion Drop Microenvironments for Bacterial Biofilm Growth.

    PubMed

    Chang, Connie B; Wilking, James N; Kim, Shin-Hyun; Shum, Ho Cheung; Weitz, David A

    2015-08-26

    In this work, microfluidic technology is used to rapidly create hundreds of thousands of monodisperse double and triple emulsion drops that serve as 3D microenvironments for the containment and growth of bacterial biofilms. The size of these drops, with diameters from tens to hundreds of micrometers, makes them amenable to rapid manipulation and analysis. This is demonstrated by using microscopy to visualize cellular differentiation of Bacillus subtilis biofilm communities within each drop and the bacterial biofilm microstructure. Biofilm growth is explored upon specific interfaces in double and triple emulsions and upon negative and positive radii of curvature. Biofilm attachment of matrix and flagella mutants is studied as well as biofilms of Pseudomonas aeruginosa. This is the first demonstration of biofilms grown in microscale emulsion drops, which serve as both templates and containers for biofilm growth and attachment. These microenvironments have the potential to transform existing high-throughput screening methods for bacterial biofilms.

  16. Emulsion stability: delineation of different particle loss mechanisms

    SciTech Connect

    Reddy, S.R.; Fogler, H.S.

    1981-01-01

    The relative importance of Brownian flocculation and sedimentation flocculation was delineated. If the density difference between the particles and the continuous medium is approximately 0.22 g/cu cm, Brownian flocculation is significant for particles of diameter smaller than 1 micrometer and sedimentation flocculation for particles larger than 2 micrometers. A general map for any emulsion, depicting the regimes of dominant particle loss mechanism, was developed. From this map one can determine the qualitative information about the stability of an emulsion for a given particle size and density difference. The relative importance of Brownian flocculation and creaming was investigated. General maps were prepared showing the effect of various physical and electrochemical properties on the relative rates of flocculation and creaming. It is possible to obtain useful information on the stability of an emulsion before proceeding to complicated mathematical computations.

  17. Arrested of coalescence of emulsion droplets of arbitrary size

    NASA Astrophysics Data System (ADS)

    Mbanga, Badel L.; Burke, Christopher; Blair, Donald W.; Atherton, Timothy J.

    2013-03-01

    With applications ranging from food products to cosmetics via targeted drug delivery systems, structured anisotropic colloids provide an efficient way to control the structure, properties and functions of emulsions. When two fluid emulsion droplets are brought in contact, a reduction of the interfacial tension drives their coalescence into a larger droplet of the same total volume and reduced exposed area. This coalescence can be partially or totally hindered by the presence of nano or micron-size particles that coat the interface as in Pickering emulsions. We investigate numerically the dependance of the mechanical stability of these arrested shapes on the particles size, their shape anisotropy, their polydispersity, their interaction with the solvent, and the particle-particle interactions. We discuss structural shape changes that can be induced by tuning the particles interactions after arrest occurs, and provide design parameters for the relevant experiments.

  18. Manipulation of gel emulsions by variable microchannel geometry.

    PubMed

    Surenjav, Enkhtuul; Priest, Craig; Herminghaus, Stephan; Seemann, Ralf

    2009-01-21

    In this article we investigate the morphology and manipulation of monodisperse emulsions at high dispersed phase volume fractions (gel emulsions) in a microfluidic environment. Confined monodisperse gel emulsions self-organize into well-ordered droplet arrangements, which may be stable or metastable, depending on the geometry of the confining microchannel. Three arrangements are considered, in which the droplets are aligned in a single file, a two row, or a three row arrangement. We explore the potential for induced transitions between these distinct droplet arrangements as a tool for droplet-based microfluidic processing. Transitions are readily achieved by means of localized (geometrical) features in channel geometry, however the onset of the transition is strongly dependent on the subtleties of the microfluidic system, e.g. volume fraction, droplet size, and feature dimensions. The transitions can be achieved via fixed channel features or, when the continuous phase is a ferrofluid, by a virtual channel constriction created using a magnetic field. PMID:19107292

  19. Monodisperse Emulsion Drop Microenvironments for Bacterial Biofilm Growth.

    PubMed

    Chang, Connie B; Wilking, James N; Kim, Shin-Hyun; Shum, Ho Cheung; Weitz, David A

    2015-08-26

    In this work, microfluidic technology is used to rapidly create hundreds of thousands of monodisperse double and triple emulsion drops that serve as 3D microenvironments for the containment and growth of bacterial biofilms. The size of these drops, with diameters from tens to hundreds of micrometers, makes them amenable to rapid manipulation and analysis. This is demonstrated by using microscopy to visualize cellular differentiation of Bacillus subtilis biofilm communities within each drop and the bacterial biofilm microstructure. Biofilm growth is explored upon specific interfaces in double and triple emulsions and upon negative and positive radii of curvature. Biofilm attachment of matrix and flagella mutants is studied as well as biofilms of Pseudomonas aeruginosa. This is the first demonstration of biofilms grown in microscale emulsion drops, which serve as both templates and containers for biofilm growth and attachment. These microenvironments have the potential to transform existing high-throughput screening methods for bacterial biofilms. PMID:25959709

  20. Behavior of Malondialdehyde in Oil-in-Water Emulsions.

    PubMed

    Vandemoortele, Angelique; De Meulenaer, Bruno

    2015-06-17

    The impact of temperature, emulsifier, and protein type on the reactivity of malondialdehyde in oil-in-water emulsions was elucidated. Malondialdehyde recoveries in aqueous buffer, protein solutions, saturated oil, and fully hydrogenated coconut oil-in-water emulsions stabilized by whey proteins or Tween 20 at 4 or 40 °C were compared. At both temperatures, the reactivity of malondialdehyde in aqueous buffer was the same. In protein solutions, malondialdehyde concentrations were reduced further and its decrease was protein-dependent. Similar trends were found for emulsions. Surprisingly, malondialdehyde was very reactive in saturated oil because only 15% was recovered at 40 °C. However, the degradation in oil proved to be strongly temperature-dependent; at 4 °C, losses amounted to only 8%. This study revealed that malondialdehyde is a very reactive molecule, both in the presence and absence of proteins. Its use as a general oxidation marker should therefore be considered with care. PMID:26016781

  1. The jamming elasticity of emulsions stabilized by ionic surfactants.

    PubMed

    Scheffold, Frank; Wilking, James N; Haberko, Jakub; Cardinaux, Frédéric; Mason, Thomas G

    2014-07-28

    Oil-in-water emulsions composed of colloidal-scale droplets are often stabilized using ionic surfactants that provide a repulsive interaction between neighboring droplet interfaces, thereby inhibiting coalescence. If the droplet volume fraction is raised rapidly by applying an osmotic pressure, the droplets remain disordered, undergo an ergodic-nonergodic transition, and jam. If the applied osmotic pressure approaches the Laplace pressure of the droplets, then the jammed droplets also deform. Because solid friction and entanglements cannot play a role, as they might with solid particulate or microgel dispersions, the shear mechanical response of monodisperse emulsions can provide critical insight into the interplay of entropic, electrostatic, and interfacial forces. Here, we introduce a model that can be used to predict the plateau storage modulus and yield stress of a uniform charge-stabilized emulsion accurately if the droplet radius, interfacial tension, surface potential, Debye screening length, and droplet volume fraction are known. PMID:24913542

  2. Parenteral nutrition-associated liver disease and lipid emulsions.

    PubMed

    Zugasti Murillo, Ana; Petrina Jáuregui, Estrella; Elizondo Armendáriz, Javier

    2015-01-01

    Parenteral nutrition-associated liver disease (PNALD) is a particularly important problem in patients who need this type of nutritional support for a long time. Prevalence of the condition is highly variable depending on the series, and its clinical presentation is different in adults and children. The etiology of PNALD is not well defined, and participation of several factors at the same time has been suggested. When a bilirubin level >2 mg/dl is detected for a long time, other causes of liver disease should be ruled out and risk factors should be minimized. The composition of lipid emulsions used in parenteral nutrition is one of the factors related to PNALD. This article reviews the different types of lipid emulsions and the potential benefits of emulsions enriched with omega-3 fatty acids.

  3. Evaporation of Particle-Stabilized Emulsion Sunscreen Films.

    PubMed

    Binks, Bernard P; Fletcher, Paul D I; Johnson, Andrew J; Marinopoulos, Ioannis; Crowther, Jonathan M; Thompson, Michael A

    2016-08-24

    We recently showed (Binks et al., ACS Appl. Mater. Interfaces, 2016, DOI: 10.1021/acsami.6b02696) how evaporation of sunscreen films consisting of solutions of molecular UV filters leads to loss of UV light absorption and derived sun protection factor (SPF). In the present work, we investigate evaporation-induced effects for sunscreen films consisting of particle-stabilized emulsions containing a dissolved UV filter. The emulsions contained either droplets of propylene glycol (PG) in squalane (SQ), droplets of SQ in PG or droplets of decane in PG. In these different emulsion types, the SQ is involatile and shows no evaporation, the PG is volatile and evaporates relatively slowly, whereas the decane is relatively very volatile and evaporates quickly. We have measured the film mass and area, optical micrographs of the film structure, and the UV absorbance spectra during evaporation. For emulsion films containing the involatile SQ, evaporation of the PG causes collapse of the emulsion structure with some loss of specular UV absorbance due to light scattering. However, for these emulsions with droplets much larger than the wavelength of light, the light is scattered only at small forward angles so does not contribute to the diffuse absorbance and the film SPF. The UV filter remains soluble throughout the evaporation and thus the UV absorption by the filter and the SPF remain approximately constant. Both PG-in-SQ and SQ-in-PG films behave similarly and do not show area shrinkage by dewetting. In contrast, the decane-in-PG film shows rapid evaporative loss of the decane, followed by slower loss of the PG resulting in precipitation of the UV filter and film area shrinkage by dewetting which cause the UV absorbance and derived SPF to decrease. Measured UV spectra during evaporation are in reasonable agreement with spectra calculated using models discussed here. PMID:27482601

  4. Evaporation of Particle-Stabilized Emulsion Sunscreen Films.

    PubMed

    Binks, Bernard P; Fletcher, Paul D I; Johnson, Andrew J; Marinopoulos, Ioannis; Crowther, Jonathan M; Thompson, Michael A

    2016-08-24

    We recently showed (Binks et al., ACS Appl. Mater. Interfaces, 2016, DOI: 10.1021/acsami.6b02696) how evaporation of sunscreen films consisting of solutions of molecular UV filters leads to loss of UV light absorption and derived sun protection factor (SPF). In the present work, we investigate evaporation-induced effects for sunscreen films consisting of particle-stabilized emulsions containing a dissolved UV filter. The emulsions contained either droplets of propylene glycol (PG) in squalane (SQ), droplets of SQ in PG or droplets of decane in PG. In these different emulsion types, the SQ is involatile and shows no evaporation, the PG is volatile and evaporates relatively slowly, whereas the decane is relatively very volatile and evaporates quickly. We have measured the film mass and area, optical micrographs of the film structure, and the UV absorbance spectra during evaporation. For emulsion films containing the involatile SQ, evaporation of the PG causes collapse of the emulsion structure with some loss of specular UV absorbance due to light scattering. However, for these emulsions with droplets much larger than the wavelength of light, the light is scattered only at small forward angles so does not contribute to the diffuse absorbance and the film SPF. The UV filter remains soluble throughout the evaporation and thus the UV absorption by the filter and the SPF remain approximately constant. Both PG-in-SQ and SQ-in-PG films behave similarly and do not show area shrinkage by dewetting. In contrast, the decane-in-PG film shows rapid evaporative loss of the decane, followed by slower loss of the PG resulting in precipitation of the UV filter and film area shrinkage by dewetting which cause the UV absorbance and derived SPF to decrease. Measured UV spectra during evaporation are in reasonable agreement with spectra calculated using models discussed here.

  5. In situ UV-visible spectroelectrochemical studies on the copolymerization of diphenylamine with ortho-methoxy aniline

    NASA Astrophysics Data System (ADS)

    Santhosh, P.; Gopalan, A.; Vasudevan, T.

    2003-05-01

    UV-visible spectroelectrochemical studies on copolymerization of diphenylamine (DPA) with ortho-methoxy aniline (OMA) were carried out for different feed ratios of DPA and OMA using indium tin oxide (ITO)-coated glass as working electrode. The UV-visible spectra show clear dependencies on the molar feed composition of DPA or OMA used in electropolymerization. Derivative cyclic voltabsorptogram (DCVA) was deduced at the wavelengths corresponding to the absorption by the intermediate species and used to confirm the intermediates generated during the electropolymerization. The composition of DPA and OMA in the copolymer for the copolymers synthesized with different molar feed ratios of DPA and OMA was determined by UV-visible spectroscopy. Reactivity ratios of DPA and OMA were deduced by using Fineman-Ross and Kelen-Tudos methods and correlated with spectroelectrochemical results.

  6. Cytoskeleton mimetic reinforcement of a self-assembled N,N'-dialkylimidazolium ionic liquid monomer by copolymerization.

    SciTech Connect

    Grubjesic, S.; Seifert, S.; Firestone, M. A.; Materials Science Division

    2009-08-11

    Preparation and photopolymerization of a decylmethylimidazolium ionic liquid (IL) that possesses an acrylate counteranion are described. This IL monomer self-assembles upon addition of water and can be copolymerized with poly(ethylene glycol) diacrylate (PEGDA) in the presence of a photoinitiator, forming a mechanically durable material that adopts a lamellar structure with in-plane hexagonally ordered pores, as evidenced by small-angle X-ray scattering (SAXS). Thermogravimetric analysis, the extent of polymerization, and solubility-swelling studies indicate the formation of a network copolymer of the IL monomer and the PEGDA. Additional evidence for the formation of a nanostructured copolymer is provided by evaluating the product formed by replacement of the IL monomer with the nonpolymerizable analogue, decylmethylimidazolium chloride. The results demonstrate the possibility of designing a self-assembled amiphiphilic bilayer architecture that is reinforced by polymerization and cross-linking.

  7. Synthesis of α(1→4)-linked non-natural mannoglucans by α-glucan phosphorylase-catalyzed enzymatic copolymerization.

    PubMed

    Baba, Ryotaro; Yamamoto, Kazuya; Kadokawa, Jun-Ichi

    2016-10-20

    α-Glucan phosphorylase catalyzes enzymatic polymerization of α-d-glucose 1-phosphate (Glc-1-P) as a monomer from a maltooligosaccharide primer to produce α(1→4)-glucan, i.e., amylose, with liberating inorganic phosphate (Pi). Because of quite weak specificity for the recognition of substrates by thermostable α-glucan phosphorylase (from Aquifex aeolicus VF5), in this study, we investigated the enzymatic copolymerization of Glc-1-P with its analogue monomer, α-d-mannose 1-phosphate (Man-1-P) under the conditions for removal of Pi as the precipitate with ammonium and magnesium in ammonia buffer containing Mg(2+) ion to produce α(1→4)-linked non-natural mannoglucans composed of Glc/Man units. The reaction was conducted in different feed ratios using the maltotriose primer at 40°C for 7days. The MALDI-TOF mass and (1)H NMR spectra of the products fully supported the mannoglucan structures.

  8. 40 CFR 443.10 - Applicability; description of the asphalt emulsion subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... asphalt emulsion subcategory. 443.10 Section 443.10 Protection of Environment ENVIRONMENTAL PROTECTION... ROOFING MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Emulsion Subcategory § 443.10 Applicability; description of the asphalt emulsion subcategory. The provisions of this subpart are applicable...

  9. 40 CFR 443.10 - Applicability; description of the asphalt emulsion subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... asphalt emulsion subcategory. 443.10 Section 443.10 Protection of Environment ENVIRONMENTAL PROTECTION... ROOFING MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Emulsion Subcategory § 443.10 Applicability; description of the asphalt emulsion subcategory. The provisions of this subpart are applicable...

  10. 40 CFR 443.10 - Applicability; description of the asphalt emulsion subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... asphalt emulsion subcategory. 443.10 Section 443.10 Protection of Environment ENVIRONMENTAL PROTECTION... ROOFING MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Emulsion Subcategory § 443.10 Applicability; description of the asphalt emulsion subcategory. The provisions of this subpart are applicable...

  11. 40 CFR 443.10 - Applicability; description of the asphalt emulsion subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... asphalt emulsion subcategory. 443.10 Section 443.10 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Emulsion Subcategory § 443.10 Applicability; description of the asphalt emulsion subcategory. The provisions of this subpart are applicable to...

  12. 40 CFR 443.10 - Applicability; description of the asphalt emulsion subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... asphalt emulsion subcategory. 443.10 Section 443.10 Protection of Environment ENVIRONMENTAL PROTECTION... MATERIALS (TARS AND ASPHALT) POINT SOURCE CATEGORY Asphalt Emulsion Subcategory § 443.10 Applicability; description of the asphalt emulsion subcategory. The provisions of this subpart are applicable to...

  13. Development of a frozen yogurt fortified with a nano-emulsion containing purple rice bran oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of this study were to develop and evaluate a frozen yogurt (FY) fortified with a nano-emulsion containing purple rice bran oil (NPRBO). A nano-emulsion with a droplet size range of 150-300 nm was produced by sonication followed by ultra-shear homogenization. The nano-emulsion was mi...

  14. 40 CFR 428.20 - Applicability; description of the emulsion crumb rubber subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... emulsion crumb rubber subcategory. 428.20 Section 428.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Emulsion Crumb Rubber Subcategory § 428.20 Applicability; description of the emulsion crumb rubber...

  15. 40 CFR 428.20 - Applicability; description of the emulsion crumb rubber subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... emulsion crumb rubber subcategory. 428.20 Section 428.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Emulsion Crumb Rubber Subcategory § 428.20 Applicability; description of the emulsion crumb rubber...

  16. 40 CFR 428.20 - Applicability; description of the emulsion crumb rubber subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... emulsion crumb rubber subcategory. 428.20 Section 428.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Emulsion Crumb Rubber Subcategory § 428.20 Applicability; description of the emulsion crumb...

  17. 40 CFR 428.20 - Applicability; description of the emulsion crumb rubber subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... emulsion crumb rubber subcategory. 428.20 Section 428.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Emulsion Crumb Rubber Subcategory § 428.20 Applicability; description of the emulsion crumb...

  18. 40 CFR 428.20 - Applicability; description of the emulsion crumb rubber subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... emulsion crumb rubber subcategory. 428.20 Section 428.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Emulsion Crumb Rubber Subcategory § 428.20 Applicability; description of the emulsion crumb...

  19. 40 CFR 467.60 - Applicability; description of the drawing with emulsions or soaps subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... drawing with emulsions or soaps subcategory. 467.60 Section 467.60 Protection of Environment ENVIRONMENTAL... CATEGORY Drawing With Emulsions or Soaps Subcategory § 467.60 Applicability; description of the drawing with emulsions or soaps subcategory. This subpart applies to discharges of pollutants to waters of...

  20. 40 CFR 467.60 - Applicability; description of the drawing with emulsions or soaps subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... drawing with emulsions or soaps subcategory. 467.60 Section 467.60 Protection of Environment ENVIRONMENTAL... CATEGORY Drawing With Emulsions or Soaps Subcategory § 467.60 Applicability; description of the drawing with emulsions or soaps subcategory. This subpart applies to discharges of pollutants to waters of...

  1. 40 CFR 467.60 - Applicability; description of the drawing with emulsions or soaps subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... drawing with emulsions or soaps subcategory. 467.60 Section 467.60 Protection of Environment ENVIRONMENTAL... CATEGORY Drawing With Emulsions or Soaps Subcategory § 467.60 Applicability; description of the drawing with emulsions or soaps subcategory. This subpart applies to discharges of pollutants to waters of...

  2. 40 CFR 467.60 - Applicability; description of the drawing with emulsions or soaps subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... drawing with emulsions or soaps subcategory. 467.60 Section 467.60 Protection of Environment ENVIRONMENTAL... Drawing With Emulsions or Soaps Subcategory § 467.60 Applicability; description of the drawing with emulsions or soaps subcategory. This subpart applies to discharges of pollutants to waters of the...

  3. 40 CFR 467.60 - Applicability; description of the drawing with emulsions or soaps subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... drawing with emulsions or soaps subcategory. 467.60 Section 467.60 Protection of Environment ENVIRONMENTAL... Drawing With Emulsions or Soaps Subcategory § 467.60 Applicability; description of the drawing with emulsions or soaps subcategory. This subpart applies to discharges of pollutants to waters of the...

  4. Emulsions stability, from dilute to dense emulsions -- role of drops deformation.

    PubMed

    Sanfeld, Albert; Steinchen, Annie

    2008-07-01

    The present paper starts with a review of fundamental descriptions based on physico-chemical laws derived for emulsions with a special interest for eventual evidences of drops deformation. A critical analysis of theories and experiments is given that leads the authors to propose new static and dynamic models for the approach to flocculation and coalescence of two deformable drops in dense and dilute environments of other neighboring drops. The model developed is based on an old paper by Albers and Overbeek for W/O dense emulsions with non-deformable particles, that has been improved recently first by Sengupta and Papadopoulos and then by Mishchuk et al. to account for all the interaction forces (electrostatic, van der Waals and steric). The basic idea here rests in the assumption that the flat surface area of the two coalescing drops, interacting in the field of other particles, increases when the distance between the particles decreases according to an exponential law with a characteristic length related to the disjoining force in the inter-particle film and to the capillary pressure that opposes flattening. The difficulty lies, indeed, in manifold interpretations on experimental observations so that no clear conclusion can be derived on mechanisms responsible for the deformation of droplets. This is why, from a pure theoretical and physical point of view, according to rather complicated models, we propose a much more simple approach that permits to define a capillary length as part of virtual operations. In a static approach, this length is based on analogy with electricity, namely repulsion leads to flatness while attraction to hump. Therefore this brings us to a definition of a length depending on the maximum value of the disjoining pressure in competition with the capillary pressure. Gravity also promotes flocculation, therefore we compare the maximum values of the surface forces acting between the surfaces of two floculating particles to gravity. Finally

  5. Impact of polydispersity on multipolar resonant scattering in emulsions.

    PubMed

    Mascaro, Benoit; Brunet, Thomas; Poncelet, Olivier; Aristégui, Christophe; Raffy, Simon; Mondain-Monval, Olivier; Leng, Jacques

    2013-04-01

    The influence of size polydispersity on the resonant acoustic properties of dilute emulsions, made of fluorinated-oil droplets, is quantitatively investigated. Ultrasound attenuation and dispersion measurements on various samples with controlled size polydispersities, ranging from 1% to 13%, are found to be in excellent agreement with predictions based on the independent scattering approximation. By relating the particle-size distribution of the synthesized emulsions to the quality factor of the predicted multipolar resonances, the number of observable acoustic resonances is shown to be imposed by the sample polydispersity. These results are briefly discussed into the context of metamaterials for which scattering resonances are central to their effective properties. PMID:23556570

  6. Surface electric properties of emulsions of apolar reagents

    SciTech Connect

    Baichenko, A.A.; Baran, A.A.

    1986-09-01

    This article presents the results of studies of surface electric properties of kerosene and AAR-2 (apolar aromatized reagent) emulsons in water, which can be used in coal slime flotation, in presence of various salts and high-molecular flocculants. The data obtained were compared with the effect of electrolytes on the surface electric properties of a model emulsion of heptane in water stabilized by sodium hapthenate. The studies indicate that similarity of changes in the electrokinetic properties of various emulsions in presence of electrolytes and flocculants.

  7. Rapid and medium setting high float bituminous emulsions

    SciTech Connect

    Schilling, P.; Schreuders, H.G.

    1987-06-30

    This patent describes a rapid set high float aqueous bituminous emulsion-comprising bitumen, water, and from about 0.4% to about 0.6%, based on the weight of the emulsion, of an anionic emulsifier comprised of an alkaline solution of a combination of (1) 20% to 80% fatty acids selected from the group consisting of tall oil fatty acids, tallow fatty acids, and mixtures. (2) 20% to 80% of a product of the reaction of the fatty acids with a member of the group consists of acrylic acid, methacrylic acid, fumaric acid, and maleic anhydride.

  8. Mass-Transfer-Induced Multistep Phase Separation in Emulsion Droplets: Toward Self-Assembly Multilayered Emulsions and Onionlike Microspheres.

    PubMed

    Liang, Shuaishuai; Li, Jiang; Man, Jia; Chen, Haosheng

    2016-08-01

    Mass-transfer-induced multistep phase separation was found in emulsion droplets. The agent system consists of a monomer (ethoxylated trimethylolpropane triacrylate, ETPTA), an oligomer (polyethylene glycol diacrylate, PEGDA 700), and water. The PEGDA in the separated layers offered partial miscibility of all the components throughout the multistep phase-separation procedure, which was terminated by the depletion of PEGDA in the outermost layer. The number of separated portions was determined by the initial PEGDA content, and the initial droplet size influenced the mass-transfer process and consequently determined the sizes of the separated layers. The resultant multilayered emulsions were demonstrated to offer an orderly temperature-responsive release of the inner cores. Moreover, the emulsion droplets can be readily solidified into onionlike microspheres by ultraviolet light curing, providing a new strategy in designing particle structures.

  9. Mass-Transfer-Induced Multistep Phase Separation in Emulsion Droplets: Toward Self-Assembly Multilayered Emulsions and Onionlike Microspheres.

    PubMed

    Liang, Shuaishuai; Li, Jiang; Man, Jia; Chen, Haosheng

    2016-08-01

    Mass-transfer-induced multistep phase separation was found in emulsion droplets. The agent system consists of a monomer (ethoxylated trimethylolpropane triacrylate, ETPTA), an oligomer (polyethylene glycol diacrylate, PEGDA 700), and water. The PEGDA in the separated layers offered partial miscibility of all the components throughout the multistep phase-separation procedure, which was terminated by the depletion of PEGDA in the outermost layer. The number of separated portions was determined by the initial PEGDA content, and the initial droplet size influenced the mass-transfer process and consequently determined the sizes of the separated layers. The resultant multilayered emulsions were demonstrated to offer an orderly temperature-responsive release of the inner cores. Moreover, the emulsion droplets can be readily solidified into onionlike microspheres by ultraviolet light curing, providing a new strategy in designing particle structures. PMID:27427849

  10. DIMENSION STABILIZED FIXED PHOTOGRAPHIC TYPE EMULSION AND A METHOD FOR PRODUCING SAME

    DOEpatents

    Gilbert, F.C.

    1962-03-13

    A process is given for stabilizing the dimensions of fixed gelatin-base photographic type emulsions containing silver halide, and particularly to such emulsions containing large amounts of silver chloride for use as nuclear track emulsions, so that the dimensions of the final product are the same as or in a predetermined fixed ratio to the dimensions of the emulsions prior to exposure. The process comprises contacting an exposed, fixed emulsion with a solution of wood rosin dissolved in ethyl alcohol for times corresponding to the dimensions desired, and thereafter permitting the alcohol to evaporate. (AEC)

  11. Fluoropolymer-Based Emulsions for the Intravenous Delivery of Sevoflurane

    PubMed Central

    Fast, Jonathan P.; Perkins, Mark G.; Pearce, Robert A.; Waters, Ralph M.; Mecozzi, Sandro

    2009-01-01

    Background The intravenous delivery of halogenated volatile anesthetics has been previously achieved using phospholipid-stabilized emulsions, e.g. Intralipid. However, fluorinated volatile anesthetics, such as sevoflurane, are partially fluorophilic and do not mix well with classic non-fluorinated lipids. This effect limits the maximum amount of sevoflurane that can be stably emulsified in Intralipid to 3.5% v/v. This is a significant limitation to the potential clinical use of Intralipid-based emulsions. Methods The authors prepared a 20% v/v sevoflurane emulsion using a novel fluorinated surfactant and tested its effectiveness and therapeutic index by administering it to male Sprague-Dawley rats via intravenous injection into the jugular vein. The median effective dose to induce anesthesia (ED50), median lethal dose (LD50), and therapeutic index (LD50 / ED50) were determined. Anesthesia was measured by loss of the forepaw righting reflex. Results The ED50 and LD50 values were found to be 0.41 and 1.05 mL emulsion / kg body weight, respectively. These lead to a therapeutic index of 2.6, which compares favorably to previously determined values of emulsified isoflurane, as well as values for propofol and thiopental. Conclusions A novel semi-fluorinated surfactant was able to considerably increase the maximum amount of stably emulsified sevoflurane compared to Intralipid. These formulations can be used to rapidly induce anesthesia with bolus dosing from which recovery is smooth and rapid. PMID:18813044

  12. Vitamin E measurement in patients receiving intravenous lipid emulsions.

    PubMed

    Henton, D H; Merritt, R J; Hack, S

    1992-01-01

    Two methods for the determination of plasma vitamin E--high-pressure liquid chromatography and spectrophotofluorometry--were compared on samples from four groups of pediatric patients: children and infants receiving lipid emulsion as part of their parenteral nutrition regimen, neonates receiving parenteral nutrition who were not receiving lipid emulsion at the time of blood sampling, and short admission surgery control subjects. In control subjects and patients not receiving lipid emulsions, both methods yielded similar results for vitamin E as alpha-tocopherol. In contrast, in patients receiving lipid emulsion, the fluorometric method yielded values ranging from 200% to 300% greater than did high-pressure liquid chromatography. The source of the discrepancy is most probably the presence of naturally occurring non-alpha-tocopherol isomers in the lipid products, which add to the fluorescent measurement but are resolved by high-pressure liquid chromatography. This study confirms clinically that fluorescent measurement of vitamin E is no longer the method of choice for monitoring tocopherol status in intensive care nurseries.

  13. Isorefractive high internal phase emulsion organogels for light induced reactions.

    PubMed

    Zhang, Tao; Guo, Qipeng

    2016-03-25

    Isorefractive high internal phase emulsion (HIPE) organogels have been fabricated and investigated for light induced reactions. High transparency facilitates both the UV and visible light induced reactions within HIPE organogels. Transparent HIPE organogels are advantageous for light induced polymerizations, accelerating such polymerizations and enabling the preparation of large polyHIPE monoliths.

  14. Hadrons registration in emulsion chamber with carbon block

    NASA Technical Reports Server (NTRS)

    Tomaszewski, A.; Wlodarczyk, Z.

    1985-01-01

    Nuclear-electro-magnetic cascade (NEC) in X-ray emulsion chambers with carbon block, which are usually used in the Pamir experiment, was Monte-Carlo simulated. Going over from optical density to Summary E sub gamma is discussed. The hole of NEC in the interpretation of energy spectra is analyzed.

  15. Wettability of Freon hydrates in crude oil/brine emulsions.

    PubMed

    Høiland, S; Askvik, K M; Fotland, P; Alagic, E; Barth, T; Fadnes, F

    2005-07-01

    The surface energy of petroleum hydrates is believed to be a key parameter with regard to hydrate morphology and plugging tendency in petroleum production. As of today, the surface energy of natural gas hydrates is unknown, but will depend on the fluids in which they grow. In this work, the wettability of Freon hydrates is evaluated from their behavior in crude oil emulsions. For emulsions stabilized by colloidal particles, the particle wettability is a governing parameter for the emulsion behavior. The transition between continuous and dispersed phases as a function of brine volume in crude oil-brine emulsions containing Freon hydrates has been determined for 12 crude oils. Silica particles are used for comparison. The results show that phase inversion is highly dependent on crude oil properties. Based on the measured points of phase inversion, the wettability of the Freon hydrates generated in each system is evaluated as being oil-wet, intermediate-wet, or water-wet. Generation of oil-wet hydrates correlates with low hydrate plugging tendency. The formation of oil-wet hydrates will prevent agglomeration into large hydrate aggregates and plugs. Hence, it is believed that the method is applicable for differentiating oils with regard to hydrate morphology. PMID:15914170

  16. Stable Ultrathin-Shell Double Emulsions for Controlled Release.

    PubMed

    Zhao, Chun-Xia; Chen, Dong; Hui, Yue; Weitz, David A; Middelberg, Anton P J

    2016-06-01

    Double emulsions are normally considered as metastable systems and this limit in stability restricts their applications. To enhance their stability, the outer shell can be converted into a mechanically strong layer, for example, a polymeric layer, thus allowing improved performance. This conversion can be problematic for food and drug applications, as a toxic solvent is needed to dissolve the polymer in the middle phase and a high temperature is required to remove the solvent. This process can also be highly complex, for example, involving UV initiation of polymeric monomer crosslinking. In this study, we report the formation of biocompatible, water-in-oil-in-water (W/O/W) double emulsions with an ultrathin layer of fish oil. We demonstrate their application for the encapsulation and controlled release of small hydrophilic molecules. Without a trigger, the double emulsions remained stable for months, and the release of small molecules was extremely slow. In contrast, rapid release was achieved by osmolarity shock, leading to complete release within 2 h. This work demonstrates the significant potential of double emulsions, and provides new insights into their stability and practical applications. PMID:26934572

  17. Mannan-stabilized oil-in-water beverage emulsions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The stabilizing effect of spruce galactoglucomannan (GGM) on a model beverage emulsion system was studied and compared to that of guar gum and locust bean gum galactomannans, konjac glucomannan, and corn arabinoxylan. In addition, enzymatic modification was applied on guar gum to examine the effect ...

  18. A novel process for upgrading heavy oil emulsions

    SciTech Connect

    Ng, F.T.T.; Rintjema, R.T.

    1994-12-31

    Canada has extensive reserves of high sulfur heavy oils. These heavy oils are recovered primarily by steam injection techniques. As a result, the heavy oils are obtained as emulsions at well-heads. The heavy oils, being high in sulfur and metals, and low in hydrogen to carbon atomic ratio, require upgrading such as desulfurization and hydrocracking before it can be used in conventional refineries. Conventional emulsion treatment and desulfurization technology require multistage processing. Thus, alternative technologies for processing heavy oil emulsions would be attractive. The authors have recently developed a novel single stage process for upgrading emulsions via activation of water to provide hydrogen in situ for catalytic desulfurization and hydrocracking. Current work is focused on the desulfurization aspect of upgrading, using benzothiophene as the model sulfur compound and molybdic acid as the catalyst. At 340 C and a CO loading pressure of 600 psi, up to 86% sulfur removal was obtained. As well, in situ generated H{sub 2} was found to be more active than externally supplied molecular H{sub 2}. A likely pathway for desulfurization of benzothiophene was via the initial hydrogenation of benzothiophene to dihydrobenzothiophene followed by hydrogenolysis to give ethylbenzene and H{sub 2}S.

  19. Proton Linear Energy Transfer measurement using Emulsion Cloud Chamber

    NASA Astrophysics Data System (ADS)

    Shin, Jae-ik; Park, Seyjoon; Kim, Haksoo; Kim, Meyoung; Jeong, Chiyoung; Cho, Sungkoo; Lim, Young Kyung; Shin, Dongho; Lee, Se Byeong; Morishima, Kunihiro; Naganawa, Naotaka; Sato, Osamu; Kwak, Jungwon; Kim, Sung Hyun; Cho, Jung Sook; Ahn, Jung Keun; Kim, Ji Hyun; Yoon, Chun Sil; Incerti, Sebastien

    2015-04-01

    This study proposes to determine the correlation between the Volume Pulse Height (VPH) measured by nuclear emulsion and Linear Energy Transfer (LET) calculated by Monte Carlo simulation based on Geant4. The nuclear emulsion was irradiated at the National Cancer Center (NCC) with a therapeutic proton beam and was installed at 5.2 m distance from the beam nozzle structure with various thicknesses of water-equivalent material (PMMA) blocks to position with specific positions along the Bragg curve. After the beam exposure and development of the emulsion films, the films were scanned by S-UTS developed in Nagoya University. The proton tracks in the scanned films were reconstructed using the 'NETSCAN' method. Through this procedure, the VPH can be derived from each reconstructed proton track at each position along the Bragg curve. The VPH value indicates the magnitude of energy loss in proton track. By comparison with the simulation results obtained using Geant4, we found the correlation between the LET calculated by Monte Carlo simulation and the VPH measured by the nuclear emulsion.

  20. Formation of curcumin nanoparticles by flash nanoprecipitation from emulsions.

    PubMed

    Margulis, Katherine; Magdassi, Shlomo; Lee, Han Seung; Macosko, Christopher W

    2014-11-15

    Nanometric particles of a model hydrophobic substance curcumin were prepared by a novel method, namely, flash nanoprecipitation from a coarse oil-in-water emulsion. The method employs turbulent co-mixing of water with curcumin-loaded emulsion using manually-operated confined impingement jets mixer. A clear and stable dispersion of nanoparticles was formed in this process, and could be converted to dry, easily water-dispersible powder by spray drying. The mean size of the particles was about 40 nm by DLS, confirmed by Cryo-TEM. The obtained particles contained 20.4 wt% curcumin, X-ray analysis showed it was amorphous. The significant advantages of the studied process are its feasibility, speed and low cost. It does not require any special high-energy input equipment to reduce the droplet size of the initial emulsion as required by the vast majority of other methods, and relies on rapid turbulent mixing and on flow-induced shear stress formed in the simple, manually-operated mixer. Control experiments clearly indicate that employing emulsion, instead of a plain solution and flash nanoprecipitation instead of a simple antisolvent precipitation are advantageous in terms of particle size and stability. PMID:25168584

  1. Destabilization of Pickering emulsions using external electric fields.

    PubMed

    Hwang, Kyuho; Singh, Pushpendra; Aubry, Nadine

    2010-03-01

    It is known that emulsions can be stabilized by the presence of particles that get trapped at fluid-fluid interfaces and prevent adjacent drops from coalescing with one another. We show here that such emulsions, or Pickering emulsions, can be destabilized by applying external electric fields. This is demonstrated experimentally by studying water drops in decane and silicone oil drops in corn oil in the presence of micro-sized particles. It is shown that the primary phenomenon responsible for the destabilization is the motion of particles on the surface of drops in the presence of a uniform electric field. Although there should be no electrostatic forces acting on neutral particles in a uniform electric field, the presence of the drop itself introduces nonuniformity, which leads to dielectrophoretic forces acting on the particles and is thus responsible for particle motions along the drop surface. Particles translate to either the poles or the equator of the drop, depending on the relative dielectric constants of the particles, the surrounding fluid and the fluid within the drop. Such motions break the particle barrier, thus allowing for drops to merge with one another and therefore destabilizing the emulsion.

  2. Oxidative desulfurization of dibenzothiophene with molecular oxygen using emulsion catalysis.

    PubMed

    Lü, Hongying; Gao, Jinbo; Jiang, Zongxuan; Yang, Yongxing; Song, Bo; Li, Can

    2007-01-14

    Dibenzothiophene (DBT) is oxidized to the corresponding sulfoxide and sulfone in an emulsion system (W/O) composed of polyoxometalate anion [C(18)H(37)N(CH(3))3](5)[PV(2)Mo(10)O(40)] as both the surfactant and catalyst, using molecular oxygen as the oxidant and aldehyde as the sacrificial agent under mild conditions. PMID:17180229

  3. Removal of pesticides from aqueous solutions using liquid membrane emulsions

    SciTech Connect

    Norwood, V.M. III.

    1991-01-01

    Extractive liquid membrane technology is based on a water-in-oil emulsion as the vehicle to effect separation. An aqueous internal reagent phase is emulsified into an organic phase containing a surfactant and optional complexing agents. The emulsion, presenting a large membrane surface area, is then dispersed in an aqueous continuous phase containing the species to be removed. The desired species is transferred from the continuous, phase through the organic liquid membrane and concentrated in the internal reagent phase. Extraction and stripping occur simultaneously rather than sequentially as in conventional solvent extraction. Experiments were conducted to assess the feasibility of using liquid membranes to extract pesticides from rinsewaters typical of those generated by fertilizer/agrichemical dealers. A liquid membrane emulsion containing 10% NaOH as the internal reagent phase was used to extract herbicides from aqueous solution at a continuous phase:emulsion ratio of 5:1. Removals of 2,4-D, MCPA, Carbaryl, Diazinon, and Atrazine were investigated.

  4. Removal of pesticides from aqueous solutions using liquid membrane emulsions

    SciTech Connect

    Norwood, V.M. III

    1991-12-31

    Extractive liquid membrane technology is based on a water-in-oil emulsion as the vehicle to effect separation. An aqueous internal reagent phase is emulsified into an organic phase containing a surfactant and optional complexing agents. The emulsion, presenting a large membrane surface area, is then dispersed in an aqueous continuous phase containing the species to be removed. The desired species is transferred from the continuous, phase through the organic liquid membrane and concentrated in the internal reagent phase. Extraction and stripping occur simultaneously rather than sequentially as in conventional solvent extraction. Experiments were conducted to assess the feasibility of using liquid membranes to extract pesticides from rinsewaters typical of those generated by fertilizer/agrichemical dealers. A liquid membrane emulsion containing 10% NaOH as the internal reagent phase was used to extract herbicides from aqueous solution at a continuous phase:emulsion ratio of 5:1. Removals of 2,4-D, MCPA, Carbaryl, Diazinon, and Atrazine were investigated.

  5. Enhancing the antibacterial efficacy of isoeugenol by emulsion encapsulation.

    PubMed

    Krogsgård Nielsen, Christina; Kjems, Jørgen; Mygind, Tina; Snabe, Torben; Schwarz, Karin; Serfert, Yvonne; Meyer, Rikke Louise

    2016-07-16

    Food spoilage and foodborne illnesses are two global challenges for food manufacturers. Essential oils are natural antibacterials that could have a potential for use in food preservation. Unfortunately high concentrations are needed to obtain the desired antibacterial effect, and this limits their use in food due to their adverse organoleptic properties. Encapsulation could make essential oils more effective by concentrating them in the aqueous phase of the food matrix where the bacteria are present. Here we tested encapsulation of the essential oil isoeugenol in spray-dried emulsions as a means of making isoeugenol a more effective antibacterial for use in food preservation. We used β-lactoglobulin and n-OSA starch as emulsifiers, and some emulsions were coated with positively charged chitosan to promote the contact with bacteria through electrostatic interactions. The antibacterial efficacy was quantified as the minimal bactericidal concentration in growth media, milk and carrot juice. The emulsion encapsulation system developed in this study provided high loading capacities, and encapsulation enhanced the efficacy of isoeugenol against Gram-positive and -negative bacteria in media and carrot juice but not in milk. Chitosan-coating did not enhance the efficacy further, possibly due to the aggregation of the chitosan-coated emulsions. The encapsulation system is easy to upscale and should be applicable for encapsulation of similar essential oils. Therefore, we believe it has potential to be used for natural food preservation. PMID:27089032

  6. Pickering emulsions prepared by layered niobate K₄Nb₆O₁₇ intercalated with organic cations and photocatalytic dye decomposition in the emulsions.

    PubMed

    Nakato, Teruyuki; Ueda, Hiroaki; Hashimoto, Sachika; Terao, Ryosuke; Kameyama, Miyuki; Mouri, Emiko

    2012-08-01

    We investigated emulsions stabilized with particles of layered hexaniobate, known as a semiconductor photocatalyst, and photocatalytic degradation of dyes in the emulsions. Hydrophobicity of the niobate particles was adjusted with the intercalation of alkylammonium ions into the interlayer spaces to enable emulsification in a toluene-water system. After the modification of interlayer space with hexylammonium ions, the niobate stabilized water-in-oil (w/o) emulsions in a broad composition range. Optical microscopy showed that the niobate particles covered the surfaces of emulsion droplets and played a role of emulsifying agents. The niobate particles also enabled the generation of oil-in-water (o/w) emulsions in a limited composition range. Modification with dodecylammonium ions, which turned the niobate particles more hydrophobic, only gave w/o emulsions, and the particles were located not only at the toluene-water interface but also inside the toluene continuous phase. On the other hand, interlayer modification with butylammonium ions led to the formation of o/w emulsions. When porphyrin dyes were added to the system, the cationic dye was adsorbed on niobate particles at the emulsion droplets whereas the lipophilic dye was dissolved in toluene. Upon UV irradiation, both of the dyes were degraded photocatalytically. When the cationic and lipophilic porphyrin molecules were simultaneously added to the emulsions, both of the dyes were photodecomposed nonselectively.

  7. Immunomodulatory and Physical Effects of Oil Composition in Vaccine Adjuvant Emulsions

    PubMed Central

    Fox, Christopher B.; Baldwin, Susan L.; Duthie, Malcolm S.; Reed, Steven G.; Vedvick, Thomas S.

    2011-01-01

    Squalene-based oil-in-water emulsions have been used for years in some seasonal and pandemic influenza vaccines. However, concerns have been expressed regarding squalene source and potential biological activities. Little information is available regarding the immunomodulatory activity of squalene in comparison with other metabolizable oils in the context of oil-in-water emulsions formulated with vaccines. The present work describes the manufacture and physical characterization of emulsions composed of different classes of oils, including squalene, long chain triglycerides, a medium chain triglyceride, and a perfluorocarbon, all emulsified with egg phosphatidylcholine. Some differences were apparent among the non-squalene oils in terms of emulsion stability, including higher size polydispersity in the perfluorocarbon emulsion, more rapid visual instability at 60 °C for the long-chain triglyceride and perfluorocarbon emulsions, and an increased creaming rate in the medium-chain triglyceride emulsion at 60 °C as detected by laser scattering optical profiling. The biological activity of each of these emulsions was compared when formulated with either a recombinant malaria antigen or a split-virus inactivated influenza vaccine. Overall, vaccines containing the squalene emulsion elicited higher antibody titers and more abundant long-lived plasma cells than vaccines containing emulsions based on other oils. Since squalene-based emulsions show higher adjuvant potency compared to the other oils tested, non-squalene oils may be more suitable as carriers of amphiphilic or hydrophobic immunostimulatory molecules (such as TLR agonists) rather than as stand-alone adjuvants. PMID:21906648

  8. The influence of emulsion structure on the Maillard reaction of ghee.

    PubMed

    Newton, Angela E; Fairbanks, Antony J; Golding, Matt; Andrewes, Paul; Gerrard, Juliet A

    2015-04-15

    Food systems, such as cream and butter, have an emulsion or emulsion-like structure. When these food emulsions are heated to high temperatures to make products such as ghee, the Maillard reaction forms a range of volatile flavour compounds. The objective of this paper was to unravel the specific influence of emulsion structure on the Maillard reaction pathways that occur during the cooking of ghee using model systems. Switching the dispersed phase from oil to water provided a means of altering the ratios of volatile compounds produced in the cooked samples. The oil-in-water emulsion generated a volatile compound profile similar to that of the fat containing two phase model matrix, whereas the water-in-oil emulsion produced a different ratio of these compounds. The ability to generate different volatile compound profiles through the use of inverted emulsion structures could point to a new avenue for control of the Maillard reaction in high temperature food systems. PMID:25466150

  9. 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

  10. Preparation and stabilization of D-limonene Pickering emulsions by cellulose nanocrystals.

    PubMed

    Wen, Chunxia; Yuan, Qipeng; Liang, Hao; Vriesekoop, Frank

    2014-11-01

    The aim of this study was to investigate D-limonene Pickering emulsion stabilized by cellulose nanocrystals (CNCs) and factors that may affect its properties. CNCs were prepared by ammonium persulfate hydrolysis of corncob cellulose, and D-limonene Pickering emulsions were generated by ultrasonic homogenizing method. The morphology and size of the prepared emulsions with different CNCs concentrations were studied by optical microscopy and laser light diffraction. In addition, factors that may affect the stability of emulsions such as ionic concentration, pH and temperature were also studied. As indicated by the experiment data, when temperature rose, the stability to of emulsions would be increased, and the stability of emulsions was reduced with low pH or high salt concentration due to electrostatic screening of the negatively charged CNC particles. In conclusion, high stability of D-limonene Pickering emulsions could be obtained by CNCs.

  11. Preparation and stabilization of D-limonene Pickering emulsions by cellulose nanocrystals.

    PubMed

    Wen, Chunxia; Yuan, Qipeng; Liang, Hao; Vriesekoop, Frank

    2014-11-01

    The aim of this study was to investigate D-limonene Pickering emulsion stabilized by cellulose nanocrystals (CNCs) and factors that may affect its properties. CNCs were prepared by ammonium persulfate hydrolysis of corncob cellulose, and D-limonene Pickering emulsions were generated by ultrasonic homogenizing method. The morphology and size of the prepared emulsions with different CNCs concentrations were studied by optical microscopy and laser light diffraction. In addition, factors that may affect the stability of emulsions such as ionic concentration, pH and temperature were also studied. As indicated by the experiment data, when temperature rose, the stability to of emulsions would be increased, and the stability of emulsions was reduced with low pH or high salt concentration due to electrostatic screening of the negatively charged CNC particles. In conclusion, high stability of D-limonene Pickering emulsions could be obtained by CNCs. PMID:25129799

  12. Unique Dual Functions for Carbon Dots in Emulsion Preparations: Costabilization and Fluorescence Probing.

    PubMed

    Tan, Hua; Liu, Wenxia; Gong, Bei; Zhang, Wei; Li, Haidong; Yu, Dehai; Wang, Huili; Li, Guodong; Lucia, Lucian A

    2015-09-01

    Recently, carbon dots (CDs) have drawn much attention as evidenced by their incorporation into many branches of science and engineering. Herein, a further unique application is elucidated: CDs that are synthesized by the hydrothermal treatment of gelatin for a dual functionality as expressed in costabilization of particle-based emulsions and their concomitant role as fluorescent probes. CDs either with or without gelatin matrixes induce the aggregation of Laponite particles. The introduction of CDs thus enhanced the stability of Laponite-stabilized emulsions and promoted the formation of multiple emulsions and emulsions with fine and uniform droplets when the CD-to-Laponite mass ratio was less than 45% and exceeded 60%, respectively. However, CDs without gelatin matrixes show slightly higher efficiency than CDs within gelatin matrixes for the costabilization of emulsions. CDs also costabilized emulsions with Laponite to allow the distribution of Laponite particles to be traced and the emulsion profiled under UV.

  13. The influence of emulsion structure on the Maillard reaction of ghee.

    PubMed

    Newton, Angela E; Fairbanks, Antony J; Golding, Matt; Andrewes, Paul; Gerrard, Juliet A

    2015-04-15

    Food systems, such as cream and butter, have an emulsion or emulsion-like structure. When these food emulsions are heated to high temperatures to make products such as ghee, the Maillard reaction forms a range of volatile flavour compounds. The objective of this paper was to unravel the specific influence of emulsion structure on the Maillard reaction pathways that occur during the cooking of ghee using model systems. Switching the dispersed phase from oil to water provided a means of altering the ratios of volatile compounds produced in the cooked samples. The oil-in-water emulsion generated a volatile compound profile similar to that of the fat containing two phase model matrix, whereas the water-in-oil emulsion produced a different ratio of these compounds. The ability to generate different volatile compound profiles through the use of inverted emulsion structures could point to a new avenue for control of the Maillard reaction in high temperature food systems.

  14. Mechanism of aerobic biological destabilisation of wool scour effluent emulsions.

    PubMed

    Poole, Andrew J; Cord-Ruwisch, Ralf; William Jones, F

    2005-07-01

    Wool scouring effluent is a highly polluted industrial wastewater in which the main pollutant, wool wax, is held in a stable oil-in-water emulsion by non-ionic detergent. The use of microbial action to cause emulsion destabilisation has been proposed as a new treatment strategy for this effluent stream. This strategy aims at improving aerobic treatment performance by physically removing the high-COD, slowly bio-degradable wool wax from the system without bio-degradation. The mechanism by which an aerobic-mixed culture destabilises the wool scouring effluent emulsion was investigated. Our results show that destabilisation is due to partial bio-degradation of both the scouring detergent and the wool wax. Cleavage of the wool wax esters was the first stage in wax degradation, when 40-50% of wax was de-emulsified. Over the same period, detergent degradation was low, at 7-21%. With further incubation, detergent degradation increased, aiding further breakdown of the emulsion. The degradation of the detergent, a nonylphenol ethoxylate, resulted in both a reduction in molar concentration (of up to 82%) and a shortening of the ethoxylate chain length. The latter reduced the hydrophile-lipophile balance (HLB) from 12 to approximately 7, thereby reducing the ability of the residual detergent to stabilise the emulsion. Analysis of the emulsified and de-emulsified wax fractions could not identify a group of compounds that were preferentially de-emulsified based on molecular weight or polarity. These findings will assist in using a de-emulsification strategy in both existing and new treatment systems in order to save on aeration costs and treatment times for biological treatment of this highly polluted wastewater. PMID:15979119

  15. Mechanism of aerobic biological destabilisation of wool scour effluent emulsions.

    PubMed

    Poole, Andrew J; Cord-Ruwisch, Ralf; William Jones, F

    2005-07-01

    Wool scouring effluent is a highly polluted industrial wastewater in which the main pollutant, wool wax, is held in a stable oil-in-water emulsion by non-ionic detergent. The use of microbial action to cause emulsion destabilisation has been proposed as a new treatment strategy for this effluent stream. This strategy aims at improving aerobic treatment performance by physically removing the high-COD, slowly bio-degradable wool wax from the system without bio-degradation. The mechanism by which an aerobic-mixed culture destabilises the wool scouring effluent emulsion was investigated. Our results show that destabilisation is due to partial bio-degradation of both the scouring detergent and the wool wax. Cleavage of the wool wax esters was the first stage in wax degradation, when 40-50% of wax was de-emulsified. Over the same period, detergent degradation was low, at 7-21%. With further incubation, detergent degradation increased, aiding further breakdown of the emulsion. The degradation of the detergent, a nonylphenol ethoxylate, resulted in both a reduction in molar concentration (of up to 82%) and a shortening of the ethoxylate chain length. The latter reduced the hydrophile-lipophile balance (HLB) from 12 to approximately 7, thereby reducing the ability of the residual detergent to stabilise the emulsion. Analysis of the emulsified and de-emulsified wax fractions could not identify a group of compounds that were preferentially de-emulsified based on molecular weight or polarity. These findings will assist in using a de-emulsification strategy in both existing and new treatment systems in order to save on aeration costs and treatment times for biological treatment of this highly polluted wastewater.

  16. Oil components modulate physical characteristics and function of the natural oil emulsions as drug or gene delivery system.

    PubMed

    Chung, H; Kim, T W; Kwon, M; Kwon, I C; Jeong, S Y

    2001-04-28

    Oil-in-water (o/w) type lipid emulsions were formulated by using 18 different natural oils and egg phosphatidylcholine (egg PC) to investigate how emulsion particle size and stability change with different oils. Cottonseed, linseed and evening primrose oils formed emulsions with very large and unstable particles. Squalene, light mineral oil and jojoba bean oil formed stable emulsions with small particles. The remaining natural oils formed moderately stable emulsions. Emulsions with smaller initial particle size were more stable than those with larger particles. The correlation between emulsion size made with different oils and two physical properties of the oils was also investigated. The o/w interfacial tension and particle size of the emulsion were inversely proportional. The effect of viscosity was less pronounced. To study how the oil component in the emulsion modulates the in vitro release characteristics of lipophilic drugs, three different emulsions loaded with two different drugs were prepared. Squalene, soybean oil and linseed oil emulsions represented the most, medium and the least stable systems, respectively. For the lipophilic drugs, release was the slowest from the most stable squalene emulsion, followed by soybean oil and then by linseed oil emulsions. Cationic emulsions were also prepared with the above three different oils as gene carriers. In vitro transfection activity was the highest for the most stable squalene emulsion followed by soybean oil and then by linseed oil emulsions. Even though the in vitro transfection activity of emulsions were lower than the liposome in the absence of serum, the activity of squalene emulsion, for instance, was ca. 30 times higher than that of liposome in the presence of 80% (v/v) serum. In conclusion, the choice of oil component in o/w emulsion is important in formulating emulsion-based drug or gene delivery systems.

  17. Alternating copolymerization of propylene oxide with biorenewable terpene-based cyclic anhydrides: a sustainable route to aliphatic polyesters with high glass transition temperatures.

    PubMed

    Van Zee, Nathan J; Coates, Geoffrey W

    2015-02-23

    The alternating copolymerization of propylene oxide with terpene-based cyclic anhydrides catalyzed by chromium, cobalt, and aluminum salen complexes is reported. The use of the Diels-Alder adduct of α-terpinene and maleic anhydride as the cyclic anhydride comonomer results in amorphous polyesters that exhibit glass transition temperatures (Tg ) of up to 109 °C. The polymerization conditions and choice of catalyst have a dramatic impact on the molecular weight distribution, the relative stereochemistry of the diester units along the polymer chain, and ultimately the Tg of the resulting polymer. The aluminum salen complex exhibits exceptional selectivity for copolymerization without transesterification or epimerization side reactions. The resulting polyesters are highly alternating and have high molecular weights and narrow polydispersities.

  18. Copolymerization as a Strategy to Combine Epoxidized Linseed Oil and Furfuryl Alcohol: The Design of a Fully Bio-Based Thermoset.

    PubMed

    Pin, Jean-Mathieu; Guigo, Nathanaël; Vincent, Luc; Sbirrazzuoli, Nicolas; Mija, Alice

    2015-12-21

    Epoxidized linseed oil and furfuryl alcohol are bio-sourced monomers known for their high-potential applications in materials science. In this work, we propose the association of these monomers through copolymerization reactions with the target to design fully bio-based thermosets. Herein, investigations on cationic polymerization reactivity have been explored using differential scanning calorimetry. The obtained structures have been confirmed by IR spectroscopy and 2 D NMR spectroscopy, which revealed the principal chain connections. In spite of the multiple capabilities of chemical connections, which include copolymerization and cross-linking, the obtained networks are homogeneous as confirmed by dynamic mechanical analysis and SEM. Furthermore, the copolymer demonstrates a semiductile behavior if subjected to tensile measurements (tensile strain at break ≈40 %), which is a significant advance in terms of its applications as a furanic bio-based thermoset material. PMID:26663869

  19. Preparation of Syndiotactic Poly(vinyl alcohol)/Poly(vinyl pivalate/vinyl acetate) Microspheres with Radiopacity Using Suspension Copolymerization and Saponification

    NASA Astrophysics Data System (ADS)

    Seok Lyoo, Won; Wook Cha, Jin; Young Kwak, Kun; Jae Lee, Young; Yong Jeon, Han; Sik Chung, Yong; Kyun Noh, Seok

    2010-06-01

    To prepare Poly(vinyl pivalate/vinyl acetate) [P(VPi/VAc)] microspheres with radiopacity, the suspension copolymerization approach in the presence of aqueous radiopaque nanoparticles was used. After, The P(VPi/VAc) microspheres with radiopacity were saponified in heterogeneous system, and then P(VPi/VAc) microspheres without aggregates were converted to s-PVA/P(VPi/VAc) microspheres of skin/core structure through the heterogeneous surface saponification. Radiopacity of microspheres was confirmed with Computed tomography (CT).

  20. Copolymerization and terpolymerization of carbon dioxide/propylene oxide/phthalic anhydride using a (salen)Co(III) complex tethering four quaternary ammonium salts

    PubMed Central

    Jeon, Jong Yeob; Eo, Seong Chan; Varghese, Jobi Kodiyan

    2014-01-01

    Summary The (salen)Co(III) complex 1 tethering four quaternary ammonium salts, which is a highly active catalyst in CO2/epoxide copolymerizations, shows high activity for propylene oxide/phthalic anhydride (PO/PA) copolymerizations and PO/CO2/PA terpolymerizations. In the PO/PA copolymerizations, full conversion of PA was achieved within 5 h, and strictly alternating copolymers of poly(1,2-propylene phthalate)s were afforded without any formation of ether linkages. In the PO/CO2/PA terpolymerizations, full conversion of PA was also achieved within 4 h. The resulting polymers were gradient poly(1,2-propylene carbonate-co-phthalate)s because of the drift in the PA concentration during the terpolymerization. Both polymerizations showed immortal polymerization character; therefore, the molecular weights were determined by the activity (g/mol-1) and the number of chain-growing sites per 1 [anions in 1 (5) + water (present as impurity) + ethanol (deliberately fed)], and the molecular weight distributions were narrow (M w/M n, 1.05–1.5). Because of the extremely high activity of 1, high-molecular-weight polymers were generated (M n up to 170,000 and 350,000 for the PO/PA copolymerization and PO/CO2/PA terpolymerization, respectively). The terpolymers bearing a substantial number of PA units (f PA, 0.23) showed a higher glass-transition temperature (48 °C) than the CO2/PO alternating copolymer (40 °C). PMID:25161738

  1. In vitro drug release behavior, mechanism and antimicrobial activity of rifampicin loaded low molecular weight PLGA-PEG-PLGA triblock copolymeric nanospheres.

    PubMed

    Gajendiran, M; Divakar, S; Raaman, N; Balasubramanian, S

    2013-12-01

    Poly (lactic-co-glycolic acid) (PLGA (92:8)) and a series of PLGA-PEG-PLGA tri block copolymers were synthesized by direct melt polycondensation. The copolymers were characterized by FTIR, and 1HNMR spectroscopic techniques, viscosity, gel permeation chromatography (GPC) and powder x-ray diffraction (XRD). The rifampicin (RIF) loaded polymeric nanospheres (NPs) were prepared by ultrasonication-W/O emulsification technique. The NPs have been characterized by field emission scanning electron microscopy (FESEM), TEM, powder X-ray diffraction (XRD), UVvisible spectroscopy and DLS measurements. The drug loaded triblock copolymeric NPs have five folds higher drug content and drug loading efficiency than that of PLGA microspheres (MPs). The in vitro drug release study shows that the drug loaded NPs showed an initial burst release after that sustained release up to 72 h. All the triblock copolymeric NPs follow anomalous drug diffusion mechanism while the PLGA MPs follow non-Fickian super case-II mechanism up to 12 h. The overall in-vitro release follows second order polynomial kinetics up to 72 h. The antimicrobial activity of the RIF loaded polymer NPs was compared with that of pure RIF and tetracycline (TA). The RIF loaded triblock copolymeric NPs inhibited the bacterial growth more effectively than the pure RIF and TA.

  2. Functional and surface-active membranes from poly(vinylidene fluoride)-graft-poly(acrylic acid) prepared via RAFT-mediated graft copolymerization.

    PubMed

    Ying, L; Yu, W H; Kang, E T; Neoh, K G

    2004-07-01

    Poly (vinylidene fluoride) (PVDF) with "living" poly (acrylic acid) (PAAc) side chains (PVDF-g-PAAc) was prepared by reversible addition-fragmentation chain transfer (RAFT)-mediated graft copolymerization of acrylic acid (AAc) with the ozone-pretreated PVDF. The chemical composition and structure of the copolymers were characterized by elemental analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The copolymer could be readily cast into pH-sensitive microfiltration (MF) membranes with enriched living PAAc graft chains on the surface (including the pore surfaces) by phase inversion in an aqueous medium. The surface composition of the membranes was determined by X-ray photoelectron spectroscopy. The morphology of the membranes was characterized by scanning electron microscopy. The pore size distribution of the membranes was found to be much more uniform than that of the corresponding membranes cast from PVDF-g-PAAc prepared by the "conventional" free-radical graft copolymerization process. Most important of all, the MF membranes with surface-tethered PAAc macro chain transfer agents, or the living membrane surfaces, could be further functionalized via surface-initiated block copolymerization with N-isopropylacrylamide (NIPAAM) to obtain the PVDF-g-PAAc-b-PNIPAAM MF membranes, which exhibited both pH- and temperature-dependent permeability to aqueous media. PMID:16459627

  3. Heat Transfer in Boiling Dilute Emulsion with Strong Buoyancy

    NASA Astrophysics Data System (ADS)

    Freeburg, Eric Thomas

    Little attention has been given to the boiling of emulsions compared to that of boiling in pure liquids. The advantages of using emulsions as a heat transfer agent were first discovered in the 1970s and several interesting features have since been studied by few researchers. Early research focuses primarily on pool and flow boiling and looks to determine a mechanism by which the boiling process occurs. This thesis looks at the boiling of dilute emulsions in fluids with strong buoyant forces. The boiling of dilute emulsions presents many favorable characteristics that make it an ideal agent for heat transfer. High heat flux electronics, such as those seen in avionics equipment, produce high heat fluxes of 100 W/cm2 or more, but must be maintained at low temperatures. So far, research on single phase convection and flow boiling in small diameter channels have yet to provide an adequate solution. Emulsions allow the engineer to tailor the solution to the specific problem. The fluid can be customized to retain the high thermal conductivity and specific heat capacity of the continuous phase while enhancing the heat transfer coefficient through boiling of the dispersed phase component. Heat transfer experiments were carried out with FC-72 in water emulsions. FC-72 has a saturation temperature of 56 °C, far below that of water. The parameters were varied as follows: 0% ≤ epsilon ≤ 1% and 1.82 x 1012 ≤ RaH ≤ 4.42 x 1012. Surface temperatures along the heated surface reached temperature that were 20 °C in excess of the dispersed phase saturation temperature. An increase of ˜20% was seen in the average Nusselt numbers at the highest Rayleigh numbers. Holography was used to obtain images of individual and multiple FC-72 droplets in the boundary layer next to the heated surface. The droplet diameters ranged from 0.5 mm to 1.3 mm. The Magnus effect was observed when larger individual droplets were injected into the boundary layer, causing the droplets to be pushed

  4. Effect of the degree of substitution of octenyl succinic anhydride-banana starch on emulsion stability.

    PubMed

    Bello-Pérez, Luis A; Bello-Flores, Christopher A; Nuñez-Santiago, María del Carmen; Coronel-Aguilera, Claudia P; Alvarez-Ramirez, J

    2015-11-01

    Banana starch was esterified with octenylsuccinic anhydride (OSA) at different degree substitution (DS) and used to stabilize emulsions. Morphology, emulsion stability, emulsification index, rheological properties and particle size distribution of the emulsions were tested. Emulsions dyed with Solvent Red 26 showed affinity for the oil phase. Backscattering light showed three regions in the emulsion where the emulsified region was present. Starch concentration had higher effect in the emulsification index (EI) than the DS used in the study because similar values were found with OSA-banana and native starches. However, OSA-banana presented greater stability of the emulsified region. Rheological tests in emulsions with OSA-banana showed G'>G" values and low dependence of G' with the frequency, indicating a dominant elastic response to shear. When emulsions were prepared under high-pressure conditions, the emulsions with OSA-banana starch with different DS showed a bimodal distribution of particle size. The emulsion with OSA-banana starch and the low DS showed similar mean droplet diameter than its native counterpart. In contrast, the highest DS led to the highest mean droplet diameter. It is concluded that OSA-banana starch with DS can be used to stabilize specific emulsion types.

  5. Effect of the degree of substitution of octenyl succinic anhydride-banana starch on emulsion stability.

    PubMed

    Bello-Pérez, Luis A; Bello-Flores, Christopher A; Nuñez-Santiago, María del Carmen; Coronel-Aguilera, Claudia P; Alvarez-Ramirez, J

    2015-11-01

    Banana starch was esterified with octenylsuccinic anhydride (OSA) at different degree substitution (DS) and used to stabilize emulsions. Morphology, emulsion stability, emulsification index, rheological properties and particle size distribution of the emulsions were tested. Emulsions dyed with Solvent Red 26 showed affinity for the oil phase. Backscattering light showed three regions in the emulsion where the emulsified region was present. Starch concentration had higher effect in the emulsification index (EI) than the DS used in the study because similar values were found with OSA-banana and native starches. However, OSA-banana presented greater stability of the emulsified region. Rheological tests in emulsions with OSA-banana showed G'>G" values and low dependence of G' with the frequency, indicating a dominant elastic response to shear. When emulsions were prepared under high-pressure conditions, the emulsions with OSA-banana starch with different DS showed a bimodal distribution of particle size. The emulsion with OSA-banana starch and the low DS showed similar mean droplet diameter than its native counterpart. In contrast, the highest DS led to the highest mean droplet diameter. It is concluded that OSA-banana starch with DS can be used to stabilize specific emulsion types. PMID:26256319

  6. Pickering emulsions stabilized by a lipophilic surfactant and hydrophilic platelike particles.

    PubMed

    Wang, Jun; Yang, Fei; Tan, Junjun; Liu, Guopeng; Xu, Jian; Sun, Dejun

    2010-04-20

    Liquid paraffin-water emulsions were prepared by homogenizing oil phases containing sorbitan oleate (Span 80) and aqueous phases containing layered double hydroxide (LDH) particles or Laponite particles. While water-in-oil (w/o) emulsions are obtained by combining LDH with Span 80, the emulsions stabilized by Laponite-Span 80 are always o/w types regardless of the Span 80 concentration. Laser-induced fluorescent confocal micrographs indicate that particles are absorbed on the emulsion surfaces, suggesting all the emulsions are stabilized by the particles. The difference of the particle-stabilized emulsion type may be explained by comparing particle contact angles and the oil-water interfacial tensions, indicating that more Span 80 molecules are adsorbed on the LDH particles than on Laponite. Apparently, the LDH particles are rendered more hydrophobic by Span 80, resulting in the formation of w/o emulsions. The long-term stability of the emulsions was also compared. Emulsions stabilized by Span 80 alone completely separate into two bulk phases of oil and water after 3 months. However, emulsion stability is greatly enhanced with the addition of LDH or Laponite particles. This synergism was accounted for by an increase of the dilational viscoelasticity modulus of the oil-water interface after particles were added to the aqueous phase. This increase indicates that the gel-like particle layer stays at the oil-water interface and resists emulsion coalescence. Scanning electron microscope (SEM) images display the presence of a firm layer surrounding the emulsion droplets and a three-dimensional particle network which extends into the bulk phase aiding emulsion stability.

  7. Preparation and characterization of PVDF-glass fiber composite membrane reinforced by interfacial UV-grafting copolymerization.

    PubMed

    Luo, Nan; Xu, Rongle; Yang, Min; Yuan, Xing; Zhong, Hui; Fan, Yaobo

    2015-12-01

    A novel inorganic-organic composite membrane, namely poly(vinylidene fluoride) PVDF-glass fiber (PGF) composite membrane, was prepared and reinforced by interfacial ultraviolet (UV)-grafting copolymerization to improve the interfacial bonding strength between the membrane layer and the glass fiber. The interfacial polymerization between inorganic-organic interfaces is a chemical cross-linking reaction that depends on the functionalized glass fiber with silane coupling (KH570) as the initiator and the polymer solution with acrylamide monomer (AM) as the grafting block. The Fourier transform infrared spectrometer-attenuated total reflectance (FTIR-ATR) spectra and the energy dispersive X-ray (EDX) pictures of the interface between the glass fiber and polymer matrix confirmed that the AM was grafted to the surface of the glass fiber fabric and that the grafting polymer was successfully embedded in the membrane matrix. The formation mechanisms, permeation, and anti-fouling performance of the PGF composite membrane were measured with different amounts of AM in the doping solutions. The results showed that the grafting composite membrane improved the interfacial bonding strength and permeability, and the peeling strength was improved by 32.6% for PGF composite membranes with an AM concentration at 2wt.%.

  8. Holographic polymer dispersed liquid crystal system utilizing the co-polymerizations with siloxane compounds and polypropylene glycol derivatives

    NASA Astrophysics Data System (ADS)

    Takanokura, Tomoe; Kurashige, Makio; Ishida, Kazutoshi; Ohyagi, Yasuyuki; Watanabe, Masachika; Cho, Yeong Hee

    2011-03-01

    Holographic polymer dispersed liquid crystal (HPDLC) has a feature that can control diffraction of light by applying electric field. HPDLC can be used for optical elements such as an optical switch, or a polarized beam splitter etc. One of the reactive systems for making HPDLC is well known photopolymerization-induced phase separation (PIPS). The performance of HPDLC by PIPS is dependent on distribution of oriented liquid crystal (LC) molecules, or size and shape of LC droplets. These are controlled by chemical structure or functional group of polymer matrix. In this report, Organic-inorganic hybrid materials having sensitivity at 532 nm were synthesized. Polymer matrix was formed with co-polymerization of siloxane-containing materials and poly (propylene glycol) derivatives functionalized with methacrylate groups. Siloxane chain was introduced in polymer matrix to encourage phase separation of LC and stabilize grating structure. In addition, poly (propylene glycol) derivatives were designed to control polymerization rate and extent of phase separation of LC. The characterization of HPDLC was evaluated in terms of diffraction efficiency, contrast between diffraction and transparency modes by applying voltage, and switch speed. As a result, the separation ratio of p-polarized light and s-polarized light was 100:1. The value of ▵n was 0.075, and the index matching of both polymer-rich layer and LC-rich layer was completed at voltage of 17V/μm.

  9. Synthesis of α(1→4)-linked non-natural mannoglucans by α-glucan phosphorylase-catalyzed enzymatic copolymerization.

    PubMed

    Baba, Ryotaro; Yamamoto, Kazuya; Kadokawa, Jun-Ichi

    2016-10-20

    α-Glucan phosphorylase catalyzes enzymatic polymerization of α-d-glucose 1-phosphate (Glc-1-P) as a monomer from a maltooligosaccharide primer to produce α(1→4)-glucan, i.e., amylose, with liberating inorganic phosphate (Pi). Because of quite weak specificity for the recognition of substrates by thermostable α-glucan phosphorylase (from Aquifex aeolicus VF5), in this study, we investigated the enzymatic copolymerization of Glc-1-P with its analogue monomer, α-d-mannose 1-phosphate (Man-1-P) under the conditions for removal of Pi as the precipitate with ammonium and magnesium in ammonia buffer containing Mg(2+) ion to produce α(1→4)-linked non-natural mannoglucans composed of Glc/Man units. The reaction was conducted in different feed ratios using the maltotriose primer at 40°C for 7days. The MALDI-TOF mass and (1)H NMR spectra of the products fully supported the mannoglucan structures. PMID:27474652

  10. Furfuralcohol Co-Polymerized Urea Formaldehyde Resin-derived N-Doped Microporous Carbon for CO2 Capture

    NASA Astrophysics Data System (ADS)

    Liu, Zhen; Yang, Yi; Du, Zhenyu; Xing, Wei; Komarneni, Sridhar; Zhang, Zhongdong; Gao, Xionghou; Yan, Zifeng

    2015-08-01

    Carbon-based adsorbent is considered to be one of the most promising adsorbents for CO2 capture form flue gases. In this study, a series of N-doped microporous carbon materials were synthesized from low cost and widely available urea formaldehyde resin co-polymerized with furfuralcohol. These N-doped microporous carbons showed tunable surface area in the range of 416-2273 m2 g-1 with narrow pore size distribution within less than 1 nm and a high density of the basic N functional groups (2.93-13.92 %). Compared with the carbon obtained from urea resin, the addition of furfuralcohol apparently changed the surface chemical composition and pore size distribution, especially ultramicropores as can be deduced from the X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), and pore size distribution measurements and led to remarkable improvement on CO2 adsorption capacity. At 1 atm, N-doped carbons activated at 600 °C with KOH/UFFC weight ratio of 2 (UFFA-2-600) showed the highest CO2 uptake of 3.76 and 1.57 mmol g-1 at 25 and 75 °C, respectively.

  11. Radiation-induced graft copolymerization of poly(ethylene glycol) monomethacrylate onto deoxycholate-chitosan nanoparticles as a drug carrier

    NASA Astrophysics Data System (ADS)

    Pasanphan, Wanvimol; Rattanawongwiboon, Thitirat; Rimdusit, Pakjira; Piroonpan, Thananchai

    2014-01-01

    Poly(ethylene glycol) monomethacrylate-grafted-deoxycholate chitosan nanoparticles (PEGMA-g-DCCSNPs) were successfully prepared by radiation-induced graft copolymerization. The hydrophilic poly(ethylene glycol) monomethacrylate was grafted onto deoxycholate-chitosan in an aqueous system. The radiation-absorbed dose is an important parameter on degree of grafting, shell thickness and particle size of PEGMA-g-DCCSNPs. Owing to their amphiphilic architecture, PEGMA-g-DCCSNPs self-assembled into spherical core-shell nanoparticles in aqueous media. The particle size of PEGMA-g-DCCSNPs measured by TEM varied in the range of 70-130 nm depending on the degree of grafting as well as the irradiation dose. Berberine (BBR) as a model drug was encapsulated into the PEGMA-g-DCCSNPs. Drug release study revealed that the BBR drug was slowly released from PEGMA-g-DCCSNPs at a mostly constant rate of 10-20% in PBS buffer (pH 7.4) at 37 °C over a period of 23 days.

  12. High-energy radiation monitoring based on radio-fluorogenic co-polymerization. I: Small volume in situ probe.

    PubMed

    Warman, J M; de Haas, M P; Luthjens, L H

    2009-05-21

    A method of radiation dosimetry is described which is based on the radiation-induced initiation of polymerization of a bulk monomer (e.g. methyl methacrylate) containing a small concentration (about 100 ppm) of a compound which is non-fluorescent but which becomes highly fluorescent when it is incorporated into a growing polymer chain of the bulk monomer. We call the overall process 'radio-fluorogenic co-polymerization' or RFCP for short. The method is illustrated by results on the in situ monitoring of the accumulated dose within the irradiation chamber of a cobalt-60 gamma-ray source using a small plastic capsule containing about 0.2 ml of an RFCP solution. Remote monitoring of the fluorescence is carried out on a timescale of seconds using optical fibres connecting the probe to a 360 nm LED excitation source and a miniature spectrophotometer. The fluorescence is permanent and the intensity is linearly proportional to the accumulated dose from a few tenths of a gray up to hundreds of gray. The sensitivity to dose depends on the polymerizable monomer used and obeys a square root dependence on dose rate over the range studied, 0.27-3.76 Gy min(-1). The polymeric nature of the fluorescent product suggests that the RFCP effect could be used to provide fixed two- or three-dimensional fluorescent images of dose deposition in gel films or phantoms. PMID:19420430

  13. Porous polymer monoliths with large surface area and functional groups prepared via copolymerization of protected functional monomers and hypercrosslinking.

    PubMed

    Maya, Fernando; Svec, Frantisek

    2013-11-22

    A new approach to the preparation of porous polymer monoliths possessing both large surface area and functional groups has been developed. The chloromethyl groups of poly(styrene-co-4-acetoxystyrene-co-vinylbenzyl chloride-co-divinylbenzene) monolith enable post-polymerization hypercrosslinking catalyzed by ferric chloride in dichloroethane leading to a multitude of small pores thus enhancing the surface area. The acetoxy functionalities are easily deprotected using hydrazine to produce polar phenolic hydroxyl groups, which would be difficult to obtain by direct copolymerization of hydroxyl-containing monomers. The hypercrosslinking and deprotection reactions as well as their sequence were studied in detail with bulk polymer monoliths containing up to 50% 4-acetoxystyrene and its progress monitored by infrared spectrometry and nitrogen adsorption/desorption measurements. No significant difference was found for both possible successions. All monoliths were also prepared in a capillary column format, then deprotected and hypercrosslinked. Capillary columns were tested for the separation of small molecules using reversed phase and normal phase chromatographic modes. For polymer monoliths containing 50% deprotected 4-acetoxystyrene, column efficiencies of 40,000 plates/m for benzene in reversed phase mode and 31,800 plates/m for nitrobenzene in normal phase mode, were obtained. The percentage of hydroxyl groups in the monoliths enables modulation of polarity of the stationary phase. They also represent functionalities that are potentially suitable for further modifications and formation of new types of stationary phases for liquid chromatography.

  14. Fabrication of Fluoropolymer Microtubes via RAFT Copolymerization of N,N'-Methylene Bisacrylamide Gel Fibers and Fluoromonomer.

    PubMed

    Li, Qi; Wang, Yi; Tang, Liming

    2015-06-01

    Fluoropolymer microtubes with a smooth surface were fabricated in more than 70 % yield via reversible addition fragmentation chain transfer (RAFT) co-polymerization of N,N'-methylene bisacrylamide (MBA) gel fibers as both template and monomer, 2-(perfluoro-3-methylbutyl)ethyl acrylate (R-3420) as co-monomer, and pentaerythritol tetraacrylate (PET4A) as cross-linker. The resulting fluoropolymer microtubes were characterized fully by SEM, TEM, EDS, XPS, and FT-IR. The influence of the monomer composition on the yields and morphologies of the tubes were investigated in detail. The results indicated that polymer microtubes with a smooth surface were obtained at suitable amounts of R-3420 and PET4A. Because of the decreased solubility of MBA gel fibers, the wall thickness increased as more R-3420 was used. In the presence of PET4A, the solution polymerization could be facilitated and more R-3420 could be attached onto the tubes based on FT-IR analysis. The water contact angle and swelling ratio measurements both revealed the low hydrophilicity and high lipophilicity of the fluoropolymer microtubes, which made the sample able to absorb toluene selectively in a water/toluene two-phase system. PMID:25786386

  15. Homogeneous graft copolymerization of styrene onto cellulose in a sulfur dioxide-diethylamine-dimethyl sulfoxide cellulose solvent

    SciTech Connect

    Tsuzuki, M.; Hagiwara, I.; Shiraishi, N.; Yokota, T.

    1980-12-01

    Graft copolymerization of styrene onto cellulose was studied in a homogeneous system (SO/sub 2/(liquid)- diethylamine (DEA)-dimethyl sulfoxide (DMSO) medium)) by ..gamma..-ray mutual irradiation technique. At the same time, homopolymerization of styrene was also examined separately in DMSO, SO/sub 2/-DMSO, DEA-DMSO, and SO/sub 2/-DEA-DMSO media by the same technique. Polymerization of styrene hardly occurs on concentrations above 10 mole SO/sub 2/-DEA complex per mole glucose unit. Maximum percent grafting was obtained in concentrations of 4 mole, after which it decreased rapidly. Total conversion and percent grafting increased with the irradiation time. The value (=0.55) of the slope of the total conversion rate plotted against the dose was only a little higher than the 1/2 which was expected from normal kinetics. No retardation in homopolymerization of styrene in DMSO, SO/sub 2/-DMSO, and DEA-DMSO was evident, while the retardation of homopolymerization in the SO/sub 2/-DEA-DMSO medium was measurable. Sulfur atoms were detected in the polymers obtained in both of SO/sub 2/-DMSO and SO/sub 2/-DEA-DMSO solutions. All of the molecular weights of polymers obtained in the present experiment were very low (3.9 x 10/sup 3/-1.75 x 10/sup 4/).

  16. On the transport of emulsions in porous media

    SciTech Connect

    Cortis, Andrea; Ghezzehei, Teamrat A.

    2007-06-27

    Emulsions appear in many subsurface applications includingbioremediation, surfactant-enhanced remediation, and enhancedoil-recovery. Modeling emulsion transport in porous media is particularlychallenging because the rheological and physical properties of emulsionsare different from averages of the components. Current modelingapproaches are based on filtration theories, which are not suited toadequately address the pore-scale permeability fluctuations and reductionof absolute permeability that are often encountered during emulsiontransport. In this communication, we introduce a continuous time randomwalk based alternative approach that captures these unique features ofemulsion transport. Calculations based on the proposed approach resultedin excellent match with experimental observations of emulsionbreakthrough from the literature. Specifically, the new approach explainsthe slow late-time tailing behavior that could not be fitted using thestandard approach. The theory presented in this paper also provides animportant stepping stone toward a generalizedself-consistent modeling ofmultiphase flow.

  17. Analysis of relativistic nucleus-nucleus interactions in emulsion chambers

    NASA Technical Reports Server (NTRS)

    Mcguire, Stephen C.

    1987-01-01

    The development of a computer-assisted method is reported for the determination of the angular distribution data for secondary particles produced in relativistic nucleus-nucleus collisions in emulsions. The method is applied to emulsion detectors that were placed in a constant, uniform magnetic field and exposed to beams of 60 and 200 GeV/nucleon O-16 ions at the Super Proton Synchrotron (SPS) of the European Center for Nuclear Research (CERN). Linear regression analysis is used to determine the azimuthal and polar emission angles from measured track coordinate data. The software, written in BASIC, is designed to be machine independent, and adaptable to an automated system for acquiring the track coordinates. The fitting algorithm is deterministic, and takes into account the experimental uncertainty in the measured points. Further, a procedure for using the track data to estimate the linear momenta of the charged particles observed in the detectors is included.

  18. Aerogel Microparticles from Oil-in-Oil Emulsion Systems.

    PubMed

    Gu, Senlong; Zhai, Chunhao; Jana, Sadhan C

    2016-06-01

    This paper reports preparation of polymer aerogel microparticles via sol-gel reactions inside micrometer size droplets created in an oil-in-oil emulsion system. The oil-in-oil emulsion system is obtained by dispersing in cyclohexane the droplets of the sols of polybenzoxazine (PBZ) or polyimide (PI) prepared in dimethylformamide. The sol droplets transform into harder gel microparticles due to sol-gel reactions. Finally, the aerogel microparticles are recovered using supercritical drying of the gel microparticles. The PBZ and PI aerogel microparticles prepared in this manner show mean diameter 32.7 and 40.0 μm, respectively, mesoporous internal structures, and surface area 55.4 and 512.0 m(2)/g, respectively. Carbonization of PBZ aerogel microparticles maintains the mesoporous internal structures but yields narrower pore size distribution. PMID:27183146

  19. Field-induced structure of confined ferrofluid emulsion

    SciTech Connect

    Lawrence, E.M.; Ivey, M.L.; Flores, G.A.; Liu, J. . Dept. of Physics and Astronomy); Bibette, J. ); Richard, J. )

    1994-09-01

    Field-induced phase behavior of a confined monodisperse ferrofluid emulsion was studied using optical microscopy, light transmission, and static light scattering techniques. Upon application of magnetic field, randomly-dispersed magnetic emulsion droplets form solid structures at [lambda] = 1.5, where [lambda] is defines as the ratio of the dipole-dipole interaction energy to the thermal energy at room temperature. The new solid phase consists of either single droplet chains, columns, or worm-like clusters, depending on the volume fraction, cell thickness and rate of field application. For the column phase, an equilibrium structure of equally-sized and spaced columns was observed. The measurements taken for cell thickness 5[mu]m [<=] L [<=] 500 [mu]m and volume fraction 0.04 show the column spacing to be reasonably described by d = 1.49 L[sup 0.34].

  20. Flocculation of inverted emulsions. Influence of electrostatic repulsion of droplets

    SciTech Connect

    Bedenko, V.G.; Pertsov, A.V.

    1988-09-01

    The dependence of the degree of flocculation of emulsions of water in various hydrocarbons stabilized with respect to the coalescence by nonionogenic surfactants and of the zeta potential of the droplets on the presence of additions of chromium stearate has been studied experimentally. The introduction of 0.01-0.03% chromium stearate into an emulsion results in the complete prevention of flocculation and a significant increase in the /zeta/ potential. The observed correlation of the stability toward flocculation and the /zeta/ potential points out the significant role of the stability of the systems studied. The theoretical analysis of the energy of interaction of the droplets with consideration of the collective character of the interaction is consistent with such a conclusion.

  1. Bioreactor droplets from liposome-stabilized all-aqueous emulsions

    NASA Astrophysics Data System (ADS)

    Dewey, Daniel C.; Strulson, Christopher A.; Cacace, David N.; Bevilacqua, Philip C.; Keating, Christine D.

    2014-08-01

    Artificial bioreactors are desirable for in vitro biochemical studies and as protocells. A key challenge is maintaining a favourable internal environment while allowing substrate entry and product departure. We show that semipermeable, size-controlled bioreactors with aqueous, macromolecularly crowded interiors can be assembled by liposome stabilization of an all-aqueous emulsion. Dextran-rich aqueous droplets are dispersed in a continuous polyethylene glycol (PEG)-rich aqueous phase, with coalescence inhibited by adsorbed ~130-nm diameter liposomes. Fluorescence recovery after photobleaching and dynamic light scattering data indicate that the liposomes, which are PEGylated and negatively charged, remain intact at the interface for extended time. Inter-droplet repulsion provides electrostatic stabilization of the emulsion, with droplet coalescence prevented even for submonolayer interfacial coatings. RNA and DNA can enter and exit aqueous droplets by diffusion, with final concentrations dictated by partitioning. The capacity to serve as microscale bioreactors is established by demonstrating a ribozyme cleavage reaction within the liposome-coated droplets.

  2. From bijels to Pickering emulsions: A lattice Boltzmann study

    NASA Astrophysics Data System (ADS)

    Jansen, Fabian; Harting, Jens

    2011-04-01

    Particle stabilized emulsions are ubiquitous in the food and cosmetics industry, but our understanding of the influence of microscopic fluid-particle and particle-particle interactions on the macroscopic rheology is still limited. In this paper we present a simulation algorithm based on a multicomponent lattice Boltzmann model to describe the solvents combined with a molecular dynamics solver for the description of the solved particles. It is shown that the model allows a wide variation of fluid properties and arbitrary contact angles on the particle surfaces. We demonstrate its applicability by studying the transition from a “bicontinuous interfacially jammed emulsion gel” (bijel) to a “Pickering emulsion” in dependence on the contact angle, the particle concentration, and the ratio of the solvents.

  3. Asphalt emulsion sealing of uranium mill tailings. 1979 annual report

    SciTech Connect

    Hartley, J.N.; Koehmstedt, P.L.; Esterl, D.J.; Freeman, H.D.

    1980-06-01

    Uranium mill tailings are a source of low-level radiation and radioactive materials that may be released into the environment. Stabilization or disposal of these tailings in a safe and environmentally sound way is necessary to minimize radon exhalation and other radioactive releases. One of the most promising concepts for stabilizing uranium tailings is being investigated at the Pacific Northwest Laboratory: the use of asphalt emulsion to contain radon and other potentially hazardous materials in uranium tailings. Results of these studies indicate that radon flux from uranium tailings can be reduced by greater than 99% by covering the tailings with an asphalt emulsion that is poured on or sprayed on (3.0 to 7.0 mm thick), or mixed with some of the tailings and compacted to form an admixture seal (2.5 to 15.2 cm) containing 18 wt % residual asphalt.

  4. Aerogel Microparticles from Oil-in-Oil Emulsion Systems.

    PubMed

    Gu, Senlong; Zhai, Chunhao; Jana, Sadhan C

    2016-06-01

    This paper reports preparation of polymer aerogel microparticles via sol-gel reactions inside micrometer size droplets created in an oil-in-oil emulsion system. The oil-in-oil emulsion system is obtained by dispersing in cyclohexane the droplets of the sols of polybenzoxazine (PBZ) or polyimide (PI) prepared in dimethylformamide. The sol droplets transform into harder gel microparticles due to sol-gel reactions. Finally, the aerogel microparticles are recovered using supercritical drying of the gel microparticles. The PBZ and PI aerogel microparticles prepared in this manner show mean diameter 32.7 and 40.0 μm, respectively, mesoporous internal structures, and surface area 55.4 and 512.0 m(2)/g, respectively. Carbonization of PBZ aerogel microparticles maintains the mesoporous internal structures but yields narrower pore size distribution.

  5. High energy primary electron spectrum observed by the emulsion chamber

    NASA Technical Reports Server (NTRS)

    Nishimura, J.; Fujii, M.; Aizu, H.; Hiraiwa, N.; Taira, T.; Kobayashi, T.; Niu, K.; Koss, T. A.; Lord, J. J.; Golden, R. L.

    1978-01-01

    A detector of the emulsion chamber type is used to measure the energy spectrum of cosmic-ray electrons. Two large emulsion chambers, each having an area of 40 by 50 sq cm, are exposed for about 25.5 hr at an average pressure altitude of 3.9 mbar. About 500 high-energy cascades (no less than about 600 GeV) are detected by searching for dark spots on the X-ray films. A power-law energy dependence formula is derived for the spectrum of primary cosmic-ray electrons in the energy region over 100 GeV. The results are in good agreement with the transition curves obtained previously by theoretical and Monte Carlo calculations.

  6. Enzymatically activated emulsions stabilised by interfacial nanofibre networks.

    PubMed

    Moreira, Inês P; Sasselli, Ivan Ramos; Cannon, Daniel A; Hughes, Meghan; Lamprou, Dimitrios A; Tuttle, Tell; Ulijn, Rein V

    2016-03-01

    We report on-demand formation of emulsions stabilised by interfacial nanoscale networks. These are formed through biocatalytic dephosphorylation and self-assembly of Fmoc(9-fluorenylmethoxycarbonyl)dipeptide amphiphiles in aqueous/organic mixtures. This is achieved by using alkaline phosphatase which transforms surfactant-like phosphorylated precursors into self-assembling aromatic peptide amphiphiles (Fmoc-tyrosine-leucine, Fmoc-YL) that form nanofibrous networks. In biphasic organic/aqueous systems, these networks form preferentially at the interface thus providing a means of emulsion stabilisation. We demonstrate on-demand emulsification by enzyme addition, even after storage of the biphasic mixture for several weeks. Experimental (Fluorescence, FTIR spectroscopy, fluorescence microscopy, electron microscopy, atomic force microscopy) and computational techniques (atomistic molecular dynamics) are used to characterise the interfacial self-assembly process. PMID:26905042

  7. Effect of irradiated pork on physicochemical properties of meat emulsions

    NASA Astrophysics Data System (ADS)

    Choi, Yun-Sang; Sung, Jung-Min; Jeong, Tae-Jun; Hwang, Ko-Eun; Song, Dong-Heon; Ham, Youn-Kyung; Kim, Hyun-Wook; Kim, Young-Boong; Kim, Cheon-Jei

    2016-02-01

    The effect of pork irradiated with doses up to 10 kGy on meat emulsions formulated with carboxy methyl cellulose (CMC) was investigated. Raw pork was vacuums packaged at a thickness of 2.0 cm and irradiated by X-ray linear accelerator (15 kW, 5 MeV). The emulsion had higher lightness, myofibrillar protein solubility, total protein solubility, and apparent viscosity with increasing doses, whereas cooking loss, total expressible fluid separation, and hardness decreased. There were no significant differences in fat separation, sarcoplasmic protein solubility, springiness, and cohesiveness. Our results indicated that it is treatment by ionizing radiation which causes the effects the physicochemical properties of the final raw meat product.

  8. Measuring the Free Fall of Antihydrogen with Emulsion Detectors

    NASA Astrophysics Data System (ADS)

    Pistillo, C.

    2014-06-01

    The AEgIS experiment at CERN is designed to perform the first direct measurement of gravitational interaction between antimatter and matter by detecting the fall of a horizontally accelerated cold antihydrogen beam in the Earth's gravitational field. The spatial resolution of the position sensitive detector is a key issue for the success of the experiment. For this reason, the employment of emulsion film detectors is being considered and an intense R&D is being conducted to define the use of this technology in the AEgIS apparatus. We present the results of test beams conducted in 2012, when emulsion film detectors were directly exposed to a ˜ 100 keV antiproton beam and annihilation vertices successfully reconstructed with a few micrometers resolution. The prospects for the realization of the final detector are also presented.

  9. Antioxidant activity and emulsion-stabilizing effect of pectic enzyme treated pectin in soy protein isolate-stabilized oil/water emulsion.

    PubMed

    Huang, Ping-Hsiu; Lu, Hao-Te; Wang, Yuh-Tai; Wu, Ming-Chang

    2011-09-14

    The antioxidant activity of pectic enzyme treated pectin (PET-pectin) prepared from citrus pectin by enzymatic hydrolysis and its potential use as a stabilizer and an antioxidant for soy protein isolate (SPI)-stabilized oil in water (O/W) emulsion were investigated. Trolox equivalent antioxidant capacity (TEAC) was found to be positively associated with molecular weight (M(w)) of PET-pectin and negatively associated with degree of esterification (DE) of PET-pectin. PET-pectin (1 kDa and 11.6% DE) prepared from citrus pectin after 24 h of hydrolysis by commercial pectic enzyme produced by Aspergillus niger expressed higher α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity, TEAC, and reducing power than untreated citrus pectin (353 kDa and 60% DE). The addition of PET-pectin could increase both emulsifying activity (EA) and emulsion stability (ES) of SPI-stabilized O/W emulsion. When the SPI-stabilized lipid droplet was coated with the mixture of PET-pectin and pectin, the EA and ES of the emulsion were improved more than they were when the lipid droplet was coated with either pectin or PET-pectin alone. The amount of secondary oxidation products (thiobarbituric acid reactive substances) produced in the emulsion prepared with the mixture of SPI and PET-pectin was less than the amount produced in the emulsion prepared with either SPI or SPI/pectin. These results suggest that PET-pectin has an emulsion-stabilizing effect and lipid oxidation inhibition ability on SPI-stabilized emulsion. Therefore, PET-pectin can be used as a stabilizer as well as an antioxidant in plant origin in SPI-stabilized O/W emulsion and thus prolong the shelf life of food emulsion. PMID:21806056

  10. Antioxidant activity and emulsion-stabilizing effect of pectic enzyme treated pectin in soy protein isolate-stabilized oil/water emulsion.

    PubMed

    Huang, Ping-Hsiu; Lu, Hao-Te; Wang, Yuh-Tai; Wu, Ming-Chang

    2011-09-14

    The antioxidant activity of pectic enzyme treated pectin (PET-pectin) prepared from citrus pectin by enzymatic hydrolysis and its potential use as a stabilizer and an antioxidant for soy protein isolate (SPI)-stabilized oil in water (O/W) emulsion were investigated. Trolox equivalent antioxidant capacity (TEAC) was found to be positively associated with molecular weight (M(w)) of PET-pectin and negatively associated with degree of esterification (DE) of PET-pectin. PET-pectin (1 kDa and 11.6% DE) prepared from citrus pectin after 24 h of hydrolysis by commercial pectic enzyme produced by Aspergillus niger expressed higher α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging activity, TEAC, and reducing power than untreated citrus pectin (353 kDa and 60% DE). The addition of PET-pectin could increase both emulsifying activity (EA) and emulsion stability (ES) of SPI-stabilized O/W emulsion. When the SPI-stabilized lipid droplet was coated with the mixture of PET-pectin and pectin, the EA and ES of the emulsion were improved more than they were when the lipid droplet was coated with either pectin or PET-pectin alone. The amount of secondary oxidation products (thiobarbituric acid reactive substances) produced in the emulsion prepared with the mixture of SPI and PET-pectin was less than the amount produced in the emulsion prepared with either SPI or SPI/pectin. These results suggest that PET-pectin has an emulsion-stabilizing effect and lipid oxidation inhibition ability on SPI-stabilized emulsion. Therefore, PET-pectin can be used as a stabilizer as well as an antioxidant in plant origin in SPI-stabilized O/W emulsion and thus prolong the shelf life of food emulsion.

  11. 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.

  12. Waste of cleaning emulsion sewage as inhibitors of steel corrosion

    NASA Astrophysics Data System (ADS)

    Fazullin, D. D.; Mavrin, G. V.; Shaikhiev, I. G.

    2016-06-01

    The article describes the corrosion test of steel of the brand 20 in the stratal water. To increase corrosion resistance as a corrosion inhibitor the concentrate waste emulsion of the mark "Incam- 1" was provided. The article presents studies of the corrosion rate with different dosages of corrosion inhibitor in the stratal water. Based on these research results are revealed that the degree of protection of steel is 27% at a dosage of 3.8 g / dm3.

  13. MOF-polymer composite microcapsules derived from Pickering emulsions.

    PubMed

    Huo, Jia; Marcello, Marco; Garai, Ashesh; Bradshaw, Darren

    2013-05-21

    Hollow composite microcapsules are prepared by the assembly of pre-formed nanocrystals of metal-organic frameworks (MOFs) around emulsion droplets, followed by interfacial polymerisation of the interior. The micropores of the MOF crystals embedded within a semipermeable hierarchically structured polymeric membrane are an effective combination for the retention of encapsulated dye molecules. Release can be triggered however by acid dissolution of the MOF component.

  14. Coagulation and electrocoagulation of oil-in-water emulsions.

    PubMed

    Cañizares, Pablo; Martínez, Fabiola; Jiménez, Carlos; Sáez, Cristina; Rodrigo, Manuel A

    2008-02-28

    In this work the efficiencies of the chemical and the electrochemical break-up of oil-in-water (O/W) emulsions with hydrolyzing aluminium salts are compared. It has been obtained that the efficiency of the processes does not depend directly on the dosing technology, but on the total concentration of aluminium and pH. This latter parameter changes in a different way in the chemical and the electrochemical processes: the pH increases during the electrochemical experiments since the electrochemical system leads to the formation of aluminum hydroxide as a net final product, but it decreases in the conventional ones due to the acid properties of the aluminum salts added (AlCl3 or Al2(SO4)3). The break-up of the emulsions only takes place in the range of pHs between 5 and 9, and the amount of aluminium necessary to produce the destabilization of the emulsion is proportional to the oil concentration. Electrolytes containing chlorides improve COD removal as compared with those containing sulphate ions. Aluminium hydroxide precipitates were found to be the primary species present in solution in the conditions in which the breaking process is favoured. Consequently, the attachment of more than one droplet of oil at a time to a charged precipitate-particle (bridging flocculation) was proposed as the primary destabilization mechanism. PMID:17583426

  15. Enhanced fluorescence emitted by microdroplets containing organic dye emulsions.

    PubMed

    Boni, M; Nastasa, V; Andrei, I R; Staicu, Angela; Pascu, M L

    2015-01-01

    In this paper, laser beam resonant interaction with pendant microdroplets that are seeded with a laser dye (Rhodamine 6G (Rh6G)) water solution or oily Vitamin A emulsion with Rhodamine 6G solution in water is investigated through fluorescence spectra analysis. The excitation is made with the second harmonic generated beam emitted by a pulsed Nd:YAG laser system at 532 nm. The pendant microdroplets containing emulsion exhibit an enhanced fluorescence signal. This effect can be explained as being due to the scattering of light by the sub-micrometric drops of oily Vitamin A in emulsion and by the spherical geometry of the pendant droplet. The droplet acts as an optical resonator amplifying the fluorescence signal with the possibility of producing lasing effect. Here, we also investigate how Rhodamine 6G concentration, pumping laser beam energies and number of pumping laser pulses influence the fluorescence behavior. The results can be useful in optical imaging, since they can lead to the use of smaller quantities of fluorescent dyes to obtain results with the same quality. PMID:25784965

  16. Dynamical and structural signatures of the glass transition in emulsions

    NASA Astrophysics Data System (ADS)

    Zhang, Chi; Gnan, Nicoletta; Mason, Thomas G.; Zaccarelli, Emanuela; Scheffold, Frank

    2016-09-01

    We investigate structural and dynamical properties of moderately polydisperse emulsions across an extended range of droplet volume fractions ϕ, encompassing fluid and glassy states up to jamming. Combining experiments and simulations, we show that when ϕ approaches the glass transition volume fraction {φg} , dynamical heterogeneities and amorphous order arise within the emulsion. In particular, we find an increasing number of clusters of particles having five-fold symmetry (i.e. the so-called locally favoured structures, LFS) as ϕ approaches {φg} , saturating to a roughly constant value in the glassy regime. However, contrary to previous studies, we do not observe a corresponding growth of medium-range crystalline order; instead, the emergence of LFS is decoupled from the appearance of more ordered regions in our system. We also find that the static correlation lengths associated with the LFS and with the fastest particles can be successfully related to the relaxation time of the system. By contrast, this does not hold for the length associated with the orientational order. Our study reveals the existence of a link between dynamics and structure close to the glass transition even in the absence of crystalline precursors or crystallization. Furthermore, the quantitative agreement between our confocal microscopy experiments and Brownian dynamics simulations indicates that emulsions are and will continue to be important model systems for the investigation of the glass transition and beyond.

  17. Fat emulsion infusion potentiates coagulation activation during human endotoxemia.

    PubMed

    van der Poll, T; Coyle, S M; Levi, M; Boermeester, M A; Braxton, C C; Jansen, P M; Hack, C E; Lowry, S F

    1996-01-01

    Intravenous fat emulsions are frequently given to malnourished patients who are prone to suffer from infectious complications. As injection of low dose endotoxin represents a model to study the human response to acute infection, we sought to determine the effect of lipid emulsion infusion on endotoxin-induced activation of the hemostatic mechanism in man. Ten healthy men received a bolus intravenous injection of endotoxin (lot EC-5; 20 U/kg) midway through a 4-h infusion (125 ml/h) of either dextrose 5% (n = 5) or Intralipid 20% (n = 5). Lipid infusion potentiated endotoxin-induced coagulation activation, as indicated by higher plasma levels of the prothrombin fragment F1 + 2 and of thrombin-antithrombin III complexes (both p < 0.05 for the difference between groups). However, lipid infusion did not influence the fibrinolytic response to intravenous endotoxin, as reflected by similar increases in the levels of tissue-type plasminogen activator and plasmin-alpha 2-antiplasmin complexes in both groups. Endotoxin-induced appearance of plasminogen activator inhibitor type I was enhanced by lipid infusion (p < 0.05). These data suggest that fat emulsion infusion may enhance the tendency towards thrombotic complications in patients with infections.

  18. Functional properties of ultrasonically generated flaxseed oil-dairy emulsions.

    PubMed

    Shanmugam, Akalya; Ashokkumar, Muthupandian

    2014-09-01

    This study reports on the functional properties of 7% flaxseed oil/milk emulsion obtained by sonication (OM) using 20 kHz ultrasound (US) at 176 W for 1-8 min in two different delivery formulae, viz., ready-to-drink (RTD) and lactic acid gel. The RTD emulsions showed no change in viscosity after sonication for up to 8 min followed by storage up to a minimum of 9 days at 4±2 °C. Similarly, the oxidative stability of the RTD emulsion was studied by measuring the conjugated diene hydroperoxides (CD). The CD was unaffected after 8 min of ultrasonic processing. The safety aspect of US processing was evaluated by measuring the formation of CD at different power levels. The functional properties of OM gels were evaluated by small and large scale deformation studies. The sonication process improved the gelation characteristics, viz., decreased gelation time, increased elastic nature, decreased syneresis and increased gel strength. The presence of finer sono-emulsified oil globules, stabilized by partially denatured whey proteins, contributed to the improvements in the gel structure in comparison to sonicated and unsonicated pasteurized homogenized skim milk (PHSM) gels. A sono-emulsification process of 5 min followed by gelation for about 11 min can produce gels of highest textural attibutes.

  19. Functional properties of ultrasonically generated flaxseed oil-dairy emulsions.

    PubMed

    Shanmugam, Akalya; Ashokkumar, Muthupandian

    2014-09-01

    This study reports on the functional properties of 7% flaxseed oil/milk emulsion obtained by sonication (OM) using 20 kHz ultrasound (US) at 176 W for 1-8 min in two different delivery formulae, viz., ready-to-drink (RTD) and lactic acid gel. The RTD emulsions showed no change in viscosity after sonication for up to 8 min followed by storage up to a minimum of 9 days at 4±2 °C. Similarly, the oxidative stability of the RTD emulsion was studied by measuring the conjugated diene hydroperoxides (CD). The CD was unaffected after 8 min of ultrasonic processing. The safety aspect of US processing was evaluated by measuring the formation of CD at different power levels. The functional properties of OM gels were evaluated by small and large scale deformation studies. The sonication process improved the gelation characteristics, viz., decreased gelation time, increased elastic nature, decreased syneresis and increased gel strength. The presence of finer sono-emulsified oil globules, stabilized by partially denatured whey proteins, contributed to the improvements in the gel structure in comparison to sonicated and unsonicated pasteurized homogenized skim milk (PHSM) gels. A sono-emulsification process of 5 min followed by gelation for about 11 min can produce gels of highest textural attibutes. PMID:24713146

  20. Microemulsion versus emulsion as effective carrier of hydroxytyrosol.

    PubMed

    Chatzidaki, Maria D; Arik, Nehir; Monteil, Julien; Papadimitriou, Vassiliki; Leal-Calderon, Fernando; Xenakis, Aristotelis

    2016-01-01

    Two edible Water-in-Oil (W/O) dispersions, an emulsion that remains kinetically stable and a microemulsion which is spontaneously formed, transparent and thermodynamically stable, were developed for potential use as functional foods, due to their ability to be considered as matrices to encapsulate biologically active hydrophilic molecules. Both systems contained Medium Chain Triglycerides (MCT) as the continuous phase and were used as carriers of Hydroxytyrosol (HT), a hydrophilic antioxidant of olive oil. A low energy input fabrication process of the emulsion was implemented. The obtained emulsion contained 1.3% (w/w) of surfactants and 5% (w/w) aqueous phase. The spontaneously formed microemulsion contained 4.9% (w/w) of surfactants and 2% (w/w) aqueous phase. A comparative study in terms of structural characterization of the systems in the absence and presence of HT was carried out. Particle size distribution obtained by Dynamic Light Scattering (DLS) technique and interfacial properties of the surfactants' layer, examined by Electron Paramagnetic Resonance (EPR) spectroscopy indicated the involvement of HT in the surfactant membrane. Finally, the proposed systems were studied for the scavenging activity of the encapsulated antioxidant toward galvinoxyl stable free radical showing a high scavenging activity of HT in both systems. PMID:25999235

  1. Olive Oil Based Emulsions in Frozen Puff Pastry Production

    NASA Astrophysics Data System (ADS)

    Gabriele, D.; Migliori, M.; Lupi, F. R.; de Cindio, B.

    2008-07-01

    Puff pastry is an interesting food product having different industrial applications. It is obtained by laminating layers of dough and fats, mainly shortenings or margarine, having specific properties which provides required spreading characteristic and able to retain moisture into dough. To obtain these characteristics, pastry shortenings are usually saturated fats, however the current trend in food industry is mainly oriented towards unsatured fats such as olive oil, which are thought to be safer for human health. In the present work, a new product, based on olive oil, was studied as shortening replacer in puff pastry production. To ensure the desired consistency, for the rheological matching between fat and dough, a water-in-oil emulsion was produced based on olive oil, emulsifier and a hydrophilic thickener agent able to increase material structure. Obtained materials were characterized by rheological dynamic tests in linear viscoelastic conditions, aiming to setup process and material consistency, and rheological data were analyzed by using the weak gel model. Results obtained for tested emulsions were compared to theological properties of a commercial margarine, adopted as reference value for texture and stability. Obtained emulsions are characterized by interesting rheological properties strongly dependent on emulsifier characteristics and water phase composition. However a change in process temperature during fat extrusion and dough lamination seems to be necessary to match properly typical dough rheological properties.

  2. Preparation and evaluation of minoxidil foamable emu oil emulsion.

    PubMed

    Shatalebi, M A; Rafiei, Y

    2014-01-01

    The aim of this work was to develop and evaluate a minoxidil foamable emu oil emulsion with the purpose of improving minoxidil permeation into the skin, increasing hair growth, reducing skin irritation, and increasing consumer compliance. Minoxidil was dissolved in a solvent system comprising ethanol: glycerin: lactic acid: water (10:20:5:65). The foamable emulsion was prepared by mixing the oil phase with minoxidil solution using different amount of various emulsifiers. Seventeen formulations were prepared and the most stable foamable emulsion was selected and evaluated for various pharmaceutical parameters such as homogeneity, pH, stability to centrifugal stress, freeze-thaw and foamability. The adopted formulation showed good pharmaceutical characteristics. In vitro release rate of the formulations were evaluated using Franz diffusion cell using phosphate buffer pH 7.4 and ethanol as the receiver medium at sink condition. The release rate of formulations was found to obey Higuchi kinetic model. Experimental animal study was performed to evaluate hair growth potential of the formulation. Different cyclic phases of hair follicles, like anagen, and telogen phases, were determined at one month period. Histological study after treatment with adopted formulation exhibited greater number of hair follicles in anagenic phase (96%) which were higher as compared to marketed 5% minoxidil solution (Pakdaru® 70%) and the control group (42%). From animal study it was concluded that the selected formulation exhibited a significant potency in promoting hair growth in comparison with marketed 5% minoxidil solution Pakdaru®. PMID:25657781

  3. Particle shape anisotropy in pickering emulsions: cubes and peanuts.

    PubMed

    de Folter, Julius W J; Hutter, Eline M; Castillo, Sonja I R; Klop, Kira E; Philipse, Albert P; Kegel, Willem K

    2014-02-01

    We have investigated the effect of particle shape in Pickering emulsions by employing, for the first time, cubic and peanut-shaped particles. The interfacial packing and orientation of anisotropic microparticles are revealed at the single-particle level by direct microscopy observations. The uniform anisotropic hematite microparticles adsorb irreversibly at the oil-water interface in monolayers and form solid-stabilized o/w emulsions via the process of limited coalescence. Emulsions were stable against further coalescence for at least 1 year. We found that cubes assembled at the interface in monolayers with a packing intermediate between hexagonal and cubic and average packing densities of up to 90%. Local domains displayed densities even higher than theoretically achievable for spheres. Cubes exclusively orient parallel with one of their flat sides at the oil-water interface, whereas peanuts preferentially attach parallel with their long side. Those peanut-shaped microparticles assemble in locally ordered, interfacial particle stacks that may interlock. Indications for long-range capillary interactions were not found, and we hypothesize that this is related to the observed stable orientations of cubes and peanuts that marginalize deformations of the interface. PMID:24020650

  4. Emulsion-templated fully reversible protein-in-oil gels.

    PubMed

    Romoscanu, Alexandre I; Mezzenga, Raffaele

    2006-08-29

    We have developed a new method allowing us to transform low-viscous apolar fluids into elastic solids with a shear elastic modulus of the order of 10(3)-10(5) Pa. The elasticity of the elastic solid is provided by a percolating 3D network of proteins, which are originally adsorbed at the interface of an oil-in-water emulsion template. By cross-linking the protein films at the interface and upon removal of water, the template is driven into a structure resembling a dry foam where the protein interfaces constitute the walls of the foam and the air is replaced by oil confined within polyhedral, closely packed droplets. Depending on the density of the protein network, the final material consists of chemically unmodified oil in a proportion of 95 to 99.9%. The physical properties of the elastic solid obtained can be tuned by changing either the average diameter size of the emulsion template or the cross-linking process of the protein film. However, the original low-viscosity emulsion can be restored by simply rehydrating the solidified fluid. Therefore, the present procedure offers an appealing strategy to build up solid properties for hydrophobic liquids while preserving the low viscosity and ease of manufacturing. PMID:16922568

  5. Feasibility of Surfactant-Free Supported Emulsion Liquid Membrane Extraction

    NASA Technical Reports Server (NTRS)

    Hu, Shih-Yao B.; Li, Jin; Wiencek, John M.

    2001-01-01

    Supported emulsion liquid membrane (SELM) is an effective means to conduct liquid-liquid extraction. SELM extraction is particularly attractive for separation tasks in the microgravity environment where density difference between the solvent and the internal phase of the emulsion is inconsequential and a stable dispersion can be maintained without surfactant. In this research, dispersed two-phase flow in SELM extraction is modeled using the Lagrangian method. The results show that SELM extraction process in the microgravity environment can be simulated on earth by matching the density of the solvent and the stripping phase. Feasibility of surfactant-free SELM (SFSELM) extraction is assessed by studying the coalescence behavior of the internal phase in the absence of the surfactant. Although the contacting area between the solvent and the internal phase in SFSELM extraction is significantly less than the area provided by regular emulsion due to drop coalescence, it is comparable to the area provided by a typical hollow-fiber membrane. Thus, the stripping process is highly unlikely to become the rate-limiting step in SFSELM extraction. SFSELM remains an effective way to achieve simultaneous extraction and stripping and is able to eliminate the equilibrium limitation in the typical solvent extraction processes. The SFSELM design is similar to the supported liquid membrane design in some aspects.

  6. New Pickering emulsions stabilized by bacterial cellulose nanocrystals.

    PubMed

    Kalashnikova, Irina; Bizot, Hervé; Cathala, Bernard; Capron, Isabelle

    2011-06-21

    We studied oil in water Pickering emulsions stabilized by cellulose nanocrystals obtained by hydrochloric acid hydrolysis of bacterial cellulose. The resulting solid particles, called bacterial cellulose nanocrystals (BCNs), present an elongated shape and low surface charge density, forming a colloidal suspension in water. The BCNs produced proved to stabilize the hexadecane/water interface, promoting monodispersed oil in water droplets around 4 μm in diameter stable for several months. We characterized the emulsion and visualized the particles at the surface of the droplets by scanning electron microscopy (SEM) and calculated the droplet coverage by varying the BCN concentration in the aqueous phase. A 60% coverage limit has been defined, above which very stable, deformable droplets are obtained. The high stability of the more covered droplets was attributed to the particle irreversible adsorption associated with the formation of a 2D network. Due to the sustainability and low environmental impact of cellulose, the BCN based emulsions open opportunities for the development of environmentally friendly new materials.

  7. Some modification of cellulose nanocrystals for functional Pickering emulsions.

    PubMed

    Saidane, Dorra; Perrin, Emilie; Cherhal, Fanch; Guellec, Florian; Capron, Isabelle

    2016-07-28

    Cellulose nanocrystals (CNCs) are negatively charged colloidal particles well known to form highly stable surfactant-free Pickering emulsions. These particles can vary in surface charge density depending on their preparation by acid hydrolysis or applying post-treatments. CNCs with three different surface charge densities were prepared corresponding to 0.08, 0.16 and 0.64 e nm(-2), respectively. Post-treatment might also increase the surface charge density. The well-known TEMPO-mediated oxidation substitutes C6-hydroxyl groups by C6-carboxyl groups on the surface. We report that these different modified CNCs lead to stable oil-in-water emulsions. TEMPO-oxidized CNC might be the basis of further modifications. It is shown that they can, for example, lead to hydrophobic CNCs with a simple method using quaternary ammonium salts that allow producing inverse water-in-oil emulsions. Different from CNC modification before emulsification, modification can be carried out on the droplets after emulsification. This way allows preparing functional capsules according to the layer-by-layer process. As a result, it is demonstrated here the large range of use of these biobased rod-like nanoparticles, extending therefore their potential use to highly sophisticated formulations.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'.

  8. Particle shape anisotropy in pickering emulsions: cubes and peanuts.

    PubMed

    de Folter, Julius W J; Hutter, Eline M; Castillo, Sonja I R; Klop, Kira E; Philipse, Albert P; Kegel, Willem K

    2014-02-01

    We have investigated the effect of particle shape in Pickering emulsions by employing, for the first time, cubic and peanut-shaped particles. The interfacial packing and orientation of anisotropic microparticles are revealed at the single-particle level by direct microscopy observations. The uniform anisotropic hematite microparticles adsorb irreversibly at the oil-water interface in monolayers and form solid-stabilized o/w emulsions via the process of limited coalescence. Emulsions were stable against further coalescence for at least 1 year. We found that cubes assembled at the interface in monolayers with a packing intermediate between hexagonal and cubic and average packing densities of up to 90%. Local domains displayed densities even higher than theoretically achievable for spheres. Cubes exclusively orient parallel with one of their flat sides at the oil-water interface, whereas peanuts preferentially attach parallel with their long side. Those peanut-shaped microparticles assemble in locally ordered, interfacial particle stacks that may interlock. Indications for long-range capillary interactions were not found, and we hypothesize that this is related to the observed stable orientations of cubes and peanuts that marginalize deformations of the interface.

  9. Development of foamed emulsion bioreactor for air pollution control.

    PubMed

    Kan, Eunsung; Deshusses, Marc A

    2003-10-20

    A new type of bioreactor for air pollution control has been developed. The new process relies on an organic-phase emulsion and actively growing pollutant-degrading microorganisms, made into a foam with the air being treated. This new reactor is referred to as a foamed emulsion bioreactor (FEBR). As there is no packing in the reactor, the FEBR is not subject to clogging. Mathematical modeling of the process and proof of concept using a laboratory prototype revealed that the foamed emulsion bioreactor greatly surpasses the performance of existing gas-phase bioreactors. Experimental results showed a toluene elimination capacity as high as 285 g(toluene) m(-3) (reactor) h(-1) with a removal efficiency of 95% at a gas residence time of 15 s and a toluene inlet concentration of 1-1.3 g x m(-3). Oxygen limited the reactor performance at toluene concentration above about 0.7-1.0 g x m(-3); consequently, performance was significantly improved when pure oxygen was added to the contaminated air. The elimination capacity increased from 204 to 408 g x m(-3) h(-1) with >77% toluene removal at toluene inlet concentrations of 2-2.2 g x m(-3). Overall, the results show that the performance of the FEBR far exceeds that of currently used bioreactors for air pollution control.

  10. Preparation and evaluation of minoxidil foamable emu oil emulsion

    PubMed Central

    Shatalebi, M.A.; Rafiei, Y.

    2014-01-01

    The aim of this work was to develop and evaluate a minoxidil foamable emu oil emulsion with the purpose of improving minoxidil permeation into the skin, increasing hair growth, reducing skin irritation, and increasing consumer compliance. Minoxidil was dissolved in a solvent system comprising ethanol: glycerin: lactic acid: water (10:20:5:65). The foamable emulsion was prepared by mixing the oil phase with minoxidil solution using different amount of various emulsifiers. Seventeen formulations were prepared and the most stable foamable emulsion was selected and evaluated for various pharmaceutical parameters such as homogeneity, pH, stability to centrifugal stress, freeze-thaw and foamability. The adopted formulation showed good pharmaceutical characteristics. In vitro release rate of the formulations were evaluated using Franz diffusion cell using phosphate buffer pH 7.4 and ethanol as the receiver medium at sink condition. The release rate of formulations was found to obey Higuchi kinetic model. Experimental animal study was performed to evaluate hair growth potential of the formulation. Different cyclic phases of hair follicles, like anagen, and telogen phases, were determined at one month period. Histological study after treatment with adopted formulation exhibited greater number of hair follicles in anagenic phase (96%) which were higher as compared to marketed 5% minoxidil solution (Pakdaru® 70%) and the control group (42%). From animal study it was concluded that the selected formulation exhibited a significant potency in promoting hair growth in comparison with marketed 5% minoxidil solution Pakdaru®. PMID:25657781

  11. Stabilising emulsion-based colloidal structures with mixed food ingredients.

    PubMed

    Dickinson, Eric

    2013-03-15

    The physical scientist views food as a complex form of soft matter. The complexity has its origin in the numerous ingredients that are typically mixed together and the subtle variations in microstructure and texture induced by thermal and mechanical processing. The colloid science approach to food product formulation is based on the assumption that the major product attributes such as appearance, rheology and physical stability are determined by the spatial distribution and interactions of a small number of generic structural entities (biopolymers, particles, droplets, bubbles, crystals) organised in various kinds of structural arrangements (layers, complexes, aggregates, networks). This review describes some recent advances in this field with reference to three discrete classes of dispersed systems: particle-stabilised emulsions, emulsion gels and aerated emulsions. Particular attention is directed towards explaining the crucial role of the macromolecular ingredients (proteins and polysaccharides) in controlling the formation and stabilisation of the colloidal structures. The ultimate objective of this research is to provide the basic physicochemical insight required for the reliable manufacture of novel structured foods with an appealing taste and texture, whilst incorporating a more healthy set of ingredients than those found in many existing traditional products.

  12. Experimental study of the thermophoretic mobility of a colloidal emulsion

    NASA Astrophysics Data System (ADS)

    Hoyos, Mauricio; van Batten, Charles; Amato, Samuel; Martin, Michel

    1997-11-01

    We have studied the thermophoretic migration of a pharmaceutical oil-in-water emulsion flowing in a Hele-Shaw cell, under the effect of a thermal gradient applied perpendicularly to the flow. Under this strong thermal gradient (several thousands =B0c/cm), a small volume (20 microlitters) of emulsion, migrates toward one wall; simultaneously, a diffusive flow is created in opposite direction to drops migration, leading to the establishment of an equilibrium exponential concentration distribution in the thickness of the cell. The cloud of drops is transported all along the cell by a vector liquid (water) which has a parabolic flow velocity profile. The axial velocity of the droplets depends on their interaction with the thermal field. The parameter determined by the axial sample velocity is the Soret coefficient of the emulsion, defined by the ratio between the thermal diffusion coefficient (thermophoretic mobility) and the particle diffusion coefficient, the last given by the Stokes-Einstein relationship. We have obtained experimentally that the Soret coefficient increases with the size d of droplets as d0.6, while the thermal diffusion coefficient decreases with d as d-0.4. We have also determined by means of a thermogravitational technique that droplets migrate toward the cold wall.

  13. An emulsion polymerization process for soluble and electrically conductive polyaniline

    SciTech Connect

    Kinlen, P.J.; Ding, Y.; Graham, C.R.; Liu, J.; Remsen, E.E.

    1998-07-01

    A new emulsion process has been developed for the direct synthesis of the emeraldine salt of polyaniline (PANI) that is soluble in organic solvents. The process entails forming an emulsion composed of water, a water soluble organic solvent (e.g., 2-butoxyethanol), a water insoluble organic acid (e.g., dinonylnaphthalene sulfonic acid) and aniline. Aniline is protonated by the organic acid to form a salt which partitions into the organic phase. As oxidant (ammonium peroxydisulfate) is added, PANI salt forms in the organic phase and remains soluble. As the reaction proceeds, the reaction mixture changes from an emulsion to a two phase system, the soluble PANI remaining in the organic phase. With dinonylnaphthalene sulfonic acid (DNNSA) as the organic acid, the resulting product is truly soluble in organic solvents such as xylene and toluene (not a dispersion), of high molecular weight (M{sub w} > 22,000), film forming and miscible with many polymers such as polyurethanes, epoxies and phenoxy resins. As cast, the polyaniline film is only moderately conductive, (10{sup {minus}5} S/cm), however treatment of the film with surfactants such as benzyltriethylammonium chloride (BTEAC) or low molecular weight alcohols and ketones such as methanol and acetone increases the conductivity 2--3 orders of magnitude.

  14. Some modification of cellulose nanocrystals for functional Pickering emulsions.

    PubMed

    Saidane, Dorra; Perrin, Emilie; Cherhal, Fanch; Guellec, Florian; Capron, Isabelle

    2016-07-28

    Cellulose nanocrystals (CNCs) are negatively charged colloidal particles well known to form highly stable surfactant-free Pickering emulsions. These particles can vary in surface charge density depending on their preparation by acid hydrolysis or applying post-treatments. CNCs with three different surface charge densities were prepared corresponding to 0.08, 0.16 and 0.64 e nm(-2), respectively. Post-treatment might also increase the surface charge density. The well-known TEMPO-mediated oxidation substitutes C6-hydroxyl groups by C6-carboxyl groups on the surface. We report that these different modified CNCs lead to stable oil-in-water emulsions. TEMPO-oxidized CNC might be the basis of further modifications. It is shown that they can, for example, lead to hydrophobic CNCs with a simple method using quaternary ammonium salts that allow producing inverse water-in-oil emulsions. Different from CNC modification before emulsification, modification can be carried out on the droplets after emulsification. This way allows preparing functional capsules according to the layer-by-layer process. As a result, it is demonstrated here the large range of use of these biobased rod-like nanoparticles, extending therefore their potential use to highly sophisticated formulations.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'. PMID:27298429

  15. Boiling of an emulsion in a yield stress fluid.

    PubMed

    Guéna, Geoffroy; Wang, Ji; d'Espinose, Jean-Baptiste; Lequeux, François; Talini, Laurence

    2010-11-01

    We report the boiling behavior of pentane emulsified in a yield stress fluid, a colloidal clay (Laponite) suspension. We have observed that a superheated state is easily reached: the emulsion, heated more than 50 °C above the alkane boiling point, does not boil. Superheating is made possible by the suppression of heterogeneous nucleation in pentane, resulting from the emulsification process, a phenomenon evidenced decades ago in studies of the superheating of two phase fluids. We have furthermore studied the growth of isolated bubbles nucleated in the emulsion. The rate of increase of the bubble radius with time depends on both the temperature and emulsion volume fraction but, rather unexpectedly, does not depend on the fluid rheology. We show that the bubbles grow by diffusion of the alkane through the aqueous phase between liquid droplets and bubbles, analogously to an Ostwald ripening process. The peculiarity of the process reported here is that a layer depleted in oil droplets forms around the bubble, layer to which the alkane concentration gradient is confined. We successfully describe our experimental results with a simple transfer model.

  16. Impact of pNIPAM microgel size on its ability to stabilize Pickering emulsions.

    PubMed

    Destribats, Mathieu; Eyharts, Mayalen; Lapeyre, Véronique; Sellier, Elisabeth; Varga, Imre; Ravaine, Valérie; Schmitt, Véronique

    2014-02-25

    We study the influence of the particle size on the ability of poly(N-isoprolylacrylamide) microgels to stabilize direct oil-in-water Pickering emulsions. The microgel size is varied from 250 to 760 nm, the cross-linking density being kept constant. The emulsion properties strongly depend on the stabilizer size: increasing the particle size induces an evolution from dispersed drops and fluid emulsions toward strongly adhesive drops and flocculated emulsions. In order to get insight into this dependency, we study how particles adsorb at the interface and we determine the extent of their deformation. We propose a correlation between microgel ability to deform and emulsion macroscopic behavior. Indeed, as the microgels size increases, their internal structure becomes more heterogeneous and so does the polymeric interfacial layer they form. The loss of a uniform dense layer favors bridging between neighboring drops, leading to flocculated and therefore less handleable emulsions.

  17. Pickering emulsions based on cyclodextrins: A smart solution for antifungal azole derivatives topical delivery.

    PubMed

    Leclercq, Loïc; Nardello-Rataj, Véronique

    2016-01-20

    Surfactants are usually used for the preparation of emulsions. Potential drawbacks on the human body or on the environment can be observed for some of them(e.g. skin irritation, hemolysis, protein denaturation, etc.). However, it is possible to use biocompatible emulsifiers such as native cyclodextrins (CDs). The mixture of oil (paraffin oil or isopropyl myristate), water and native CDs results in the formation of Pickering emulsions. The emulsion properties were investigated by ternary phase diagrams elaboration, multiple light scattering, optical and transmission microscopies. The results prove that these Pickering emulsions were very stable against coalescence due to the dense film format the oil/water interface. The rheological behavior has shown that these emulsions remain compatible for topical applications. This kind of emulsions (biocompatibility, stability and surfactant free) has been used to obtain sustainable formulations for antifungal econazole derivatives delivery. Our results prove that these new formulations are at least as active as commercially available formulations.

  18. A simple and low-cost 3d-printed emulsion generator

    NASA Astrophysics Data System (ADS)

    Zhang, J. M.; Aguirre-Pablo, A. A.; Li, E. Q.; Thoroddsen, S. T.

    2015-11-01

    The technique traditionally utilized to fabricate microfluidic emulsion generators, i.e. soft-lithography, is complex and expensive for producing three-dimensional (3D) structures. Here we apply 3D printing technology to fabricate a simple and low-cost 3D printed microfluidic device for emulsion generation without the need for surface treatment on the channel walls. This 3D-printed emulsion generator has been successfully tested over a range of conditions. We also formulate and demonstrate uniform scaling laws for emulsion droplets generated in different regimes for the first time, by incorporating the dynamic contact angle effects during the drop formation. Magnetically responsive microspheres are also produced with our emulsion templates, demonstrating the potential applications of this 3D emulsion generator in material and chemical engineering.

  19. Transport and Retention of Concentrated Oil-in-Water Emulsions in Sandy Porous Media

    NASA Astrophysics Data System (ADS)

    Muller, K.; Esahani, S. G.; Steven, C. C.; Ramsburg, A.

    2015-12-01

    Oil-in-water emulsions are widely employed to promote biotic reduction of contaminants; however, emulsions can also be used to encapsulate and deliver active ingredients required for long-term subsurface treatment. Our research focuses on encapsulating alkalinity-releasing particles in oil-in-water emulsions for sustained control of subsurface pH. Typical characteristics of these emulsions include kinetically stable for >20 hr; 20% soybean oil; 1 g/mL density; 8-10 cP viscosity; and 1.5 μm droplet d50, with emulsions developed for favorable subsurface delivery. The viscosity of the oil-in-water emulsions was found to be a function of oil content. Ultimately we aim to model both emulsion delivery and alkalinity release (from retained emulsion droplets) to provide a description of pH treatment. Emulsion transport and retention was investigated via a series of 1-d column experiments using varying particle size fractions of Ottawa sand. Emulsions were introduced for approximately two pore volumes followed by a flush of background solution (approx. ρ=1 g/mL; μ=1cP). Emulsion breakthrough curves exhibit an early fall on the backside of the breakthrough curve along with tailing. Deposition profiles are found to be hyper-exponential and unaffected by extended periods of background flow. Particle transport models established for dilute suspensions are unable to describe the transport of the concentrated emulsions considered here. Thus, we explore the relative importance of additional processes driving concentrated droplet transport and retention. Focus is placed on evaluating the role of attachment-detachment-straining processes, as well as the influence of mixing from both viscous instabilities and variable water saturation due to deposited mass.

  20. Diazepam submicron emulsions containing soya-bean oil and intended for oral or rectal delivery.

    PubMed

    Gajewska, M; Sznitowska, M; Janicki, S

    2001-03-01

    Physically stable diazepam submicron emulsions were prepared using soya-bean oil. Diazepam concentration 4 mg/ml, suitable for rectal or oral delivery, was achieved in 20% emulsions. Mixture of egg lecithin (1.2%) and poloxamer (2.0%) has been chosen as the most suitable emulsifying agent. Composition of the emulsion may be supplemented with alpha-tocopherol and parabens. However, the system was not stable when either phenylethanol or chlorhexidine gluconate was added. Taste masking agents commonly used as food additives decreased stability of the preparation and were not efficient in elimination of a bitter taste of the drug-loaded emulsions.

  1. Sub-micron alignment for nuclear emulsion plates using low energy electrons caused by radioactive isotopes

    NASA Astrophysics Data System (ADS)

    Miyamoto, S.; Ariga, A.; Fukuda, T.; Kazuyama, M.; Komatsu, M.; Nakano, T.; Niwa, K.; Sato, O.; Takahashi, S.

    2007-06-01

    Nuclear emulsion plates are employed in three-dimensional charged particle detectors that have sub-micron position resolution over 1 m2 with no dead space and no dead time. These detectors are suitable for the study of short-lived particle decays, and direct detection of neutrino interactions of all flavors. Typically emulsion plates are used in a stacked structure. Precise alignment between plates is required for physics analysis. The most accurate alignment method is to use tracks passing through the emulsion plates. The accuracy is about 0.2 μm. However, in an experiment with low track density alignment accuracy decreases to 20 μm because of plate distortion and it becomes more difficult to perform the analysis. This paper describes a new alignment method between emulsion plates by using trajectories of low energy electrons originating from environmental radioactive isotopes. As a trial emulsion plates were exposed to β-rays and γ-rays from K40. The trajectories which passed through emulsion layers were detected by a fully automated emulsion readout system. Using this method, the alignment between emulsion plates is demonstrated to be sub-micron. This method can be applied to many nuclear emulsion experiments. For example, the location of neutrino interaction vertices in the OPERA experiment can benefit from this new technique.

  2. Rheological behavior of water-in-oil emulsions stabilized by hydrophobic bentonite particles.

    PubMed

    Binks, Bernard P; Clint, John H; Whitby, Catherine P

    2005-06-01

    A study of the rheological behavior of water-in-oil emulsions stabilized by hydrophobic bentonite particles is described. Concentrated emulsions were prepared and diluted at constant particle concentration to investigate the effect of drop volume fraction on the viscosity and viscoelastic response of the emulsions. The influence of the structure of the hydrophobic clay particles in the oil has also been studied by using oils in which the clay swells to very different extents. Emulsions prepared from isopropyl myristate, in which the particles do not swell, are increasingly flocculated as the drop volume fraction increases and the viscosity of the emulsions increases accordingly. The concentrated emulsions are viscoelastic and the elastic storage and viscous loss moduli also increase with increasing drop volume fraction. Emulsions prepared from toluene, in which the clay particles swell to form tactoids, are highly structured due to the formation of an integrated network of clay tactoids and drops, and the moduli of the emulsions are significantly larger than those of the emulsions prepared from isopropyl myristate.

  3. A computer system to analyze showers in nuclear emulsions: Center Director's discretionary fund report

    NASA Technical Reports Server (NTRS)

    Meegan, C. A.; Fountain, W. F.; Berry, F. A., Jr.

    1987-01-01

    A system to rapidly digitize data from showers in nuclear emulsions is described. A TV camera views the emulsions though a microscope. The TV output is superimposed on the monitor of a minicomputer. The operator uses the computer's graphics capability to mark the positions of particle tracks. The coordinates of each track are stored on a disk. The computer then predicts the coordinates of each track through successive layers of emulsion. The operator, guided by the predictions, thus tracks and stores the development of the shower. The system provides a significant improvement over purely manual methods of recording shower development in nuclear emulsion stacks.

  4. Development of soy lecithin based novel self-assembled emulsion hydrogels.

    PubMed

    Singh, Vinay K; Pandey, Preeti M; Agarwal, Tarun; Kumar, Dilip; Banerjee, Indranil; Anis, Arfat; Pal, Kunal

    2015-03-01

    The current study reports the development and characterization of soy lecithin based novel self-assembled emulsion hydrogels. Sesame oil was used as the representative oil phase. Emulsion gels were formed when the concentration of soy lecithin was >40% w/w. Metronidazole was used as the model drug for the drug release and the antimicrobial tests. Microscopic study showed the apolar dispersed phase in an aqueous continuum phase, suggesting the formation of emulsion hydrogels. FTIR study indicated the formation of intermolecular hydrogen bonding, whereas, the XRD study indicated predominantly amorphous nature of the emulsion gels. Composition dependent mechanical and drug release properties of the emulsion gels were observed. In-depth analyses of the mechanical studies were done using Ostwald-de Waele power-law, Kohlrausch and Weichert models, whereas, the drug release profiles were modeled using Korsmeyer-Peppas and Peppas-Sahlin models. The mechanical analyses indicated viscoelastic nature of the emulsion gels. The release of the drug from the emulsion gels was diffusion mediated. The drug loaded emulsion gels showed good antimicrobial activity. The biocompatibility test using HaCaT cells (human keratinocytes) suggested biocompatibility of the emulsion gels.

  5. Fabrication and characterization of antioxidant pickering emulsions stabilized by zein/chitosan complex particles (ZCPs).

    PubMed

    Wang, Li-Juan; Hu, Ya-Qiong; Yin, Shou-Wei; Yang, Xiao-Quan; Lai, Fu-Rao; Wang, Si-Qi

    2015-03-11

    Lipid peroxidation in oil-in-water (o/w) emulsions leads to rancidity and carcinogen formation. This work attempted to protect lipid droplets of emulsions from peroxidation via manipulation of the emulsions' interface framework using dual-function zein/CH complex particles (ZCPs). ZCP with intermediate wettability was fabricated via a simple antisolvent approach. Pickering emulsions were produced via a simple and inexpensive shear-induced emulsification technique. ZCP was irreversibly anchored at the oil-water interface to form particle-based network architecture therein, producing ultrastable o/w Pickering emulsions (ZCPEs). ZCPE was not labile to lipid oxidation, evidenced by low lipid hydroperoxides and malondialdehyde levels in the emulsions after thermally accelerated storage. The targeted accumulation of curcumin, a model antioxidant, at the interface was achieved using the ZCP as interfacial vehicle, forming antioxidant shells around dispersed droplets. The oxidative stability of ZCPEs was further improved. Interestingly, no detectable hexanal peak appeared in headspace gas chromatography of the Pickering emulsions. The novel interfacial architecture via the combination of steric hindrance from ZCP-based membrane and interfacial cargo of curcumin endowed the emulsions with favorable oxidative stability. This study opens a promising pathway for producing antioxidant emulsions via the combination of Pickering stabilization mechanism and interfacial delivery of antioxidant.

  6. Pickering-type water-in-oil-in-water multiple emulsions toward multihollow nanocomposite microspheres.

    PubMed

    Maeda, Hayata; Okada, Masahiro; Fujii, Syuji; Nakamura, Yoshinobu; Furuzono, Tsutomu

    2010-09-01

    Multihollow hydroxyapatite (HAp)/poly(L-lactic acid) (PLLA) nanocomposite microspheres were readily fabricated by solvent evaporation from a "Pickering-type" water-in-(dichloromethane solution of PLLA)-in-water multiple emulsion stabilized with HAp nanoparticles. The multiple emulsion was stabilized with the aid of PLLA molecules used as a wettability modifier for HAp nanoparticles, although HAp nanoparticles did not work solely as particulate emulsifiers for Pickering-type emulsions consisting of pure dichloromethane and water. The interaction between PLLA and HAp nanoparticles at the oil-water interfaces plays a crucial role toward the preparation of stable multiple emulsion and multihollow microspheres.

  7. Starch-based Pickering emulsions for topical drug delivery: A QbD approach.

    PubMed

    Marto, J; Gouveia, L; Jorge, I M; Duarte, A; Gonçalves, L M; Silva, S M C; Antunes, F; Pais, A A C C; Oliveira, E; Almeida, A J; Ribeiro, H M

    2015-11-01

    Pickering emulsions are stabilized by solid particles instead of surfactants and have been widely investigated in pharmaceutical and cosmetic fields since they present less adverse effects than the classical emulsions. A quality by design (QbD) approach was applied to the production of w/o emulsions stabilized by starch. A screening design was conducted to identify the critical variables of the formula and the process affecting the critical quality properties of the emulsion (droplet size distribution). The optimization was made by establishing the Design Space, adjusting the concentration of starch and the quantity of the internal aqueous phase. The emulsion production process was, in turn, adjusted by varying the time and speed of stirring, to ensure quality and minimum variability. The stability was also investigated, demonstrating that an increase in starch concentration improves the stability of the emulsion. Rheological and mechanical studies indicated that the viscosity of the emulsions was enhanced by the addition of starch and, to a higher extent, by the presence of different lipids. The developed formulations was considered non-irritant, by an in vitro assay using human cells from skin (Df and HaCat) with the cell viability higher than 90% and, with self-preserving properties. Finally, the QbD approach successfully built quality in Pickering emulsions, allowing the development of hydrophilic drug-loaded emulsions stabilized by starch with desired organoleptic and structural characteristics. The results obtained suggest that these systems are a promising vehicle to be used in products for topical administration.

  8. Color changes in hydrocarbon oil-in-water emulsions caused by Ostwald ripening.

    PubMed

    Weiss, J; McClements, D J

    2001-09-01

    The influence of Ostwald ripening on the optical properties of hydrocarbon oil-in-water emulsions stabilized by sodium dodecyl sulfate was investigated. The droplet size, spectral reflectance, and tristimulus color coordinates (L, a, and b) of a series of n-hexadecane and n-octadecane oil-in-water emulsions were measured in the presence and absence of a water-soluble red dye (FD&C Red No. 40). The droplets grew more rapidly in the emulsion containing n-hexadecane than in the emulsion containing n-octadecane because of the higher solubility of n-hexadecane molecules in the aqueous phase. Ostwald ripening caused appreciable changes in n-hexadecane emulsion spectral reflectance and color L, a, and b values due to the growth of emulsion droplets. L, a, and b color values and spectral reflectances of n-octadecane emulsions did not significantly change during the course of the experiment. The results were explained in terms of Ostwald ripening theory and a previously described light scattering theory. The model enables emulsion manufacturers to predict color changes in oil-in-water emulsions that exhibit transcondensational ripening. PMID:11559140

  9. Starch-based Pickering emulsions for topical drug delivery: A QbD approach.

    PubMed

    Marto, J; Gouveia, L; Jorge, I M; Duarte, A; Gonçalves, L M; Silva, S M C; Antunes, F; Pais, A A C C; Oliveira, E; Almeida, A J; Ribeiro, H M

    2015-11-01

    Pickering emulsions are stabilized by solid particles instead of surfactants and have been widely investigated in pharmaceutical and cosmetic fields since they present less adverse effects than the classical emulsions. A quality by design (QbD) approach was applied to the production of w/o emulsions stabilized by starch. A screening design was conducted to identify the critical variables of the formula and the process affecting the critical quality properties of the emulsion (droplet size distribution). The optimization was made by establishing the Design Space, adjusting the concentration of starch and the quantity of the internal aqueous phase. The emulsion production process was, in turn, adjusted by varying the time and speed of stirring, to ensure quality and minimum variability. The stability was also investigated, demonstrating that an increase in starch concentration improves the stability of the emulsion. Rheological and mechanical studies indicated that the viscosity of the emulsions was enhanced by the addition of starch and, to a higher extent, by the presence of different lipids. The developed formulations was considered non-irritant, by an in vitro assay using human cells from skin (Df and HaCat) with the cell viability higher than 90% and, with self-preserving properties. Finally, the QbD approach successfully built quality in Pickering emulsions, allowing the development of hydrophilic drug-loaded emulsions stabilized by starch with desired organoleptic and structural characteristics. The results obtained suggest that these systems are a promising vehicle to be used in products for topical administration. PMID:26263210

  10. The elimination peculiarities of perfluorocarbon emulsions stabilized with egg yolk phospholipid.

    PubMed

    Putyatina, T K; Aprosin, U D; Afonin, N I

    1994-01-01

    In order to examine the elimination rate of Perfluorodecalin (FDC) emulsions stabilized with different emulsifiers--yolk phospholipid (EYP) and procsanol P-268 (analog of Pluronic F-68)--we performed controlled trials on excretion of FDC in exhaled air, elimination from blood and accumulation in the liver. Adult Wistar rats were injected intravenously with FDC emulsions stabilized with different emulsifiers at a dose of 11.5 g FDC per kg body weight. The concentration of FDC in blood, exhaled air and liver tissue was examined by means of the gas chromatography method. The circulation time in blood for the emulsion stabilized with EYP was much longer comparatively to the emulsion containing the synthetic emulsifier procsanol P-268. The injection of EYP dispersions prolonged the circulation time of lipid-stabilised FDC emulsions. The rate of PFC elimination in exhaled air from such an emulsion and the rate of its accumulation in liver during the initial period after injection are reduced compared to the procsanol-stabilized emulsion. These data are interpreted as the result of a reduction of phagocytic activity of blood monocytes toward the lipid-coated particles of the emulsion. The circulation time of PFC emulsion can be prolonged by using lipid emulsifier and additional injections of EYP dispersion. PMID:7849934

  11. Immunomodulatory and physical effects of phospholipid composition in vaccine adjuvant emulsions.

    PubMed

    Fox, Christopher B; Baldwin, Susan L; Duthie, Malcolm S; Reed, Steven G; Vedvick, Thomas S

    2012-06-01

    Egg phosphatidylcholine is commonly used as an emulsifier in formulations administered parenterally. However, synthetic phosphatidylcholine (PC) emulsifiers are now widely available and may be desirable substitutes for egg-derived phospholipids due to stability, purity, and material source considerations. In earlier work, we demonstrated that a squalene-1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) emulsion provided equivalent physical stability compared to a squalene-egg PC emulsion. In the present manuscript, we evaluate the physical stability of vaccine adjuvant emulsions containing a range of other synthetic phosphatidylcholine emulsifiers. Besides the POPC emulsion, the 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) emulsion showed good particle size and visual stability compared to emulsions made with other synthetic phospholipids. Moreover, comparable immune responses were elicited by squalene emulsions employing various synthetic PC or egg PC emulsifiers in combination with an inactivated influenza vaccine or a recombinant malaria antigen, and these responses were generally enhanced compared to antigen without adjuvant. Therefore, we show that (1) some synthetic PCs (DMPC, POPC, and to a lesser extent 1,2-dioleoyl-sn-glycero-3-phosphocholine) are effective stabilizers of squalene emulsion over a range of storage temperatures while others are not (1,2-distearoyl-sn-glycero-3-phosphocholine, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, and 1,2-dilauroyl-sn-glycero-3-phosphocholine) and (2) the immunogenicity of stable squalene emulsions is similar regardless of PC source. PMID:22415641

  12. Color changes in hydrocarbon oil-in-water emulsions caused by Ostwald ripening.

    PubMed

    Weiss, J; McClements, D J

    2001-09-01

    The influence of Ostwald ripening on the optical properties of hydrocarbon oil-in-water emulsions stabilized by sodium dodecyl sulfate was investigated. The droplet size, spectral reflectance, and tristimulus color coordinates (L, a, and b) of a series of n-hexadecane and n-octadecane oil-in-water emulsions were measured in the presence and absence of a water-soluble red dye (FD&C Red No. 40). The droplets grew more rapidly in the emulsion containing n-hexadecane than in the emulsion containing n-octadecane because of the higher solubility of n-hexadecane molecules in the aqueous phase. Ostwald ripening caused appreciable changes in n-hexadecane emulsion spectral reflectance and color L, a, and b values due to the growth of emulsion droplets. L, a, and b color values and spectral reflectances of n-octadecane emulsions did not significantly change during the course of the experiment. The results were explained in terms of Ostwald ripening theory and a previously described light scattering theory. The model enables emulsion manufacturers to predict color changes in oil-in-water emulsions that exhibit transcondensational ripening.

  13. Rapid Evaluation of Water-in-Oil (w/o) Emulsion Stability by Turbidity Ratio Measurements.

    PubMed

    Song; Jho; Kim; Kim

    2000-10-01

    In this Note, we investigated the turbidity ratio method for the evaluation of water-in-oil emulsion stability. The slope of turbidity ratio of water-in-oil emulsions with time was taken as an index of stability; the higher the slope, the less stable the system. Various factors affecting the stability of emulsion such as HLB of emulsifier, amount of emulsifiers, and water were tested using this technique. The results of the turbidity ratio technique for the evaluation of emulsion stability were well consistent with those obtained by the measurement of phase separation when incubated for 30 days at room temperature. Copyright 2000 Academic Press.

  14. The Effect of Fish Oil-Based Lipid Emulsion and Soybean Oil-Based Lipid Emulsion on Cholestasis Associated with Long-Term Parenteral Nutrition in Premature Infants

    PubMed Central

    Wang, Leilei; Zhang, Jing; Gao, Jiejin; Qian, Yan; Ling, Ya

    2016-01-01

    Purpose. To retrospectively study the effect of fish oil-based lipid emulsion and soybean oil-based lipid emulsion on cholestasis associated with long-term parenteral nutrition in premature infants. Methods. Soybean oil-based lipid emulsion and fish oil-based lipid emulsion had been applied in our neonatology department clinically between 2010 and 2014. There were 61 qualified premature infants included in this study and divided into two groups. Soybean oil group was made up of 32 premature infants, while fish oil group was made up of 29 premature infants. Analysis was made on the gender, feeding intolerance, infection history, birth weight, gestational age, duration of parenteral nutrition, total dosage of amino acid, age at which feeding began, usage of lipid emulsions, and incidence of cholestasis between the two groups. Results. There were no statistical differences in terms of gender, feeding intolerance, infection history, birth weight, gestational age, duration of parenteral nutrition, total dosage of amino acid, and age at which feeding began. Besides, total incidence of cholestasis was 21.3%, and the days of life of occurrence of cholestasis were 53 ± 5.0 days. Incidence of cholestasis had no statistical difference in the two groups. Conclusion. This study did not find the different role of fish oil-based lipid emulsions and soybean oil-based lipid emulsions in cholestasis associated with long-term parenteral nutrition in premature infants. PMID:27110237

  15. The Effect of Fish Oil-Based Lipid Emulsion and Soybean Oil-Based Lipid Emulsion on Cholestasis Associated with Long-Term Parenteral Nutrition in Premature Infants.

    PubMed

    Wang, Leilei; Zhang, Jing; Gao, Jiejin; Qian, Yan; Ling, Ya

    2016-01-01

    Purpose. To retrospectively study the effect of fish oil-based lipid emulsion and soybean oil-based lipid emulsion on cholestasis associated with long-term parenteral nutrition in premature infants. Methods. Soybean oil-based lipid emulsion and fish oil-based lipid emulsion had been applied in our neonatology department clinically between 2010 and 2014. There were 61 qualified premature infants included in this study and divided into two groups. Soybean oil group was made up of 32 premature infants, while fish oil group was made up of 29 premature infants. Analysis was made on the gender, feeding intolerance, infection history, birth weight, gestational age, duration of parenteral nutrition, total dosage of amino acid, age at which feeding began, usage of lipid emulsions, and incidence of cholestasis between the two groups. Results. There were no statistical differences in terms of gender, feeding intolerance, infection history, birth weight, gestational age, duration of parenteral nutrition, total dosage of amino acid, and age at which feeding began. Besides, total incidence of cholestasis was 21.3%, and the days of life of occurrence of cholestasis were 53 ± 5.0 days. Incidence of cholestasis had no statistical difference in the two groups. Conclusion. This study did not find the different role of fish oil-based lipid emulsions and soybean oil-based lipid emulsions in cholestasis associated with long-term parenteral nutrition in premature infants.

  16. Oxidation-Responsive and "Clickable" Poly(ethylene glycol) via Copolymerization of 2-(Methylthio)ethyl Glycidyl Ether.

    PubMed

    Herzberger, Jana; Fischer, Karl; Leibig, Daniel; Bros, Matthias; Thiermann, Raphael; Frey, Holger

    2016-07-27

    Poly(ethylene glycol) (PEG) is a widely used biocompatible polymer. We describe a novel epoxide monomer with methyl-thioether moiety, 2-(methylthio)ethyl glycidyl ether (MTEGE), which enables the synthesis of well-defined thioether-functional poly(ethylene glycol). Random and block mPEG-b-PMTEGE copolymers (Mw/Mn = 1.05-1.17) were obtained via anionic ring opening polymerization (AROP) with molecular weights ranging from 5 600 to 12 000 g·mol(-1). The statistical copolymerization of MTEGE with ethylene oxide results in a random microstructure (rEO = 0.92 ± 0.02 and rMTEG E = 1.06 ± 0.02), which was confirmed by in situ (1)H NMR kinetic studies. The random copolymers are thermoresponsive in aqueous solution, with a wide range of tunable transition temperatures of 88 to 28 °C. In contrast, mPEG-b-PMTEGE block copolymers formed well-defined micelles (Rh ≈ 9-15 nm) in water, studied by detailed light scattering (DLS and SLS). Intriguingly, the thioether moieties of MTEGE can be selectively oxidized into sulfoxide units, leading to full disassembly of the micelles, as confirmed by detection of pure unimers (DLS and SLS). Oxidation-responsive release of encapsulated Nile Red demonstrates the potential of these micelles as redox-responsive nanocarriers. MTT assays showed only minor effects of the thioethers and their oxidized derivatives on the cellular metabolism of WEHI-164 and HEK-293T cell lines (1-1000 μg·mL(-1)). Further, sulfonium PEG polyelectrolytes can be obtained via alkylation or alkoxylation of MTEGE, providing access to a large variety of functional groups at the charged sulfur atom. PMID:27375132

  17. RAFT Dispersion Alternating Copolymerization of Styrene with N-Phenylmaleimide: Morphology Control and Application as an Aqueous Foam Stabilizer

    PubMed Central

    2016-01-01

    We report a new nonaqueous polymerization-induced self-assembly (PISA) formulation based on the reversible addition–fragmentation chain transfer (RAFT) dispersion alternating copolymerization of styrene with N-phenylmaleimide using a nonionic poly(N,N-dimethylacrylamide) stabilizer in a 50/50 w/w ethanol/methyl ethyl ketone (MEK) mixture. The MEK cosolvent is significantly less toxic than the 1,4-dioxane cosolvent reported previously [YangP.; Macromolecules2013, 46, 8545−8556]. The core-forming alternating copolymer block has a relatively high glass transition temperature (Tg), which leads to vesicular morphologies being observed during PISA, as well as the more typical sphere and worm phases. Each of these copolymer morphologies has been characterized by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) studies. TEM studies reveal micrometer-sized elliptical particles with internal structure, with SAXS analysis suggesting an oligolamellar vesicle morphology. This structure differs from that previously reported for a closely related PISA formulation utilizing a poly(methacrylic acid) stabilizer block for which unilamellar platelet-like particles are observed by TEM and SAXS. This suggests that interlamellar interactions are governed by the nature of the steric stabilizer layer. Moreover, using the MEK cosolvent also enables access to a unilamellar vesicular morphology, despite the high Tg of the alternating copolymer core-forming block. This was achieved by simply conducting the PISA synthesis at a higher temperature for a longer reaction time (80 °C for 24 h). Presumably, MEK solvates the core-forming block more than the previously utilized 1,4-dioxane cosolvent, which leads to greater chain mobility. Finally, preliminary experiments indicate that the worms are much more efficient stabilizers for aqueous foams than either the spheres or the oligolamellar elliptical vesicles.

  18. RAFT Dispersion Alternating Copolymerization of Styrene with N-Phenylmaleimide: Morphology Control and Application as an Aqueous Foam Stabilizer

    PubMed Central

    2016-01-01

    We report a new nonaqueous polymerization-induced self-assembly (PISA) formulation based on the reversible addition–fragmentation chain transfer (RAFT) dispersion alternating copolymerization of styrene with N-phenylmaleimide using a nonionic poly(N,N-dimethylacrylamide) stabilizer in a 50/50 w/w ethanol/methyl ethyl ketone (MEK) mixture. The MEK cosolvent is significantly less toxic than the 1,4-dioxane cosolvent reported previously [YangP.; Macromolecules2013, 46, 8545−8556]. The core-forming alternating copolymer block has a relatively high glass transition temperature (Tg), which leads to vesicular morphologies being observed during PISA, as well as the more typical sphere and worm phases. Each of these copolymer morphologies has been characterized by transmission electron microscopy (TEM) and small-angle X-ray scattering (SAXS) studies. TEM studies reveal micrometer-sized elliptical particles with internal structure, with SAXS analysis suggesting an oligolamellar vesicle morphology. This structure differs from that previously reported for a closely related PISA formulation utilizing a poly(methacrylic acid) stabilizer block for which unilamellar platelet-like particles are observed by TEM and SAXS. This suggests that interlamellar interactions are governed by the nature of the steric stabilizer layer. Moreover, using the MEK cosolvent also enables access to a unilamellar vesicular morphology, despite the high Tg of the alternating copolymer core-forming block. This was achieved by simply conducting the PISA synthesis at a higher temperature for a longer reaction time (80 °C for 24 h). Presumably, MEK solvates the core-forming block more than the previously utilized 1,4-dioxane cosolvent, which leads to greater chain mobility. Finally, preliminary experiments indicate that the worms are much more efficient stabilizers for aqueous foams than either the spheres or the oligolamellar elliptical vesicles. PMID:27708458

  19. Enzymatic copolymerization alters the structure of unpolymerized mixtures of the biomimetic monomers: the amphiphilic decyl ester of L-tyrosine and L-tyrosineamide--an AFM investigation of nano- to micrometer-scale structure differences.

    PubMed

    Marx, Kenneth A; Lee, Jun S; Sung, Changmo

    2004-01-01

    Previously, we have shown that the amphiphilic decyl esters of both D- and L-tyrosine (DELT) self-assemble in aqueous solution above their critical micelle concentration values to form long rodlike structures that can be enzymatically polymerized. In the current study, we have examined the self-assembled structures of unpolymerized and enzymatically (horseradish peroxidase) copolymerized 1:1 molar mixtures of DELT with the nonamphiphilic comonomer L-tyrosineamide. The structures were examined following adsorption to gold-coated mica surfaces using optical microscopy and scanning electron microscopy, but primarily noncontact atomic force microscopy. Both unpolymerized and copolymerized 1:1 comonomer mixture aggregates produced amorphous to spherical shaped structures, exhibiting increased flexibility that contrasted with our previous observations of the more highly ordered long rodlike structures seen with the pure DELT. The unpolymerized comonomer aggregates were amorphous and of varying size. Interestingly, they contained occasional novel structures-smooth, sharp, nipplelike features that rose hundreds of nanometers above the smooth aggregate surface. However, upon enzymatic copolymerization, the structures are altered, forming nearly hemispherical aggregates in contact with each other on the surface. These structures possessed diameters of 1.51 +/- 0.24 microm. The copolymerized structures lacked any evidence of the sharp nipplelike features observed in the unpolymerized sample, but they did exhibit nanometer-scale detailed surface features, indicative of a higher degree of internal organization. The measured surface roughness of the copolymerized comonomer mixture was more than 10 times greater than the surface roughness of the unpolymerized comonomer mixture.

  20. 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.

  1. Stabilization of Pickering Emulsions with Oppositely Charged Latex Particles: Influence of Various Parameters and Particle Arrangement around Droplets.

    PubMed

    Nallamilli, Trivikram; Binks, Bernard P; Mani, Ethayaraja; Basavaraj, Madivala G

    2015-10-20

    In this study we explore the fundamental aspects of Pickering emulsions stabilized by oppositely charged particles. Using oppositely charged latex particles as a model system, Pickering emulsions with good long-term stability can be obtained without the need for any electrolyte. The effects of parameters like oil to water ratio, mixed particle composition, and pH on emulsion type and stability are explored and linked to the behavior of the aqueous particle dispersion prior to emulsification. The particle composition is found to affect the formation of emulsions, viz., stable emulsions were obtained close to a particle number ratio of 1:1, and no emulsion was formed with either positively or negatively charged particles alone. The emulsions in particle mixtures exhibited phase inversion from oil-in-water to water-in-oil beyond an oil volume fraction of 0.8. Morphological features of emulsion droplets in terms of particle arrangement on the droplets are discussed.

  2. Swelling properties of copolymeric hydrogels of poly(ethylene glycol) monomethacrylate and monoesters of itaconic acid for use in drug delivery.

    PubMed

    Teijón, César; Guerrero, Sandra; Olmo, Rosa; Teijón, José M; Blanco, M Dolores

    2009-11-01

    Copolymeric hydrogels of poly(ethylene glycol) monomethacrylate (PEGMA) (P) have been synthesized for use in drug-delivery. New copolymeric hydrogels were prepared by free radical solution polymerization of PEGMA and monomethyl itaconate (MMI) or monoethyl itaconate (MEI), using ethyleneglycol dimethacrylate and tetraethyleneglycol dimethacrylate, respectively, as cross-linkers. The effect of copolymer composition on swelling behavior, thermal decomposition and drug release was studied. Three compositions of each copolymer were studied: 70P/30MMI (or MEI), 80P/20MMI (or MEI) and 90P/10MMI (or MEI). The largest equilibrium swelling degree was observed in gels containing the highest content of MMI or MEI (84.22 +/- 0.22 wt % for 70P/30MEI; 79.56 +/- 0.64 wt % for 70P/30MMI). The swelling process was in accordance with Fick's Second Law. Methotrexate (MTX), an anticancer agent used in the treatment of different hyperproliferative epithelial diseases, was chosen to be loaded in the gels. The drug was included by immersion of the copolymeric disks in an aqueous solution of the drug. The amount of MTX in the xerogels was between 5.34 +/- 0.06 mg MTX/g (90P/10MMI) and 14.94 +/- 0.91 mg MTX/g (80P/20MEI). Two stages of thermal degradation for unloaded and MTX-loaded gels were determined; the presence of the drug in the polymeric matrices decreased the temperature of the first stage of thermal degradation. MTX release was also in accordance with Fick's Second Law. The length of total drug release (340 +/- 30 min-1502 +/- 81 min) could be modulated as a function of the comonomer composition of the hydrogel.

  3. CO2/ethylene oxide copolymerization and ligand variation for a highly active salen-cobalt(III) complex tethering 4 quaternary ammonium salts.

    PubMed

    Jeon, Jong Yeob; Lee, Jung Jae; Varghese, Jobi Kodiyan; Na, Sung Jae; Sujith, S; Go, Min Jeong; Lee, Junseong; Ok, Myung-Ahn; Lee, Bun Yeoul

    2013-07-01

    A cobalt(III) complex (1) of a salcy-type ligand tethering 4 quaternary ammonium salts, which is thought to act as a highly active catalyst for CO2/propylene oxide (PO) copolymerization, also shows high activity (TOF, 25,900 h(-1); TON, 518,000; 2.72 kg polymer per g cat) and selectivity (>98%) for CO2/ethylene oxide (EO) copolymerization that results in high-molecular-weight polymers (M(n), 200,000-300,000) that have strictly alternating repeating units. The related cobalt(III) complexes 11-14 were prepared through variations of the ligand framework of 1 by replacing the trans-1,2-diaminocyclohexane unit with 2,2-dimethyl-1,3-propanediamine, trans-1,2-diaminocyclopentane, or 1,1'-binaphthyl-2,2'-diamine or by replacing the aldimine bond with ketimine. These ligand frameworks are thought to favour the formation of the cis-β configuration in complexation, and the formation of the cis-β configuration in 11-14 was confirmed through NMR studies or X-ray crystallographic studies of model complexes not bearing the quaternary ammonium salts. Complexes 11, 13, and 14, which adopt the cis-β configuration even in DMSO did not show any activity for CO2/PO copolymerization. Complex 12, which was constructed with trans-1,2-diaminocyclopentane and fluctuated in DMSO between the coordination and de-coordination of the acetate ligand as observed for 1, showed fairly high activity (TOF, 12,400 h(-1)). This fluctuating behaviour may play a role in polymerization. However, complex 12 did not compete with 1 in terms of activity, selectivity, and the catalyst cost.

  4. Factors governing partial coalescence in oil-in-water emulsions.

    PubMed

    Fredrick, Eveline; Walstra, Pieter; Dewettinck, Koen

    2010-01-15

    The consequences of the instability mechanism partial coalescence in oil-in-water food emulsions show a discrepancy. On the one hand, it needs to be avoided in order to achieve an extended shelf life in food products like sauces, creams and several milk products. On the other hand, during the manufacturing of products like ice cream, butter and whipped toppings partial coalescence is required to achieve the desired product properties. It contributes to the structure formation, the physicochemical properties (stability, firmness,...) and the sensory perception, like fattiness and creaminess of the final food products. This review critically summarises the findings of partial coalescence in oil-in-water emulsions in order to provide insight in how to enhance and retard it. Next to the pioneering work, a large set of experimental results of more recent work is discussed. First, the general mechanism of partial coalescence is considered and a distinction is made between partial and 'true' coalescence. The main differences are: the required solid particles in the dispersed oil phase, the formation of irregular clusters and the increased aggregation rate. Second, the kinetics of partial coalescence is discussed. In more detail, potential parameters affecting the rate of partial coalescence are considered by means of the encounter frequency and capture efficiency of the fat globules. The flow conditions, the fat volume fraction and the physicochemical properties of continuous aqueous phase affect both the encounter frequency and capture efficiency while the actual temperature, temperature history and the composition and formulation of the emulsion mainly affect the capture efficiency. PMID:19913777

  5. Sterically (un)encumbered mer-tridentate N-heterocyclic carbene complexes of titanium(iv) for the copolymerization of cyclohexene oxide with CO2.

    PubMed

    Hessevik, Julie; Lalrempuia, Ralte; Nsiri, Hajar; Törnroos, Karl W; Jensen, Vidar R; Le Roux, Erwan

    2016-10-01

    Titanium(iv) complexes bearing an unsubstituted tridentate bis(phenolate) N-heterocyclic carbene (NHC) were synthesized and structurally identified. While sterically unencumbered NHC-Ti(iv) complexes bearing chloro and alkoxy co-ligands tend to dimerize in solution and in solid-state, the use of a bulky aryloxy as co-ligand favors the monomeric species. Upon activation by onium salts, all these complexes were found to be highly selective towards the copolymerization of cyclohexene oxide (CHO) with CO2 under mild conditions (PCO2 < 1 bar), albeit the sterically unencumbered NHC-Ti(iv) complexes are less stable and active than their structural analogues bearing bulkier substituents.

  6. Assembly of microspheres with polymers by evaporating emulsion droplets

    NASA Astrophysics Data System (ADS)

    Lin, Keng-Hui; Lai, Liang-Jie; Chang, Chih-Chung; Chen, Hui

    2008-10-01

    We study the packing of colloidal microspheres mixed with polymers in oil-in-water emulsion droplets by evaporation. The addition of polymers produces non-unique configurations of final clusters when the number of particles N inside the droplet is larger than 4. The cluster configurations are classified into three categories based on symmetry. Stablized colloidal clusters of spherical packings are observed. Our observations on packing process suggest the mechanisms which cause different and nonunique structures. The osmotic pressure and the interparticle interaction due to polymers changes the force balance between microspheres and result in different structures.

  7. Size Limit for Particle-Stabilized Emulsion Droplets under Gravity

    NASA Astrophysics Data System (ADS)

    Tavacoli, J. W.; Katgert, G.; Kim, E. G.; Cates, M. E.; Clegg, P. S.

    2012-06-01

    We demonstrate that emulsion droplets stabilized by interfacial particles become unstable beyond a size threshold set by gravity. This holds not only for colloids but also for supracolloidal glass beads, using which we directly observe the ejection of particles near the droplet base. The number of particles acting together in these ejection events decreases with time until a stable acornlike configuration is reached. Stability occurs when the weight of all remaining particles is less than the interfacial binding force of one particle. We also show the importance of the curvature of the droplet surface in promoting particle ejection.

  8. Electrohydrodynamic deformation and interaction of a pair of emulsion drops

    NASA Technical Reports Server (NTRS)

    Baygents, James C.

    1994-01-01

    The response of a pair of emulsion drops to the imposition of a uniform electric field is examined. The case studied is that of equal-sized drops whose line of centers is parallel to the axis of the applied field. A new boundary integral solution to the governing equations of the leaky dielectric model is developed; the formulation accounts for the electrostatic and hydrodynamic interactions between the drops, as well as their deformations. Numerical calculations show that, after an initial transient during which the drops primarily deform, the pair drift slowly together due to their electrostatic interactions.

  9. Acoustically aided coalescence of droplets in aqueous emulsions

    NASA Astrophysics Data System (ADS)

    Pangu, Gautam D.

    An acoustic-field assisted process intended to recover the oil phase from aqueous emulsions has been previously developed. It applies a resonant ultrasonic wavefield to the emulsion flowing through a rectangular chamber. The oil droplets migrate to pressure antinodes of the standing wave-field. Rapid coalescence and plating out of droplets on the internal surfaces of the chamber occurs. To obtain a fundamental understanding of the bulk coalescence of droplets away from any solid surface in acoustic field, a microscopic mathematical model was developed that predicts the relative trajectory of a pair of droplets in an acoustic field by considering pertinent body forces and interdroplet effects. This trajectory analysis was used to compute the rate of volume cleared by the coalescence of different droplet pairs as a function of various operating conditions. The results of the droplet pair model were used as a basis to develop a global model for coalescence rates. The expressions for volume cleared by coalescence of different droplet pairs were incorporated into standard population balance equations to determine the rate of collisions of different droplet pairs. This analysis led to the formulation of a predictive model that could track evolution of drop sizes in a given droplet population coalescing in an acoustic field. The droplet pair model was validated by designing an experimental system to visualize the interaction between two coalescing droplets in an emulsion subjected to a standing acoustic field. The experimentally observed trajectories were compared with those determined by the droplet-pair model. The predicted and observed trajectories matched reasonably well without any model parameter adjustment. The match between relative trajectories predicted by the model and those observed experimentally was further improved via adjustments in the energy density values used in the model. The predictions of the global model were validated by experimentally tracking

  10. Evidence for Newton Black Films between Adhesive Emulsion Droplets

    NASA Astrophysics Data System (ADS)

    Poulin, Philippe; Nallet, Frédéric; Cabane, Bernard; Bibette, Jérôme

    1996-10-01

    A soap film (made of two air/water interfaces covered by surfactant) may turn into a so-called Newton black film (NBF) which essentially consists in a surfactant bilayer. Oil-in-water emulsion droplets covered with surfactant (oil/water interfaces) may become adhesive in similar conditions. We show by analyzing the neutron scattering pattern from a collection of submicronic oil-in-water adhesive droplets that the thin film that forms between them is structurally identical to the NBF. As a consequence, the formation of NBF is a general property of ionic surfactants.

  11. The microenvironment of double emulsions in rectangular microchannels.

    PubMed

    Ma, Shaohua; Sherwood, Joseph M; Huck, Wilhelm T S; Balabani, Stavroula

    2015-05-21

    The flow environment in inner cores of water-in-oil-in-water (w/o/w) microfluidic double emulsions has a significant impact on industrial applications of such systems. For example, in the case of shear sensitive cells compartmentalised in the cores, high shear conditions may be deleterious. This study reports on the flow characteristics of w/o/w inner cores in comparison to those in single water-in-oil (w/o) microdroplets of equal size moving in the same microchannel, resolved by means of micro-particle image velocimetry (μPIV). The multiphase flow system employed in the study had a viscosity ratio, λ, between aqueous and oil phase of the order of unity (λ = 0.78) and both single droplets and inner cores of double emulsions filled the channel. This configuration resulted in a weak recirculating flow inside the w/o single droplet: the measured flow field exhibited a uniform low velocity flow field in the central region surrounded by small regions of reversed flow near the channel walls. This flow topology was maintained in the inner cores of w/o/w double emulsions for intermediate capillary numbers (Ca) ranging from 10(-3) to 10(-2), and core morphologies varying from large plugs to pancake cores. The core morphology affected the magnitude and distribution of the velocity in the droplets. The similarity in the flow topology resulted from the fact that inner cores were located at the back of the outer droplet in such a way that inner and outer interfaces were in contact for over half of core surface area and separated only by a thin lubricating film. Both single droplets and inner cores exhibited a narrow shear rate distribution characterised by small regions of maximum shear confined near the channel walls. Shear rate magnitude values were found to be an order of magnitude lower than those in the channel and hence capable of reducing stresses in flow cytometry to far below reported values for cell damage. Hence, it can be concluded that double emulsions are

  12. Preparation of drug nanoparticles by emulsion evaporation method

    NASA Astrophysics Data System (ADS)

    Hoa, Le Thi Mai; Chi, Nguyen Tai; Triet, Nguyen Minh; Thanh Nhan, Le Ngoc; Mau Chien, Dang

    2009-09-01

    Polymeric drug nanoparticles were prepared by emulsion solvent evaporation method. In this study, prepared the polymeric drug nanoparticles consist of ketoprofen and Eudragit E 100. The morphology structure was investigated by scanning electron microscopy (SEM). The interactions between the drug and polymer were investigated by Fourier transform infrared spectroscopy (FTIR). The size distribution was measured by means of Dynamic Light Scattering. The nanoparticles have an average size of about 150 nm. The incorporation ability of drugs in the polymeric nanoparticles depended on the integration between polymer and drug as well as the glass transition temperature of the polymer.

  13. Size limit for particle-stabilized emulsion droplets under gravity.

    PubMed

    Tavacoli, J W; Katgert, G; Kim, E G; Cates, M E; Clegg, P S

    2012-06-29

    We demonstrate that emulsion droplets stabilized by interfacial particles become unstable beyond a size threshold set by gravity. This holds not only for colloids but also for supracolloidal glass beads, using which we directly observe the ejection of particles near the droplet base. The number of particles acting together in these ejection events decreases with time until a stable acornlike configuration is reached. Stability occurs when the weight of all remaining particles is less than the interfacial binding force of one particle. We also show the importance of the curvature of the droplet surface in promoting particle ejection.

  14. Repackaging of Intravenous Fat Emulsions: A Clinical Conundrum.

    PubMed

    Cober, M Petrea

    2016-10-01

    To accommodate small fluid volumes, repackaging of intravenous fat emulsions (IVFEs) is frequently performed in institutions providing parenteral nutrition to neonates and smaller pediatric patients. However, some consider this an unsafe practice. Concerns for potential administration errors leading to an overdose of IVFEs are weighed against the potential for microbial contamination from the repackaging process. The clinician providing pediatric nutrition support should tailor repackaging practices to ensure patient safety and quality. This discussion aims to describe the strengths and limitations surrounding IVFE repackaging to provide guidance regarding the practice.

  15. Self-Diffusion of Drops in a Dilute Sheared Emulsion

    NASA Technical Reports Server (NTRS)

    Loewenberg, Michael; Hinch, E. J.

    1996-01-01

    Self-diffusion coefficients that describe cross-flow migration of non-Brownian drops in a dilute sheared emulsion were obtained by trajectory calculations. A boundary integral formulation was used to describe pairwise interactions between deformable drops; interactions between undeformed drops were described with mobility functions for spherical drops. The results indicate that drops have large anisotropic self-diffusivities which depend strongly on the drop viscosity and modestly on the shear-rate. Pairwise interactions between drops in shear-flow do not appreciably promote drop breakup.

  16. Mango butter emulsion gels as cocoa butter equivalents: physical, thermal, and mechanical analyses.

    PubMed

    Sagiri, Sai S; Sharma, Vijeta; Basak, Piyali; Pal, Kunal

    2014-11-26

    The search for cocoa butter equivalents in food and pharmaceutical industries has been gaining importance. In the present study, mango butter was explored as cocoa butter equivalent. Aqueous gelatin solution (20% w/w) containing cocoa butter and mango butter water-in-oil (fat) type emulsion gels were prepared by hot emulsification method. XRD and DSC melting profiles suggested the presence of unstable polymorphic forms (α and β') of fats in the emulsion gels. The crystal size and solid fat content analyses suggested that the presence of aqueous phase might have hindered the transformation of unstable polymorphic forms to stable polymorphic form (β) in the emulsion gels. Fat crystals in the emulsion gels were formed by instantaneous nucleation via either uni- or bidimensional growth (Avrami analysis). The viscoelastic nature of the emulsion gels was evaluated by modified Peleg's analysis (stress relaxation study). Results inferred that the physical, thermal, and mechanical properties of mango butter emulsion gels are comparable to those of cocoa butter emulsion gels. On the basis of preliminary studies, it was suggested that the mango butter emulsion gels may have potential to be used as cocoa butter equivalents. PMID:25363450

  17. Lipid nano/submicron emulsions as vehicles for topical flurbiprofen delivery.

    PubMed

    Fang, Jia-You; Leu, Yann-Lii; Chang, Chia-Chun; Lin, Chia-Hsuan; Tsai, Yi-Hung

    2004-01-01

    The application of lipid nano/submicron emulsions as topical drug carrier systems for the percutaneous absorption of flurbiprofen was investigated. The lipid emulsions were made up of isopropyl myristate (IPM), soybean oil, or coconut oil as the oil phase, egg lecithin as the predominant emulsifier, and double-distilled water as the external phase. Stearylamine (SA) and deoxycholic acid (DA) also were used to produce positively and negatively charged emulsions. To evaluate the physicochemical properties of the lipid emulsions, particle size by laser light scattering, the image of atomic force microscopy, and relaxation time values by Nuclear Magnetic Resonance (NMR) were determined. The in vitro permeation data showed that incorporation of SA significantly reduced the topical delivery of flurbiprofen. On the other hand, incorporation of DA exhibited no or a negligible effect on drug permeation. Enhancement of drug absorption was observed when adding oleic acid as part of the oil phase. The in vivo topical application of flurbiprofen from selected lipid emulsions showed a similar trend to the in vitro status. Furthermore, the intersubject variability was considerably reduced by lipid emulsions than by aqueous suspensions in both the in vitro and in vivo experiments. The irritant profiles of lipid emulsions showed that IPM elicited higher irritation than soybean oil. The incorporation of oleic acid also produced skin disruption. The results in the present study suggest the feasibility of lipid emulsions for the topical delivery of flurbiprofen.

  18. Cross-linking oppositely charged oil-in-water emulsions to enhance heteroaggregate stability.

    PubMed

    Maier, Christiane; Oechsle, Anja M; Weiss, Jochen

    2015-11-01

    The formation and subsequent enzymatic and chemical cross-linking of heteroaggregates from oppositely charged oil-in-water (O/W) emulsions was investigated. For this purpose, 10% (w/w) oil-in-water emulsions (d43<1 μm) were prepared at pH 4 using a positively charged emulsifier (Nα-lauroyl-L-arginine ethyl ester (LAE), cold water fish gelatin, or whey protein isolate) or a negatively charged one (sugar beet pectin or Quillaja saponins). The oppositely charged emulsions were then combined at a volume ratio of 1:1 and treated with laccase or glutaraldehyde in order to further stabilize the electrostatically attached aggregates by covalently cross-linking the oppositely charged membranes. Emulsions and heteroaggregates were characterized by their rheological properties, their surface charge, particle size distribution, and microstructure using dynamic and static light scattering as well as confocal laser scanning microscopy. Prior to cross-linking, the emulsifiers' stabilization mechanism were found to greatly influence the formation of heteroaggregates. Laccase treatment (1.34 mU/mL) increased aggregate expansion by ca. 30% for the combined emulsions stabilized by Quillaja saponins/whey protein isolate, while combined Quillaja saponins/fish gelatin stabilized emulsions remained unaffected. When combined emulsions were treated with 50mM glutaraldehyde, aggregate size significantly increased 2- and 3-fold, respectively. Thus, our study provides novel insights into the enzymatic and chemical cross-linking of heteroaggregates composed of oppositely charged O/W emulsions.

  19. 78 FR 58318 - Clinical Trial Design for Intravenous Fat Emulsion Products; Public Workshop

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-23

    ... HUMAN SERVICES Food and Drug Administration Clinical Trial Design for Intravenous Fat Emulsion Products... ``Clinical Trial Design for Intravenous Fat Emulsion Products.'' This workshop will provide a forum to discuss trial design of clinical trials intended to support registration of intravenous fat...

  20. Optimization of folic acid nano-emulsification and encapsulation by maltodextrin-whey protein double emulsions.

    PubMed

    Assadpour, Elham; Maghsoudlou, Yahya; Jafari, Seid-Mahdi; Ghorbani, Mohammad; Aalami, Mehran

    2016-05-01

    Due to susceptibility of folic acid like many other vitamins to environmental and processing conditions, it is necessary to protect it by highly efficient methods such as micro/nano-encapsulation. Our aim was to prepare and optimize real water in oil nano-emulsions containing folic acid by a low energy (spontaneous) emulsification technique so that the final product could be encapsulated within maltodextrin-whey protein double emulsions. A non ionic surfactant (Span 80) was used for making nano-emulsions at three dispersed phase/surfactant ratios of 0.2, 0.6, and 1.0. Folic acid content was 1.0, 2.0, and 3.0mg/mL of dispersed phase by a volume fraction of 5.0, 8.5, and 12%. The final optimum nano-emulsion formulation with 12% dispersed phase, a water to surfactant ratio of 0.9 and folic acid content of 3mg/mL in dispersed phase was encapsulated within maltodextrin-whey protein double emulsions. It was found that the emulsification time for preparing nano-emulsions was between 4 to 16 h based on formulation variables. Droplet size decreased at higher surfactant contents and final nano-emulsions had a droplet size<100 nm. Shear viscosity was higher for those formulations containing more surfactant. Our results revealed that spontaneous method could be used successfully for preparing stable W/O nano-emulsions containing folic acid. PMID:26806649

  1. Development and characterization of a emulsions containing purple rice bran and brown rice oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aims of this study were to characterize purple rice bran oil (PRBO) as extracted from the bran, and to produce and characterize a nano-emulsion containing purple rice bran oil. An emulsion was prepared using PRBO (10%), sodium caseinate (5%) and water (85%). The mixture was sonicated followed ...

  2. Impact of parenteral lipid emulsions on metabolomic phenotype in preterm TPN-fed piglets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lipids in parenteral nutrition provide essential fatty acids and are a major source of energy for hospitalized neonates. Intralipid (IL) is the only approved lipid emulsion in the US, but new generation emulsions include Omegaven (OV) and SMOFlipid (SL). There are no studies describing the metabolit...

  3. Impact of parenteral lipid emulsions on the metabolomic phenotype in preterm TPN-fed piglets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lipids in parenteral nutrition provide essential fatty acids and are a major source of energy for hospitalized neonates. Intralipid (IL) is the only approved lipid emulsion in the U.S, but new generation emulsions include Omegaven (OV) and SMOFlipid (SL). There are no studies describing the metaboli...

  4. 21 CFR 524.802 - Enrofloxacin and silver sulfadiazine otic emulsion.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Enrofloxacin and silver sulfadiazine otic emulsion... ANIMAL DRUGS § 524.802 Enrofloxacin and silver sulfadiazine otic emulsion. (a) Specifications. Each milliliter contains 5 milligrams (mg) enrofloxacin and 10 mg silver sulfadiazine. (b) Sponsor. See No....

  5. Reduction of lipid oxidation by formation of caseinate-oil-oat gum emulsions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The concentration of oat gum, though important for formation of stable emulsion, has no effect on oxidation of Omega 3 oil; this is most prominent in fish-oil based Omega 3 oil. The optimal concentration of oat gum is about 0.2% wt for emulsion stability and visual appearance. We found that concentr...

  6. Antagonistic effects between magnetite nanoparticles and a hydrophobic surfactant in highly concentrated Pickering emulsions.

    PubMed

    Vílchez, Alejandro; Rodríguez-Abreu, Carlos; Menner, Angelika; Bismarck, Alexander; Esquena, Jordi

    2014-05-13

    Herein we present a systematic study of the antagonistic interaction between magnetite nanoparticles (Fe3O4) and nonionic hydrophobic surfactant in Pickering highly concentrated emulsions. Interfacial tension measurements, phase behavior, and emulsion stability studies, combined with electron microscopy observations in polymerized systems and magnetometry, are used to support the discussion. First, stable W/O highly concentrated emulsions were obtained using partially hydrophobized magnetite nanoparticles. These emulsions experienced phase separation when surfactant is added at concentrations as low as 0.05 wt %. Such phase separation arises from the preferential affinity of the surfactant for the nanoparticle surfaces, which remarkably enhances their hydrophobicity, leading to a gradual desorption of nanoparticles from the interface. W/O emulsions were obtained at higher surfactant concentrations, but in this case, these emulsions were mainly stabilized by surfactant molecules. Therefore, stable emulsions could be prepared in two separate ranges of surfactant concentrations. After polymerization, low-density macroporous polymers were obtained, and the adsorption and aggregation of nanoparticles was analyzed by transmission electron microscopy. The progressive displacement of the nanoparticles was revealed: from the oil-water interface, in which aggregated nanoparticles were adsorbed, forming dense layers, to the continuous phase of the emulsions, where small nanoparticle aggregates were randomly dispersed. Interestingly, the results also show that the blocking temperature of the iron oxide superparamagnetic nanoparticles embedded in the macroporous polymers could be modulated by appropriate control of the concentrations of both surfactant and nanoparticles. PMID:24738961

  7. The Preparation and Testing of a Common Emulsion and Personal Care Product: Lotion

    ERIC Educational Resources Information Center

    Mabrouk, Suzanne T.

    2004-01-01

    A chemical analysis of lotions, which comprises of categorizations of moisturizers and emulsions, with the preparation and testing of three lotions, is done. The experiment piques students' interest in preparing lotions and emulsions, and proves the value of chemistry in satisfying the needs of everyday life.

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

    SciTech Connect

    Zhang Ying; Jin Chao

    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 trace 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

  9. Antagonistic effects between magnetite nanoparticles and a hydrophobic surfactant in highly concentrated Pickering emulsions.

    PubMed

    Vílchez, Alejandro; Rodríguez-Abreu, Carlos; Menner, Angelika; Bismarck, Alexander; Esquena, Jordi

    2014-05-13

    Herein we present a systematic study of the antagonistic interaction between magnetite nanoparticles (Fe3O4) and nonionic hydrophobic surfactant in Pickering highly concentrated emulsions. Interfacial tension measurements, phase behavior, and emulsion stability studies, combined with electron microscopy observations in polymerized systems and magnetometry, are used to support the discussion. First, stable W/O highly concentrated emulsions were obtained using partially hydrophobized magnetite nanoparticles. These emulsions experienced phase separation when surfactant is added at concentrations as low as 0.05 wt %. Such phase separation arises from the preferential affinity of the surfactant for the nanoparticle surfaces, which remarkably enhances their hydrophobicity, leading to a gradual desorption of nanoparticles from the interface. W/O emulsions were obtained at higher surfactant concentrations, but in this case, these emulsions were mainly stabilized by surfactant molecules. Therefore, stable emulsions could be prepared in two separate ranges of surfactant concentrations. After polymerization, low-density macroporous polymers were obtained, and the adsorption and aggregation of nanoparticles was analyzed by transmission electron microscopy. The progressive displacement of the nanoparticles was revealed: from the oil-water interface, in which aggregated nanoparticles were adsorbed, forming dense layers, to the continuous phase of the emulsions, where small nanoparticle aggregates were randomly dispersed. Interestingly, the results also show that the blocking temperature of the iron oxide superparamagnetic nanoparticles embedded in the macroporous polymers could be modulated by appropriate control of the concentrations of both surfactant and nanoparticles.

  10. Determination of emulsion explosives with Span-80 as emulsifier by gas chromatography-mass spectrometry.

    PubMed

    Tian, Fei-Fei; Yu, Jing; Hu, Jia-Hong; Zhang, Yong; Xie, Meng-Xia; Liu, Yuan; Wang, Xiang-Feng; Liu, Hai-Ling; Han, Jie

    2011-06-01

    A novel approach for identification and determination of emulsion explosives with Span-80 (sorbitol mono-oleate) as the emulsifier and their postblast residues by gas chromatography-mass spectrometry (GC-MS) has been developed. 24 kinds of emulsion explosives collected have been processed by transesterification reaction with metholic KOH solution and the emulsifier has turned into methyl esters of fatty acids. From the peak area ratios of their methyl esters, most of these emulsion explosives can be differentiated. In order to detect the postblast residues of emulsion explosives, the sorbitols in the emulsifier Span-80 obtained after transesterification reaction have been further derivatized by silylation reaction with N,O-bis-(trimethylsilyl)trifluoroacetamide (BSTFA) containing 1% trimethylchlorosilane (TMCS) as the derivatizing reagent. The derivatization conditions were optimized and the derivatives were determined by GC-MS. The results showed that the silylation derivatives of sorbitol and it isomers, combined with hydrocarbon compounds and methyl esters of fatty acids, were the characteristic components for identification of the emulsion explosives. The established approach was applied to analyze the postblast residues of emulsion explosives. It has been found that the method was sensitive and specific, especially when detecting the derivatives of sorbitol and its isomers by GC-MS in selecting ion mode. The information of the characteristic components can help probe the origin of the emulsion explosives and providing scientific evidences and clues for solving the crimes of the emulsion explosive explosion.

  11. Shewanella putrefaciens in a fuel-in-water emulsion from the Prestige oil spill.

    PubMed

    Martín-Gil, J; Ramos-Sánchez, M C; Martín-Gil, F J

    2004-10-01

    Microorganisms that colonize the fuel-in-water emulsion from the Prestige spill have been compared with those from Exxon-Valdez. Both emulsions contained non-fermentative gram-negative rods but unlike Exxon-Valdez's, the Prestige's spill contained anaerobic bacteria and no fungi. Our main finding has been the identification of Shewanella putrefaciens , a bacterium promising for bioremediation. PMID:15539931

  12. Emulsification by high frequency ultrasound using piezoelectric transducer: formation and stability of emulsifier free emulsion.

    PubMed

    Kaci, Messaouda; Meziani, Smail; Arab-Tehrany, Elmira; Gillet, Guillaume; Desjardins-Lavisse, Isabelle; Desobry, Stephane

    2014-05-01

    Emulsifier free emulsion was developed with a new patented technique for food and cosmetic applications. This emulsification process dispersed oil droplets in water without any emulsifier. Emulsions were prepared with different vegetable oil ratios 5%, 10% and 15% (v/v) using high frequency ultrasounds generated by piezoelectric ceramic transducer vibrating at 1.7 MHz. The emulsion was prepared with various emulsification times between 0 and 10h. Oil droplets size was measured by laser granulometry. The pH variation was monitored; electrophoretic mobility and conductivity variation were measured using Zêtasizer equipment during emulsification process. The results revealed that oil droplets average size decreased significantly (p<0.05) during the first 6h of emulsification process and that from 160 to 1 μm for emulsions with 5%, 10% and from 400 to 29 μm for emulsion with 15% of initial oil ratio. For all tested oil ratios, pH measurement showed significant decrease and negative electrophoretic mobility showed the accumulation of OH(-) at oil/water interface leading to droplets stability in the emulsion. The conductivity of emulsions showed a decrease of the ions quantity in solution, which indicated formation of positive charge layer around OH(-) structure. They constitute a double ionic layer around oil particles providing emulsion stability. This study showed a strong correlation between turbidity measurement and proportion of emulsified oil. PMID:24315670

  13. Cross-linking oppositely charged oil-in-water emulsions to enhance heteroaggregate stability.

    PubMed

    Maier, Christiane; Oechsle, Anja M; Weiss, Jochen

    2015-11-01

    The formation and subsequent enzymatic and chemical cross-linking of heteroaggregates from oppositely charged oil-in-water (O/W) emulsions was investigated. For this purpose, 10% (w/w) oil-in-water emulsions (d43<1 μm) were prepared at pH 4 using a positively charged emulsifier (Nα-lauroyl-L-arginine ethyl ester (LAE), cold water fish gelatin, or whey protein isolate) or a negatively charged one (sugar beet pectin or Quillaja saponins). The oppositely charged emulsions were then combined at a volume ratio of 1:1 and treated with laccase or glutaraldehyde in order to further stabilize the electrostatically attached aggregates by covalently cross-linking the oppositely charged membranes. Emulsions and heteroaggregates were characterized by their rheological properties, their surface charge, particle size distribution, and microstructure using dynamic and static light scattering as well as confocal laser scanning microscopy. Prior to cross-linking, the emulsifiers' stabilization mechanism were found to greatly influence the formation of heteroaggregates. Laccase treatment (1.34 mU/mL) increased aggregate expansion by ca. 30% for the combined emulsions stabilized by Quillaja saponins/whey protein isolate, while combined Quillaja saponins/fish gelatin stabilized emulsions remained unaffected. When combined emulsions were treated with 50mM glutaraldehyde, aggregate size significantly increased 2- and 3-fold, respectively. Thus, our study provides novel insights into the enzymatic and chemical cross-linking of heteroaggregates composed of oppositely charged O/W emulsions. PMID:26298085

  14. Preparation and impact of multiple (water-in-oil-in-water) emulsions in meat systems.

    PubMed

    Cofrades, S; Antoniou, I; Solas, M T; Herrero, A M; Jiménez-Colmenero, F

    2013-11-01

    The aim of this paper was to prepare and characterise multiple emulsions and assess their utility as pork backfat replacers in meat gel/emulsion model systems. In order to improve the fat content (in quantitative and qualitative terms) pork backfat was replaced by a water-in-oil-in-water emulsion (W1/O/W2) prepared with olive oil (as lipid phase), polyglycerol ester of polyricinoleic acid (PGPR) as a lipophilic emulsifier, and sodium caseinate (SC) and whey protein concentrate (WP) as hydrophilic emulsifiers. The emulsion properties (particle size and distribution, stability, microstructure) and meat model system characteristics (composition, texture, fat and water binding properties, and colour) of the W1/O/W2, as affected by reformulation, were evaluated. Multiple emulsions showed a well-defined monomodal distribution. Freshly prepared multiple emulsions showed good thermal stability (better using SC) with no creaming. The meat systems had good water and fat binding properties irrespective of formulation. The effect on texture by replacement of pork backfat by W1/O/W2 emulsions generally depends on the type of double emulsion (associated with the hydrophilic emulsifier used in its formulation) and the fat level in the meat system. PMID:23768366

  15. Mango butter emulsion gels as cocoa butter equivalents: physical, thermal, and mechanical analyses.

    PubMed

    Sagiri, Sai S; Sharma, Vijeta; Basak, Piyali; Pal, Kunal

    2014-11-26

    The search for cocoa butter equivalents in food and pharmaceutical industries has been gaining importance. In the present study, mango butter was explored as cocoa butter equivalent. Aqueous gelatin solution (20% w/w) containing cocoa butter and mango butter water-in-oil (fat) type emulsion gels were prepared by hot emulsification method. XRD and DSC melting profiles suggested the presence of unstable polymorphic forms (α and β') of fats in the emulsion gels. The crystal size and solid fat content analyses suggested that the presence of aqueous phase might have hindered the transformation of unstable polymorphic forms to stable polymorphic form (β) in the emulsion gels. Fat crystals in the emulsion gels were formed by instantaneous nucleation via either uni- or bidimensional growth (Avrami analysis). The viscoelastic nature of the emulsion gels was evaluated by modified Peleg's analysis (stress relaxation study). Results inferred that the physical, thermal, and mechanical properties of mango butter emulsion gels are comparable to those of cocoa butter emulsion gels. On the basis of preliminary studies, it was suggested that the mango butter emulsion gels may have potential to be used as cocoa butter equivalents.

  16. Shewanella putrefaciens in a fuel-in-water emulsion from the Prestige oil spill.

    PubMed

    Martín-Gil, J; Ramos-Sánchez, M C; Martín-Gil, F J

    2004-10-01

    Microorganisms that colonize the fuel-in-water emulsion from the Prestige spill have been compared with those from Exxon-Valdez. Both emulsions contained non-fermentative gram-negative rods but unlike Exxon-Valdez's, the Prestige's spill contained anaerobic bacteria and no fungi. Our main finding has been the identification of Shewanella putrefaciens , a bacterium promising for bioremediation.

  17. Optimization of folic acid nano-emulsification and encapsulation by maltodextrin-whey protein double emulsions.

    PubMed

    Assadpour, Elham; Maghsoudlou, Yahya; Jafari, Seid-Mahdi; Ghorbani, Mohammad; Aalami, Mehran

    2016-05-01

    Due to susceptibility of folic acid like many other vitamins to environmental and processing conditions, it is necessary to protect it by highly efficient methods such as micro/nano-encapsulation. Our aim was to prepare and optimize real water in oil nano-emulsions containing folic acid by a low energy (spontaneous) emulsification technique so that the final product could be encapsulated within maltodextrin-whey protein double emulsions. A non ionic surfactant (Span 80) was used for making nano-emulsions at three dispersed phase/surfactant ratios of 0.2, 0.6, and 1.0. Folic acid content was 1.0, 2.0, and 3.0mg/mL of dispersed phase by a volume fraction of 5.0, 8.5, and 12%. The final optimum nano-emulsion formulation with 12% dispersed phase, a water to surfactant ratio of 0.9 and folic acid content of 3mg/mL in dispersed phase was encapsulated within maltodextrin-whey protein double emulsions. It was found that the emulsification time for preparing nano-emulsions was between 4 to 16 h based on formulation variables. Droplet size decreased at higher surfactant contents and final nano-emulsions had a droplet size<100 nm. Shear viscosity was higher for those formulations containing more surfactant. Our results revealed that spontaneous method could be used successfully for preparing stable W/O nano-emulsions containing folic acid.

  18. Development of neutron measurement in high gamma field using new nuclear emulsion

    SciTech Connect

    Kawarabayashi, J.; Ishihara, K.; Takagi, K.; Tomita, H.; Iguchi, T.; Naka, T.; Morishima, K.; Maeda, S.

    2011-07-01

    To precisely measure the neutron emissions from a spent fuel assembly of a fast breeder reactor, we formed nuclear emulsions based on a non-sensitized Oscillation Project with Emulsion tracking Apparatus (OPERA) film with AgBr grain sizes of 60, 90, and 160 nm. The efficiency for {sup 252}Cf neutron detection of the new emulsion was calculated to be 0.7 x 10{sup -4}, which corresponded to an energy range from 0.3 to 2 MeV and was consistent with a preliminary estimate based on experimental results. The sensitivity of the new emulsion was also experimentally estimated by irradiating with 565 keV and 14 MeV neutrons. The emulsion with an AgBr grain size of 60 nm had the lowest sensitivity among the above three emulsions but was still sensitive enough to detect protons. Furthermore, the experimental data suggested that there was a threshold linear energy transfer of 15 keV/{mu}m for the new emulsion, below which no silver clusters developed. Further development of nuclear emulsion with an AgBr grain size of a few tens of nanometers will be the next stage of the present study. (authors)

  19. Conductivity reduction due to emulsification during surfactant enhanced-aquifer remediation. 1. Emulsion transport.

    PubMed

    Jain, Vivek; Demond, Avery H

    2002-12-15

    Surfactant-enhanced aquifer remediation (SEAR) is a promising technology for the remediation of subsurface zones contaminated with organic liquids. To ensure the success of SEAR, the potential reduction in hydraulic conductivity must be evaluated. The objective of this study was to examine the process of conductivity reduction due to the transport of an emulsion, generated by mixing tetrachloroethylene with 4% solutions of two nonionic surfactants, in packed beds of sand-sized silica particles. The injection of the emulsion resulted in a 75-85% reduction in conductivity, depending on the properties of the surfactant and the porous medium. The greater viscosity of the emulsion relative to that of water accounted for about 25% of the reduction. The remainder was attributed to the clogging of the porous medium by the emulsion. The relative sizes of the emulsion droplets and the packed bed's pores, coupled with measurements of zeta potential of the emulsion droplets and silica particles, suggested that multilayer deposition was the principal mechanism of clogging. This hypothesis was corroborated by direct observation of the emulsion transport process in a micromodel. To simulate the reduction in hydraulic conductivity in these systems accurately, it was necessary to modify the emulsion transport model by Soo and Radke to include the phenomena of viscosity variation and multilayering.

  20. Physical properties of emulsion-based hydroxypropyl methylcellulose films: effect of their microstructure.

    PubMed

    Zúñiga, R N; Skurtys, O; Osorio, F; Aguilera, J M; Pedreschi, F

    2012-10-01

    The initial characteristics of emulsions and the rearrangement of the oil droplets in the film matrix during film drying, which defines its microstructure, has an important role in the physical properties of the emulsion-based films. The objective of this work was to study the effect of the microstructure (two droplet size distributions) and stability (with or without surfactant) of HPMC oil-in-water emulsions over physical properties of HPMC emulsion-based edible films. HPMC was used to prepare sunflower oil-in-water emulsions containing 0.3 or 1.0% (w/w) of oil with or without SDS, as surfactant, using an ultrasonic homogenizer. Microstructure, rheological properties and stability of emulsions (creaming) were measured. In addition, microstructure, coalescence of oil droplets, surface free energy, optical and mechanical properties and water vapor transfer of HPMC films were evaluated. Image analysis did not show differences among droplet size distributions of emulsions prepared at different oil contents; however, by using SDS the droplet size distributions were shifted to lower values. Volume mean diameters were 3.79 and 3.77 μm for emulsions containing 0.3 and 1.0% without surfactant, respectively, and 2.72 and 2.71 μm for emulsions with SDS. Emulsions formulated with 1.0% of oil presented higher stability, with almost no change during 5 and 3 days of storage, for emulsions with and without SDS, respectively. Internal and surface microstructure of emulsion-based films was influenced by the degree of coalescence and creaming of the oil droplets. No effect of microstructure over the surface free energy of films was found. The incorporation of oil impaired the optical properties of films due to light scattering of light. Addition of oil and SDS decreased the stress at break of the emulsion-based films. The replace of HPMC by oil and SDS produce a lower "amount" of network structure in the films, leading to a weakening of their structure. The oil content and SDS