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Sample records for soap-free emulsion copolymerization

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

    PubMed

    Lee, Ki Chang; Choo, Hun Seung

    2015-10-01

    In order to study the surfactant-free emulsion copolymerization of benzyl methacrylate (BMA) with sodium 1-allyloxy-2-hydroxypropane sulfonate (COPS-I) and the resulting optical properties, a series of experiments was carried out at various reaction conditions such as the changes of BMA concentration, COPS-I concentration, BMA concentration under a fixed COPS-I amount, initiator and divinyl benzene (DVB) concentration. All the latices showed highly monodispersed spherical particles in the size range of 144~435 nm and the respective shiny structural colors from their colloidal photonic crystals. It is found that the changes in such polymerization factors greatly affect the number of particles and particle diameter, polymerization rate, molecular weight, zeta-potential, and refractive indices. The increase of number of particles led to the increased rate of polymerization and zeta-potential of the latices, on the other hand, to the decreased molecular weight. Refractive indices and the reflectivity increased with COPS-I concentration, on the other hand, and decreased with DVB concentration. Especially, refractive indices of the resulting poly[BMA-co-(COPS-I)] colloidal photonic crystals showed much higher values of 1.65~2.21 than that of polystyrene, due to the formation of core-shell shaped morphology. Monodisperse and high refractive index of poly[BMA-co-(COPS-I)] particles prepared in this work could be used for the study in photonic crystals and electrophoretic display. PMID:26726393

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

    PubMed

    Lee, Ki-Chang; Choo, Hun-Seung

    2014-11-01

    Narrowly dispersed poly(BMA-co-MMA) and PBMA latices with particle diameters ranging within 216-435 nm were synthesized successfully by surfactant-free emulsion polymerization with KPS and AIBA. The average particle diameter and particle size distribution, average molecular weight and its distribution, glass transition temperature, reflectance spectra in visible wavelength, and refractive indices for the respective poly(BMA-co-MMA) latices and their photonic crystals were systematically investigated in terms of BMA/MMA ratio, BMA content, polymerization temperature, and DVB effect. The rate of polymerization increased with increasing MMA concentration in BMA/MMA ratio. The particle diameter increased with BMA concentration in BMA/MMA ratio. The molecular weight increased with BMA concentration in BMA/MMA ratio and monomer concentration. The drying of the latices offered self-assembled shiny colloidal crystal films showing the characteristic structural colors in visible wavelength. All the poly(BMA-co-MMA) latices prepared in the study were fallen within the range of photonic grade microspheres. The reflectance measurement on the colloidal photonic crystals having different particle diameters clearly exhibited narrow stopbands. The reflection maxima (λ(max)) measured in this study were well close to the λ(max) calculated, derived from the Bragg's equation. The refractive indices of poly(BMA-co-MMA) photonic crystals were found to be almost same as the theoretical values and increased proportionally from 1.50 to 1.57 with BMA content in BMA/MMA ratios. It was, thus, found that the optical reflectance properties of the poly(BMA-co-MMA) colloidal photonic crystals can be controlled easily by adjusting the reaction conditions and BMA/MMA ratio in soap-free emulsion copolymerization of BMA and MMA. PMID:25958515

  4. 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

  5. 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

  6. Radiation-initiated emulsion copolymerization of styrene and carboxylic acid monomers. [Gamma radiation

    SciTech Connect

    Egusa, S.; Makuuchi, K.

    1982-03-01

    The emulsion copolymerization of styrene and carboxylic acid monomers such as acrylic, methacrylic, and itaconic acids (AAc, MAAc, IAc) was studied by using /sup 60/Co ..gamma..-rays as initiator and sodium dodecylsulfate as emulsifier. The polymerization behavior of these acid monomers was followed by simultaneous conductometric and potentiometric titrations for a latex sample taken in polymerization. The polymerization rate of these acid monomers increases in the following order of hydrophobicity: IAc < AAc < MAAc; this suggests that their polymerization sites are mainly the surface and/or subsurface regions of latex particles. The copolymerization rate of styrene and acid monomer increases with an increase in the acid monomer content for AAc and MAAc, whereas for IAc the rate decreases. The particle sizes determined by the stopped-flow method reveal that this variation of copolymerization rate cannot be explained by the number of growing particles and should be attributed to another factor; for instance, the transfer rate of styrene molecules from oil droplets to growing particles.

  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. Two-dimensional Raman correlation spectroscopy study of an emulsion copolymerization reaction process.

    PubMed

    Noda, Isao; Allen, William M; Lindberg, Seth E

    2009-02-01

    The emulsion copolymerization of styrene and 1,3-butadiene using an oligomeric nonionic surfactant as an emulsifier to make a styrene-butadiene rubber (SBR) copolymer latex was monitored by real-time in situ Raman spectroscopy. Time-resolved Raman spectra collected during the early stage of the polymerization reaction were subjected to a series of data analysis techniques, including two-dimensional (2D) correlation spectroscopy, multivariate self-modeling curve resolution (SMCR), and kernel analysis, to elucidate the fine details of the complex reaction process. Generalized 2D correlation analysis of time-resolved Raman spectra readily identified the characteristic Raman scattering bands for the monomers and copolymer. Cross-peaks appearing in 2D Raman correlation spectra showed that the decrease in the spectral intensity of Raman bands assignable to 1,3-butadiene occurs before the band intensity changes for styrene or SBR copolymer. The positions of asynchronous cross-peaks were used to identify a spectral region with the most distinct pattern of intensity variations, which in turn could be used as the starting point for the alternating least squares iteration of the SMCR analysis. SMCR analysis of the time-resolved Raman spectra generated a set of estimated pure component spectra and concentration profiles of styrene, 1,3-butadiene, and SBR copolymer without requiring independently measured calibration data. The estimated concentration profiles of monomers and copolymer indicated that the reaction of 1,3-butadiene started before the consumption of styrene and production of SBR copolymer. Kernel analysis of the estimated concentration profiles provided a succinct measure of the similarity and dissimilarity of the concentration changes of monomers and copolymer. PMID:19215653

  9. Monitoring of high solids content starved-semi-batch emulsion copolymerization reactions by Fourier transform Raman spectroscopy.

    PubMed

    Elizalde, Oihana; Asua, José M; Leiza, Jose R

    2005-10-01

    A high solids content n-butyl acrylate/methyl methacrylate emulsion copolymerization process carried out under starved semi-batch conditions was for the first time monitored on-line by means of Fourier transform (FT)-Raman spectroscopy. Partial least squares regression was employed to build calibration models that allowed relating the spectra with solids content (overall conversion), free amounts of both n-butyl acrylate (n-BA) and methyl methacrylate (MMA), and cumulative copolymer composition. In spite of the heterogeneous nature of the polymerization, the similarities of the spectra for MMA, n-BA, and for the copolymer, and the low monomer concentrations in the reactor, the FT-Raman spectroscopy has been shown to be a suitable noninvasive sensor to accurately monitor the process. Therefore, it is well suited for on-line control of all-acrylic polymerization systems. PMID:18028623

  10. Synthesis and characterization of self-crosslinking fluorinated polyacrylate soap-free latices with core-shell structure

    NASA Astrophysics Data System (ADS)

    Xu, Wei; An, Qiufeng; Hao, Lifen; Zhang, Dan; Zhang, Min

    2013-03-01

    Novel self-crosslinking fluorinated polyacrylate soap-free latices (FMBN) with core-shell structure were synthesized by semicontinuous seeded emulsion polymerization method from dodecafluoroheptyl methacrylate (DFMA), methyl methacrylate (MMA), butyl acrylate (BA), and N-methylolamide (NMA) in the presence of a polymerizable emulsifier-ammonium allyloxtmethylate nonylphenol ethoxylates sulfate (DNS-86). Effects of the DNS-86 and DFMA amounts on stability and properties of the FMBN emulsions were studied. Besides, the latices and their film were characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (1H NMR) spectrum, scanning electron microscopy (SEM), transmission electron microscopy (TEM), laser particle size analyzer, differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), contact angle goniometer, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), respectively. FT-IR spectra and 1H NMR spectrum showed that DFMA successfully participated in soap-free emulsion polymerization and monomers formed the fluorinated acrylate copolymer. The resulted latex particles had the core-shell structure. The films formed from the FMBN latices thus had two Tg. Their thermal stability and Tg of the shell phase increased gradually with augment of DFMA amount in polymer. XPS, AFM and hydrophobicity analyses indicated the fluoroalkyl groups had the tendency to enrich at the film-air interface. This enrichment of fluorine at the film-air interface was more evident after the annealing process. Water contact angles of the FMBN film before and after the annealing process could attain 115.5° and 117.5°, individually.

  11. 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

  12. Dynamic modeling of emulsion polymerization reactors

    SciTech Connect

    Penlidis, A.; Hamielec, A.E.; MacGregor, J.F.

    1985-06-01

    This paper is a survey of recent published works on the dynamic and steady state modeling of emulsion homo- and copolymerization in batch, semicontinuous , and continuous latex reactors. Contributions to our understanding of diffusion-controlled termination and propagation reactions, molecular weight, long chain branching and crosslinking development, polymer particle nucleation, and of the dynamics of continuous emulsion polymerization are critically reviewed.

  13. Radiopaque iodinated copolymeric nanoparticles for X-ray imaging applications.

    PubMed

    Aviv, Hagit; Bartling, Sonke; Kieslling, Fabian; Margel, Shlomo

    2009-10-01

    Recently we described iodinated homopolymeric radiopaque nanoparticles of 28.9+/-6.3 nm dry diameter synthesized by emulsion polymerization of 2-methacryloyloxyethyl(2,3,5-triiodobenzoate) (MAOETIB). The nanoparticle aqueous dispersion, however, was not stable and tended to agglomerate, particularly at weight concentration of dispersed nanoparticles above approximately 0.3%. The agglomeration rate increases as the concentration of nanoparticles in aqueous phase rises and prevents the potential in vivo use as contrast agent for medical X-ray imaging. Here we describe efforts to overcome this limitation by synthesis of iodinated copolymeric nanoparticles of 25.5+/-4.2 nm dry diameter, by emulsion copolymerization of the monomer, MAOETIB, with a low concentration of glycidyl methacrylate (GMA). The surface of resulting copolymeric nanoparticles is far more hydrophilic than that of polyMAOETIB (PMAOETIB) nanoparticles. Therefore, P(MAOETIB-GMA) nanoparticles are significantly more stable against agglomeration in aqueous continuous phase. After intravenous injection of P(MAOETIB-GMA) nanoparticles in rats and mice (including those with a liver cancer model) CT-imaging revealed a significant enhanced visibility of the blood pool for 30 min after injection. Later, lymph nodes, liver and spleen strongly enhanced due to nanoparticle uptake by the reticuloendothelial system. This favorably enabled the differentiation of cancerous from healthy liver tissue and suggests our particles for tumor imaging in liver and lymph nodes. PMID:19592085

  14. Reversible assembly of pH responsive branched copolymer-stabilised emulsion via electrostatic forces.

    PubMed

    Maçon, Anthony L B; Rehman, Saif Ur; Bell, Robert V; Weaver, Jonathan V M

    2016-01-01

    The judicious compositional and structural design of a branched co-polymeric surfactant allows for the production of highly stable oil in water emulsion droplets with reversible electrostatic aggregation behaviour. PMID:26503757

  15. 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.

  16. 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

  17. Preparation and characterization of film of poly vinyl acetate ethylene copolymer emulsion

    NASA Astrophysics Data System (ADS)

    Zhang, Yanhua; Gu, Jiyou; Tan, Haiyan; Shi, Junyou; Di, Mingwei; Zuo, Yingfeng; Qiu, Si

    2013-07-01

    In order to improve the storage modulus and water resistance of poly (vinyl acetate), the vinyl acetate and poly (vinyl alcohol) (PVA) were respectively used as monomers and protective colloid to prepare a new kind of polyvinyl acetate emulsion adhesive by continuous emulsion polymerization. The dynamic mechanics, particle distribution, glass transition temperature, polymer emulsion structure of both polymerized and copolymerized emulsion were analyzed by SEM, DMA and XPS, respectively. The results indicated that the copolymerized emulsion has the appropriate particle size and the uniform particle distribution, the glass transition temperature increased from 50 °C to 70 °C, compared with poly (vinyl acetate). It could be seen from XPS spectra of copolymerized emulsion that key characteristic peak of Cdbnd O was still existent. X-ray photoelectron spectra revealed that the addition of EVA did not generate the new bond, whereas the maximum percentage increases in ester was determined in the composite film with the introduction of EVA of 25%, which indicated that the composite film has copolymer structure. The storage modulus and water resistance of poly (vinyl acetate) were improved due to the introduction of the EVA.

  18. 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

  19. Study Of Laser-Induced Copolymerization

    NASA Technical Reports Server (NTRS)

    Miner, Gilda A.; Meador, Willard E.; Chang, C. Ken

    1993-01-01

    Report describes experiments on photopolymerization of styrene/maleic anhydride copolymer published as part of Laser Polymerization Program at NASA Langley Research Center. Presents basic study of copolymerization of styrene and maleic anhydride under laser-induced initiation and polymerization. Helps to clarify different theories on such initiation and represents significant advances in understanding of basic processes.

  20. Formation of fine particle emulsions by high-dose-rate polymerization

    SciTech Connect

    Hayashi, K.; Kijima, T.; Okamura, S.; Egusa, S.; Makuuchi, K.

    1982-12-01

    Emulsion of chloroprene, acrylic acid, styrene, n-butyl methacrylate, and 2-hydroxyethyl methacrylate monomers mixed with sodium lauryl sulfate as an emulsifier were polymerized or copolymerized in a flow system for control of temperature and for mixing of the emulsion under irradiation. Electron beams of a dose rate of 0.1 to 10 Mrad/s was used as a radiation source to produce very fine particle emulsions. Significant decreases in particle diameter were noted for polymers aged for as much as 5 weeks. (BLM)

  1. Monitoring the synthesis and properties of copolymeric polycations.

    PubMed

    González García, Gemma; Kreft, Tomasz; Alb, Alina M; de la Cal, José C; Asua, José M; Reed, Wayne F

    2008-11-20

    The kinetics; evolution of molar mass; solution conductivity, sigma; intrinsic viscosity; and average composition drift; and distribution were determined by monitoring the synthesis of copolymeric polycations of acrylamide (Am) and [2-(acryloyloxy)ethyl]-trimethylammonium chloride (Q9). The quantitative relationship between diminishing sigma and charged co-monomers incorporation was monitored for the first time and provided novel data on counterion condensation, which occurs gradually over a broad composition regime. This new capability allows predictions concerning the relationship between copolymer composition and linear charge density, xi, to be tested and models of trivariate mass, composition, and xi distributions to be built. This approach, hence, brings together the previously disparate fields of synthetic chemistry of copolymers and physical chemical properties of polyelectrolytes. Monitoring was achieved with a new implementation of the ACOMP (automatic continuous online monitoring of polymerization reactions) platform. Reactivity ratios determined by ACOMP were rQ9 = 0.47 and rAm = 1.10. Opposite trends in composition drift and final molar mass were found; low starting percentage of Q9 led to low composition drift and high molar mass, whereas the opposite was found at high starting percentage of Q9. Complementary end-product analysis by multidetector gel permeation chromatography supported the ACOMP results. End-product polyelectrolyte properties were characterized by automatic continuous mixing, revealing that combined electrostatic persistence length and excluded volume effects led to the expected large changes in polyelectrolyte conformation and interactions. These results set the groundwork for semibatch control of molar mass, composition, and xi, and eventually for monitoring and control for inverse emulsion-based reactions of this type. PMID:18783199

  2. 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

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. Recent Emulsion Technologies

    SciTech Connect

    Ariga, A.

    2011-10-06

    Emulsion technologies are very much developed in the last decade and still developing in both the emulsion gel and the data taking. Emulsion detectors are suitable for the neutrino experiments because they can distinguish all 3 flavors of neutrino. The OPERA experiment, a recent pillar in the emulsion experiments aiming at the first observation of the neutrino oscillation in CNGS beam in appearance mode, is running, showing the good capability to separate 3 flavor neutrino interactions. In this poster, the recent developments and prospects of the emulsions for the next generation experiments are reported.

  8. 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. PMID:25988487

  9. Method of breaking and emulsion and an emulsion-emulsion breaker composition

    SciTech Connect

    Salathiel, W. M.

    1985-05-14

    This invention relates to a composition of matter and to a method for producing a controllable, residue-free break of an emulsion or a dispersion of a water-in-oil emulsion. An emulsion breaker is incorporated into the emulsion. It is temporarily-protected (deactivated) so that breaking of the emulsion is initially avoided. By removing the protection, the breaker becomes active, and it acts to break the emulsion into its separate phases.

  10. Microfluidics with Gel Emulsions

    NASA Astrophysics Data System (ADS)

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

    2006-03-01

    Microfluidic processing is usually achieved using single phase liquids. Instead, we use monodisperse emulsions to compartment liquids within microchannel geometries. At low continuous phase volume fractions, droplets self-organize to form well-defined arrangements, analogous to foam. While it is well-known that confined geometries can induce rearrangement of foam compartments at the millimeter-scale, similar dynamics are also expected for gel emulsions. We have studied online generation, organization and manipulation of gel emulsions using a variety of microchannel geometries. ``Passive'' reorganization, based on fixed channel geometries, can be supplemented by ``active'' manipulation by incorporating a ferrofluid phase. A ferromagnetic phase facilitates reorganization of liquid compartments on demand using an electromagnetic trigger. Moreover, coalescence between adjacent compartments within a gel emulsion can be induced using electrical potential. Microfluidics using gel emulsions will be well-suited for combinatorial chemistry, DNA sequencing, drug screening and protein crystallizations.

  11. Rheology of emulsions.

    PubMed

    Derkach, Svetlana R

    2009-10-30

    The review is devoted to the historical and modern understanding of rheological properties of emulsions in a broad range of concentration. In the limiting case of dilute emulsions, the discussion is based on the analogy and differences in properties of suspensions and emulsions. For concentrated emulsions, the main peculiarities of their rheological behaviour are considered. Different approaches to understand the concentration dependencies of viscosity are presented and compared. The effects of non-Newtonian flow curves and the apparent transition to yielding with increasing concentration of the dispersed phase are discussed. The problem of droplet deformation in shear fields is touched. The highly concentrated emulsions (beyond the limit of closest packing of spherical particles) are treated as visco-plastic media, and the principle features of their rheology (elasticity, yielding, concentration and droplet size dependencies) are considered. A special attention is paid to the problem of shear stability of drops of an internal phase starting from the theory of the single drop behaviour, including approaches for the estimation of drops' stability in concentrated emulsions. Polymer blends are also treated as emulsions, though taking into account their peculiarities due to the coexistence of two interpenetrated phases. Different theoretical models of deformation of polymer drops were discussed bearing in mind the central goal of predictions of the visco-elastic properties of emulsions as functions of the properties of individual components and the interfacial layer. The role of surfactants is discussed from the point of view of stability of emulsions in time and their special influence on the rheology of emulsions. PMID:19683219

  12. 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.

  13. Tuning the critical solution temperature of polymers by copolymerization

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    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.

  14. 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.

  15. Catalysts for CO2/epoxide ring-opening copolymerization.

    PubMed

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

    2016-02-28

    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

  16. 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

  17. Stabilization of emulsions using polymeric surfactants based on inulin.

    PubMed

    Tadros, Th F; Vandamme, A; Levecke, B; Booten, K; Stevens, C V

    2004-05-20

    The use of polymeric surfactants for stabilization of emulsions is described. A brief account of general classification and description of polymeric surfactants is given. This is followed by a description of the adsorption and conformation of polymeric surfactants at interfaces. The theoretical approaches for studying polymer adsorption are briefly described. This is followed by a section on the experimental techniques that can be applied to study adsorption and conformation of polymers at the interface. Examples are given to illustrate the experimental techniques. A section is devoted to the interaction between droplets containing adsorbed polymer layers (steric stabilization). The last section gives results on oil-in-water (O/W) emulsions stabilised with a novel graft copolymeric surfactant based on inulin that has been modified by introducing alkyl groups. Two oils were used, namely Isopar M (isoparaffinic oil) and cyclomethicone. Emulsions prepared using the inulin-based surfactant have large droplets, but this could be significantly reduced by addition of a cosurfactant in the oil phase, namely Span 20. The stability of the emulsions was investigated in water, in 0.5, 1.0, 1.5 and 2 mol dm(-3) NaCl and in 0.5, 1.0, 1.5 and 2 mol dm(-3) MgSO(4). These emulsions were stable for more than 1 year up to 50 degrees C in NaCl concentrations up to 2 mol dm(-3) and 1 mol dm(-3) MgSO(4). This high stability in high electrolyte concentrations could be attributed to the nature of the hydrophilic (stabilizing) polyfructose chain. This was confirmed using cloud point measurements, which showed high hydration of the polyfructose chain in such high electrolyte concentrations. This ensured the long-term physical stability resulting from the strong steric repulsion between the polyfructose chains. PMID:15072943

  18. 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. PMID:24651200

  19. Radiation copolymerization of N-vinylpyrrolidone with crotonic acid

    SciTech Connect

    Solovskii, M.V.; Ushakova, V.N.; Panarin, E.F.; Boimirzaev, A.S.; Nesterov, V.V.; Persinen, A.A.; Mikhal'chenko, G.A.

    1987-09-01

    It was experimentally shown that the method of radiation initiation of copolymerization can be used to synthesize copolymers of N-vinylpyrrolidone with crotonic acid with controlled composition, molecular weights, and molecular weight distribution. These copolymers also include those with characteristics that satisfy the requirements for synthetic polymers serving as modifiers of biologically active compounds.

  20. 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

  1. 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

  2. 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.

  3. Low-temperature radiation copolymerization of tetrafluoroethylene with perfluorovinyl ethers

    SciTech Connect

    Kim, I.P.; Pirozhnaya, L.N.; Loginova, N.N.; Barkalov, I.M.

    1986-12-01

    The copolymerization of perfluorovinyl ethers with tetrafluoroethylene at low temperature was studied and compared with the process conducted with chemical initiation in bulk or aqueous medium. A calorimetric method was used for studying the kinetics of copolymerization, the phase state of the system, and the phase transition dynamics. Ampules containing the samples of monomers and mixtures were irradiated at 77/sup 0/K with /sup 60/Co ..gamma.. rays with a dose rate of 25 kGy/h. Radiolysis in the solid phase at 77/sup 0/K with a 130 kGy dose resulted in the formation of 0.5-1.0 wt.% of a polymer, and this polymer was soluble in the monomer.

  4. Magnetofluid emulsion: New magnetocontrolled media

    NASA Astrophysics Data System (ADS)

    Bashtovoi, Victor G.; Yarmolchik, Yuri P.

    1994-03-01

    This study has shown that flow dynamics of emulsion consisting of magnetic and nonmagnetic fluids depends on applied magnetic field. So these emulsions may be considered as a magnetic field controlled medium, and in particular as a magnetic field controlled heat carrier. The new dates on rheological properties of these emulsions in the presence of magnetic field are described.

  5. 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.

  6. 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.

  7. 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)

  8. 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

  9. 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…

  10. Produced fluid emulsions. Final report

    SciTech Connect

    Hurley, C.F.; Himmelblau, A.; Trom, L.

    1984-09-01

    Emulsion production and stabilization may be due to one or more of several phenomenon including water-oil ratio, oil and brine chemistry, and surfactant and polymer type and concentration. They may influence emulsification either independently or with dependence on one or more of the other factors. Task One has tried to define which factors are dominant and what effect variations in them will have on the emulsion characteristics for each of the fields investigated. Emulsions were produced using a hand homogenizer at a fixed setting for a specific length of time to ensure all samples were produced uniformly. A du Nouy apparatus was used to measure surface and interfacial tensions and a binocular microscope was used in the micro-visual studies. The emulsions were treated in a similar manner with a wide variety of materials to not only break them, but also to help define which mechanisms are responsible for the stabilization of a particular emulsion. Core floods in Task Two utilized a six-foot sand-pack for a mixing medium. A six-inch long Berea core which followed, provided shear similar to that of the reservoir. The choice of oil, brine, surfactant and polymer were chosen to correlate to the Task One studies. Similarities and differences in the results between the bench-top and core flood studies are noted. The conditions of emulsion production and characteristics and the effectiveness of emulsion breakers are compared to help determine the mechanism of emulsion stabilization. 8 figures, 85 tables.

  11. Wettability modification of rock cores by fluorinated copolymer emulsion for the enhancement of gas and oil recovery

    NASA Astrophysics Data System (ADS)

    Feng, Chunyan; Kong, Ying; Jiang, Guancheng; Yang, Jinrong; Pu, Chunsheng; Zhang, Yuzhong

    2012-07-01

    The fluorine-containing acrylate copolymer emulsion was prepared with butyl acrylate, methacrylic acid and 1H, 1H, 2H, 2H-perfluorooctyl acrylate as monomers. Moreover, the structure of the copolymer was verified by Fourier transform infrared (FTIR), nuclear magnetic resonance (1H NMR and 19F NMR) and X-ray photoelectron spectroscopy (XPS) analyses. The results showed that all the monomers had been copolymerized and the presence of fluorine moieties. The contact angle (CA) analyses, capillary rise and imbibition spontaneous tests were used to estimate the influence of the copolymer emulsion on the wettability of gas reservoirs. It was observed that the rock surface was of large contact angles of water, oilfield sewage, hexadecane and crude oil after treatment with the emulsion. The capillary rise results indicated that the contact angles of water/air and oil/air systems increased from 60° and 32° to 121° and 80°, respectively, due to the emulsion treatment. Similarly, because of wettability alteration by the fluoropolymer, the imbibition of water and oil in rock core decreased significantly. Experimental results demonstrated that the copolymer emulsion can alter the wettability of porous media from strong liquid-wetting to gas-wetting. This work provides a cost-effective method to prepare the fluoropolymer which can increase gas deliverability by altering the wettability of gas-condensate reservoirs and mitigating the water block effect.

  12. 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

  13. Direct Synthesis of Imidazolium-Functional Polyethylene by Insertion Copolymerization.

    PubMed

    Jian, Zhongbao; Leicht, Hannes; Mecking, Stefan

    2016-06-01

    Cationic imidazolium-functionalized polyethylene is accessible by insertion copolymerization of ethylene and allyl imidazolium tetrafluoroborate (AIm-BF4 ) with phosphinesulfonato palladium(II) catalyst precursors. Imidazolium-substituted repeat units are incorporated into the main chain and the initiating saturated chain end of the linear polymers, rather than the terminating unsaturated chain end. The counterion of the allyl imidazolium monomer is decisive, with the chloride analogue (AIm-Cl) no polymerization is observed. Stoichiometric studies reveal the formation of an inactive chloride complex from the catalyst precursor. An effect of moderate densities (0.5 mol%) of ionic groups on the copolymers' physical properties is exemplified by an enhanced wetting by water. PMID:27111477

  14. Dynamic optimization of a copolymerization reactor using tabu search.

    PubMed

    Anand, P; Rao, M Bhagvanth; Venkateswarlu, Ch

    2015-03-01

    A novel multistage dynamic optimization strategy based on meta-heuristic tabu search (TS) is proposed and evaluated through sequential and simultaneous implementation procedures by applying it to a semi-batch styrene-acrylonitrile (SAN) copolymerization reactor. The adaptive memory and responsive exploration features of TS are exploited to design the dynamic optimization strategy and compute the optimal control policies for temperature and monomer addition rate so as to achieve the desired product quality parameters expressed in terms of single and multiple objectives. The dynamic optimization results of TS sequential and TS simultaneous implementation strategies are analyzed and compared with those of a conventional optimization technique based on iterative dynamic programming (IDP). The simulation results demonstrate the usefulness of TS for optimal control of transient dynamic systems. PMID:25466914

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

    NASA Astrophysics Data System (ADS)

    Gaspard, P.; Andrieux, D.

    2014-07-01

    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.

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

    PubMed

    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. PMID:25084957

  17. 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.

  18. Protein Fibrils Induce Emulsion Stabilization.

    PubMed

    Peng, Jinfeng; Simon, Joana Ralfas; Venema, Paul; van der Linden, Erik

    2016-03-01

    The behavior of an oil-in-water emulsion was studied in the presence of protein fibrils for a wide range of fibril concentrations by using rheology, diffusing wave spectroscopy, and confocal laser scanning microscopy. Results showed that above a minimum fibril concentration depletion flocculation occurred, leading to oil droplet aggregation and enhanced creaming of the emulsion. Upon further increasing the concentration of the protein fibrils, the emulsions were stabilized. In this stable regime both aggregates of droplets and single droplets are present, and these aggregates are smaller than the aggregates in the flocculated emulsion samples at the lower fibril concentrations. The size of the droplet aggregates in the stabilized emulsions is independent of fibril concentration. In addition, the droplet aggregation was reversible upon dilution both by a pH 2 HCl solution and by a fibril solution at the same concentration. The viscosity of the emulsions containing fibrils was comparable to that of the pure fibril solution. Neither fibril networks nor droplet gel networks were observed in our study. The stabilization mechanism of emulsions containing long protein fibrils at high protein fibril concentrations points toward the mechanism of a kinetic stabilization. PMID:26882086

  19. Thermocapillary Motion in an Emulsion

    NASA Technical Reports Server (NTRS)

    Pukhnachov, Vladislav V.; Voinov, Oleg V.

    1996-01-01

    The phenomenological model for the motion of an emulsion or a gas-liquid mixture exposed to thermocapillary forces and micro-acceleration is formulated. The analytical and numerical investigation of one-dimensional flows for these media is fulfilled, the structure of discontinuous motion is studied. The stability conditions of a space-uniform state and of the interface between an emulsion and a pure liquid are obtained.

  20. Characterization of flaxseed oil emulsions.

    PubMed

    Lee, Pei-En; Choo, Wee-Sim

    2015-07-01

    The emulsifying capacity of surfactants (polysorbate 20, polysorbate 80 and soy lecithin) and proteins (soy protein isolate and whey protein isolate) in flaxseed oil was measured based on 1 % (w/w) of emulsifier. Surfactants showed significantly higher emulsifying capacity compared to the proteins (soy protein isolate and whey protein isolate) in flaxseed oil. The emulsion stability of the flaxseed oil emulsions with whey protein isolate (10 % w/w) prepared using a mixer was ranked in the following order: 1,000 rpm (58 min) ≈ 1,000 rpm (29 min) ≈ 2,000 rpm (35 min) >2,000 rpm (17.5 min). The emulsion stability of the flaxseed oil emulsions with whey protein isolate (10 % w/w) prepared using a homogenizer (Ultra Turrax) was independent of the speed and mixing time. The mean particle size of the flaxseed oil emulsions prepared using the two mixing devices ranged from 23.99 ± 1.34 μm to 47.22 ± 1.99 μm where else the particle size distribution and microstructure of the flaxseed oil emulsions demonstrated using microscopic imaging were quite similar. The flaxseed oil emulsions had a similar apparent viscosity and exhibited shear thinning (pseudoplastic) behavior. The flaxseed oil emulsions had L* value above 70 and was in the red-yellow color region (positive a* and b* values). PMID:26139903

  1. 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

  2. Copolymeric nanofilm platform for controlled and localized therapeutic delivery.

    PubMed

    Chow, Edward Kai-Hua; Pierstorff, Erik; Cheng, Genhong; Ho, Dean

    2008-01-01

    Nanomaterials such as block copolymeric membranes provide a platform for both cellular interrogation and biological mimicry. Their biomimetic properties are based upon the innate possession of hydrophilic and hydrophobic units that enable their integration with a broad range of therapeutic materials. As such, they can be engineered for specific applications in nanomedicine, including controlled/localized drug delivery. Here we describe a method for the functionalization of the polymethyloxazoline-polydimethylsiloxane-polymethyloxazoline (PMOXA-PDMS-PMOXA) block copolymer with anti-inflammatory molecules to develop copolymer-therapeutic hybrids, effectively conferring biological functionality to a versatile synthetic nanomembrane matrix and creating a platform for an anti-inflammatory drug delivery system. Utilizing self-assembly and Langmuir-Blodgett deposition methods, we mixed copolymers with dexamethasone (Dex), an anti-inflammatory glucocorticoid receptor agonist. The successful mixing of the copolymer with the drug was confirmed by surface pressure isotherms and fluorescence microscopy. Furthermore, at 4 nm thick per layer, orders of magnitude thinner than conventional drug delivery coatings, these dexamethasone-copolymer mixtures (PolyDex) suppressed in vitro expression of the inflammatory cytokines/signaling elements interleukin 6 (IL-6), interleukin 12 (IL-12), tumor necrosis factor alpha (TNFalpha), inducible nitric oxide synthase (iNOS), and interferon gamma inducible protein (IP-10). Finally, PolyDex maintained its anti-inflammatory properties in vivo confirmed through punch biopsies with tissue imagery via hematoxylin/eosin and macrophage specific staining using CD11b. Thus, we demonstrated that PolyDex may be utilized as a localized, highly efficient drug-copolymer composite for active therapeutic delivery to confer anti-inflammatory protection or as a platform material for broad drug elution capabilities. PMID:19206545

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

    PubMed Central

    2015-01-01

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

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

    PubMed

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

    2016-01-12

    Interconnected macroporous polymers were prepared by copolymerizing methyl acrylate (MA) via Pickering high internal phase emulsion (HIPE) templates with modified silica particles. The pore structure of the obtained polymer foams was observed by field-emission scanning electron microscopy (FE-SEM). Gas permeability was characterized to evaluate the interconnectivity of macroporous polymers. The polymerization shrinkage of continuous phase tends to form open pores while the solid particles surrounding the droplets act as barriers to produce closed pores. These two conflicting factors are crucial in determining the interconnectivity of macroporous polymers. Thus, poly-Pickering HIPEs with high permeability and well-defined pore structure can be achieved by tuning the MA content, the internal phase fraction, and the content of modified silica particles. PMID:26673546

  5. 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

  6. Emulsion Droplet Combustion in Microgravity: Water/Heptane Emulsions

    NASA Technical Reports Server (NTRS)

    Avedisian, C. Thomas

    1997-01-01

    This presentation reviews a series of experiments to further examine parametric effects on sooting processes of droplet flames in microgravity. The particular focus is on a fuel droplet emulsified with water, specifically emulsions of n-heptane as the fuel-phase and water as the dispersed phase. Water was selected as the additive because of its anticipated effect on soot formation, and the heptane fuel phase was chosen to theoretically reduce the likelihood of microexplosions because its boiling point is nearly the same as that of water: 100 C for water and 98 C for heptane. The water content was varied while the initial droplet diameter was kept within a small range. The experiments were carried out in microgravity to reduce the effects of buoyancy and to promote spherical symmetry in the burning process. Spherically symmetric droplet burning is a convenient starting point for analysis, but experimental data are difficult to obtain for this situation as evidenced by the fact that no quantitative data have been reported on unsupported emulsion droplet combustion in a convection-free environment. The present study improves upon past work carried out on emulsion droplet combustion in microgravity which employed emulsion droplets suspended from a fiber. The fiber can be instrusive to the emulsion droplet burning process as it can promote coalescence of the dispersed water phase and heterogeneous nucleation on the fiber. Prior work has shown that the presence of water in liquid hydrocarbons can have both beneficial and detrimental effects on the combustion process. Water is known to reduce soot formation and radiation heat transfer to combustor walls Gollahalli (1979) reduce flame temperatures and thereby NOx emissions, and encourage secondary droplet atomization or microexplosion. Water also tends to retard ignition and and promote early extinction. The former effect restricted the range of water volume fractions as discussed below.

  7. Statistical Ring Opening Metathesis Copolymerization of Norbornene and Cyclopentene by Grubbs' 1st-Generation Catalyst.

    PubMed

    Nikovia, Christiana; Maroudas, Andreas-Philippos; Goulis, Panagiotis; Tzimis, Dionysios; Paraskevopoulou, Patrina; Pitsikalis, Marinos

    2015-01-01

    Statistical copolymers of norbornene (NBE) with cyclopentene (CP) were prepared by ring-opening metathesis polymerization, employing the 1st-generation Grubbs' catalyst, in the presence or absence of triphenylphosphine, PPh₃. The reactivity ratios were estimated using the Finemann-Ross, inverted Finemann-Ross, and Kelen-Tüdos graphical methods, along with the computer program COPOINT, which evaluates the parameters of binary copolymerizations from comonomer/copolymer composition data by integrating a given copolymerization equation in its differential form. Structural parameters of the copolymers were obtained by calculating the dyad sequence fractions and the mean sequence length, which were derived using the monomer reactivity ratios. The kinetics of thermal decomposition of the copolymers along with the respective homopolymers was studied by thermogravimetric analysis within the framework of the Ozawa-Flynn-Wall and Kissinger methodologies. Finally, the effect of triphenylphosphine on the kinetics of copolymerization, the reactivity ratios, and the kinetics of thermal decomposition were examined. PMID:26343620

  8. 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.

  9. 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.

  10. 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

  11. Controlling molecular transport in minimal emulsions.

    PubMed

    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

  12. A novel crosslinker for UV copolymerization of N-vinyl pyrrolidone and methacrylates

    SciTech Connect

    Lai, Yu-Chin

    1993-12-31

    Methacryloxyethyl vinyl carbonate, a novel crosslinker containing a vinyl carbonate and a methacrylate group which is capable of copolymerizing N-vinyl pyrrolidone and methacrylates, was prepared. With this crosslinker, N-vinyl pyrrolidone and methacrylates can copolymerize efficiently under strictly UV condition. Previously, polymeric systems containing N-vinyl pyrrolidone and methacrylates were prepared using thermal initiators, or a combination of thermal and UV initiators in the presence of crosslinkers such as allyl methacrylate or ethylene glycol dimethacrylate, These processes often led to polymers with inferior properties and less controllable quality. The use of this novel crosslinker represents a sharp improvement in polymerization conditions (UV vs heat) as well as product quality.

  13. 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.

  14. 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

  15. 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.

  16. 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

  17. Changing Emulsion Dynamics with Heterogeneous Surface Wettability

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    We elucidate the effect of heterogeneous surface wettability on the morphology and dynamics of microfluidic emulsions, generated by a co-flowing device. We first design a useful methodology of modifying a micro-capillary with desired heterogeneous wettability, such as alternating hydrophilic and hydrophobic regions. Subsequently, the effects of flow rates and heterogeneous wettability on the emulsion morphology and motion in the micro-capillary are investigated. Our experimental data reveal a universal critical time scale of advective emulsions, above which the microfluidic emulsions remain intact, whereas below this time-scale emulsions become adhesive or inverse. A simple model based on a force balance can be used to explain this critical transition. These results show a control of emulsion dynamics by tuning the droplet size and the Capillary number, the ratio of viscous to surface effects, with heterogeneous surface wettability.

  18. 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

  19. Experiment S009: Nuclear Emulsion

    NASA Technical Reports Server (NTRS)

    Odell, F. W.; Shapiro, M. M.; Silberberg, R.; Stiller, B.; Tsao, C. H.; Durgaprasad, N.; Fichtel, C. E.; Guss, D. E.; Reames, D. V.

    1971-01-01

    The first exposure on a spacecraft of a nuclear emulsion apparatus designed to collect 1000 high quality tracks of heavy nuclei under a negligible thickness of matter (0.07 g/sq cm) is described. The cosmic ray detector consisted of a stack of nuclear emulsions that were designed to register at least 400 heavy nuclei tracks for each 10 hours of useful exposure. The spacecraft had to be oriented in a heads-up attitude during the 10-hour period to eliminate atmospheric albedo particles. The results are as follows: (1) a definite odd-even effect, with low abundances for elements of atomic number 7, 9, and 11; (2) a ratio O/C approximately 0.9; (3) Ne/C, Mg/C, and Si/C ratios between 0.2 and 0.3; (4) an abundance gap in the region 15 less than or equal to Z less than or equal to 19; and (5) a ratio (20 less than or equal to Z less than or equal to 28)/C 0.2, with a large concentration at Z = 26. These results are indicative that successful exposures of nuclear emulsions were obtained on the Gemini 11 mission.

  20. 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

  1. 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

  2. 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

  3. Spreading of Emulsions on Glass Substrates

    NASA Astrophysics Data System (ADS)

    Mohammad Karim, Alireza; Kavehpour, Pirouz

    2012-11-01

    The wettability of emulsions is an important factor with explicit influence in an extensive variety of industrial applications ranging from the petroleum to food industries. Surprisingly, there is no comprehensive study of emulsion spreading to date; this is due to the complexity of the structure of the emulsions and non-homogeneity of the dispersed phase bubbles in size as well as distribution through the emulsion. The spreading of water/silicone oil emulsions on glass substrates was investigated. The emulsions were prepared with varying volume fractions of water dispersed in silicone oil, with addition of small amounts of surfactant to stabilize the emulsion structure. The time dependent variation of dynamic contact angle, base diameter, and the spreading rate of the droplets of an emulsion are different from a pure substance. The effect of water/silicone oil weight percentage as well as the droplet size and dispersed phase bubble size were also investigated. The weight percentage of water/silicone oil emulsion and droplet size did not have significant influence on the spreading dynamics; however the dispersed phase drop size affected the spreading dynamics substantially.

  4. Deactivation efficiency of stabilized bactericidal emulsions.

    PubMed

    Vyhnalkova, Renata; Eisenberg, Adi; van de Ven, Theo G M

    2011-09-20

    Biocide emulsions stabilized with various stabilizing agents were prepared and characterized, and their efficiency in bacteria deactivation was evaluated. A number of stabilizing agents were tested for their stabilizing effect on emulsions of thiocyanomethylthiobenzothiazole (TCMTB) biocide. Two agents, the most successful in stabilizing the biocide, were chosen for further studies: high molecular weight polyethyleneimine (PEI) and an amphiphilic block copolymer of poly(caprolactone)-b-poly(acrylic acid) (PCL(33)-b-PAA(33)). The emulsion droplet sizes varied between 325 and 500 nm. Deactivation of bacteria was studied by exposing E. coli ATCC 11229 bacteria dispersions to emulsions stabilized by positively charged PEI or negatively charged PCL-b-PAA micelles and by measuring their absorbance; E. coli do not grow with time in the presence of biocide emulsions. PEI molecules alone act as biocide and deactivate the bacteria. PCL-b-PAA micelles as stabilizing agent do not affect the growth of the E. coli ; bacteria are deactivated by TCMTB released from the emulsion droplets. The kinetics of emulsion dissolution studies revealed for both stabilizing agents a decrease in droplet size with time while the emulsions were subjected to dialysis. The biocide was released from the emulsions within ∼250 min; the droplet shells consist mostly of PEI or PCL-b-PAA insoluble complexes with the biocide, which do not dissolve during dialysis. SEM images confirm the presence of residual crumbled shells with holes after 24 h of dialysis. PMID:21823610

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

    DOE PAGESBeta

    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

  6. 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.

  7. 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.

  8. 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.

  9. Suppression of Ostwald ripening in active emulsions.

    PubMed

    Zwicker, David; Hyman, Anthony A; Jülicher, Frank

    2015-07-01

    Emulsions consisting of droplets immersed in a fluid are typically unstable since they coarsen over time. One important coarsening process is Ostwald ripening, which is driven by the surface tension of the droplets. Stability of emulsions is relevant not only in complex fluids but also in biological cells, which contain liquidlike compartments, e.g., germ granules, Cajal bodies, and centrosomes. Such cellular systems are driven away from equilibrium, e.g., by chemical reactions, and thus can be called active emulsions. In this paper, we study such active emulsions by developing a coarse-grained description of the droplet dynamics, which we analyze for two different chemical reaction schemes. We first consider the simple case of first-order reactions, which leads to stable, monodisperse emulsions in which Ostwald ripening is suppressed within a range of chemical reaction rates. We then consider autocatalytic droplets, which catalyze the production of their own droplet material. Spontaneous nucleation of autocatalytic droplets is strongly suppressed and their emulsions are typically unstable. We show that autocatalytic droplets can be nucleated reliably and their emulsions stabilized by the help of chemically active cores, which catalyze the production of droplet material. In summary, different reaction schemes and catalytic cores can be used to stabilize emulsions and to control their properties. PMID:26274171

  10. Suppression of Ostwald ripening in active emulsions

    NASA Astrophysics Data System (ADS)

    Zwicker, David; Hyman, Anthony A.; Jülicher, Frank

    2015-07-01

    Emulsions consisting of droplets immersed in a fluid are typically unstable since they coarsen over time. One important coarsening process is Ostwald ripening, which is driven by the surface tension of the droplets. Stability of emulsions is relevant not only in complex fluids but also in biological cells, which contain liquidlike compartments, e.g., germ granules, Cajal bodies, and centrosomes. Such cellular systems are driven away from equilibrium, e.g., by chemical reactions, and thus can be called active emulsions. In this paper, we study such active emulsions by developing a coarse-grained description of the droplet dynamics, which we analyze for two different chemical reaction schemes. We first consider the simple case of first-order reactions, which leads to stable, monodisperse emulsions in which Ostwald ripening is suppressed within a range of chemical reaction rates. We then consider autocatalytic droplets, which catalyze the production of their own droplet material. Spontaneous nucleation of autocatalytic droplets is strongly suppressed and their emulsions are typically unstable. We show that autocatalytic droplets can be nucleated reliably and their emulsions stabilized by the help of chemically active cores, which catalyze the production of droplet material. In summary, different reaction schemes and catalytic cores can be used to stabilize emulsions and to control their properties.

  11. 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

  12. 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.

  13. Treatment of oil-in-water emulsions

    SciTech Connect

    Presley, C.T.; Harrison, R.J.

    1980-01-08

    Petroleum is separated from an oil-in-water emulsion containing water-soluble polymer such as polyacrylamide prior to refining by adding amphoteric metal cations (Zn, Al, Sn, and Co) to the emulsion to form a flocculate and then treating the resulting flocculate with a strong base to recover the oil and metal. 11 claims.

  14. Treatment of oil-in-water emulsions

    SciTech Connect

    Harrison, R.J.; Presley, C.T.

    1980-01-08

    Petroleum is separated from an ''oil-in-water'' emulsion containing water-soluble polymer prior to refining by adding amphoteric metal cations to the emulsion to form a flocculate and then treating the resulting flocculate with a strong base to recover the oil and metal.

  15. 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

  16. 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

  17. 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

  18. Cocoa particles for food emulsion stabilisation.

    PubMed

    Gould, Joanne; Vieira, Josélio; Wolf, Bettina

    2013-09-01

    Emulsifying properties of cocoa particles have been investigated in systems containing purified sunflower oil (PSO) and water at varying pH, concentration and source of cocoa particles including cocoa powders (CP), cocoa fibre (CF) and cocoa mass (CM). The effect of cocoa particle source, pH and cocoa particle concentration on emulsion stability was evaluated by following changes in characteristic droplet diameter. Size distributions acquired on the emulsions and aqueous cocoa particle suspensions overlapped. Based on cryo-SEM imaging of the emulsions, isolation of cocoa particle fines and a process of washing the cocoa particles to remove any water soluble molecules, it was concluded that the cocoa particle fines not captured by the small angle laser diffraction method employed for sizing, act as Pickering particles. This research has demonstrated a universal nature of a natural food particle to stabilise oil-in-water emulsions not requiring particle modification or adjusting of the solution properties of the emulsion phases. PMID:23851644

  19. Emulsion based cast booster - a priming system

    SciTech Connect

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

    2005-07-01

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

  20. Anticancer drug release from poly(N-isopropylacrylamide/itaconic acid) copolymeric hydrogels

    NASA Astrophysics Data System (ADS)

    Taşdelen, B.; Kayaman-Apohan, N.; Güven, O.; Baysal, B. M.

    2005-08-01

    The drug uptake and release of anticancer drug from N-isopropylacrylamide/itaconic acid copolymeric hydrogels containing 0-3 mol% of itaconic acid irradiated at 48 kGy have been investigated. 5-Fluorouracil (5-FU) is used as a model anticancer drug. The effect of 5-FU solution on swelling characteristics of PNIPAAm and P(NIPAAm/IA) copolymeric hydrogels have also been studied. The percent swelling, equilibrium swelling, equilibrium water/5-FU content and diffusion constant values are evaluated for poly(N-isopropylacrylamide) (PNIPAAm) and poly(N-isopropylacrylamide/itaconic) (P(NIPAAm/IA)) hydrogels at 130 ppm of 5-FU solution at room temperature. Diffusion of 5-FU solution into the hydrogels has been found to be the non-Fickian type. Finally, the kinetics of drug release from the hydrogels are examined.

  1. 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.

  2. 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.

  3. 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.

  4. Tailored Living Block Copolymerization: Multiblock Poly(cyclohexene carbonate)s with Sequence Control

    SciTech Connect

    Kim, Jeung Gon; Cowman, Christina D.; LaPointe, Anne M.; Wiesner, Ulrich; Coates, Geoffrey W.

    2011-03-08

    In this Communication, the living block copolymerization of functionalized cyclohexene oxides and CO{sub 2} is described, yielding multiblock poly(cyclohexene carbonate)s [p(CHC)s] with a diverse range of functionality on the side chains and good control of block sequence and length. Unlike prior systems that contain stable vinyl backbones, the carbonate backbones of polymers reported herein are degradable, allowing possible applications where removable templates are required.

  5. NEWS: Nuclear emulsion WIMP search

    NASA Astrophysics Data System (ADS)

    Alexandrov, A.; Asada, T.; D'Ambrosio, N.; De Lellis, G.; Di Crescenzo, A.; Di Marco, N.; Furuya, S.; Gentile, V.; Hakamata, K.; Ishikawa, M.; Katsuragawa, T.; Kuwabara, K.; Machii, S.; Naka, T.; Pupilli, F.; Sirignano, C.; Tawara, Y.; Tioukov, V.; Umemoto, A.; Yoshimoto, M.

    2015-01-01

    The most convincing candidate as main constituent of the dark matter in the Universe consists of Weakly Interacting Massive Particles (WIMPs). WIMPs must be electrically neutral and interact with a very low cross-section ( σ<10^{-40} cm2) which makes them detectable in direct searches only through the observation of nuclear recoils induced by the WIMP rare scatterings. In the experiments carried out so far, recoiled nuclei are searched for as a signal over a background produced by Compton electrons and neutron scatterings. Signal found by some experiments have not been confirmed by other techniques. We propose an R&D program for a new experimental method able to observe the track of the scattered nucleus based on new developments in the nuclear emulsion technique. Nuclear emulsions would act both as the WIMP target and as the tracking detector able to reconstruct the direction of the recoiled nucleus. This unique characteristic would provide a new and unambiguous signature of the presence of the dark matter in our galaxy.

  6. 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.

  7. 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.

  8. Emulsions on demand using microsturctured devices

    NASA Astrophysics Data System (ADS)

    Mahe, Christian; Tranchant, Jean Francois; Tromeur, Melanie; Schwesinger, Norbert

    2003-01-01

    Emulsions are very common in the field of cosmetics. Unfortunately, most emulsions contain ineffective substances to increase the stability of the products for a long time. These stabilizers can cause some severe healthy problems in several cases. One possible solution is the production of emulsions on demand to prevent the use of stabilizers. Stable emulsion can be achieved if the diameters of the droplets of one solution surrounded by a second solution are smaller than 1μm. Microstructured devices are suited in principle to generate such droplet distributions. Basic task of the development was a micro emulsifier that can be integrated into cosmetic flacons and that can deliver emulsions on demand by pressing a human fingertip onto a part of the flacon. Standardized cosmetic flacons have been used as basic devices. They consist of two separate glass bottles for two different liquid phases and two mechanical pumps integrated in a multifunctional cap. Regarding the viscosity ranges of the two liquids different microemulsifier structures have been developed. External dimensions and connections of the device have been chosen in a way that allows an integration of the devices into the cap. The second design conists of several streaming paths in parallel that allow a reduction of the pressure drop. Furthermore, it consists of three structured silicon chips bonded together. Emulsions with a stability of about 15-30 min have been achieved without any stabilizers. External forces of less than 10N were sufficient to generate emulsions on demand.

  9. High acyl gellan as an emulsion stabilizer.

    PubMed

    Vilela, Joice Aline Pires; da Cunha, Rosiane Lopes

    2016-03-30

    High acyl gellan (0.01-0.2% w/w) was used as stabilizer in oil in water emulsions containing 30% (w/w) of sunflower oil and prepared under different process conditions. Stable emulsions to phase separation could be obtained using high acyl gellan (HA) content above 0.05% (w/w), while low acyl gellan (LA) prepared at the same conditions could not stabilize emulsions. Emulsions properties depended on the process used to mix the oil and gellan dispersion since high pressure homogenization favored stabilization while very high energy density applied by ultrasound led to systems destabilization. Emulsions prepared using high pressure homogenization showed zeta potential values ranging from -50 up to -59 mV, suggesting that electrostatic repulsion could be contributing to the systems stability. Rheological properties of continuous phase were also responsible for emulsions stabilization, since HA gellan dispersions showed high viscosity and gel-like behavior. The high viscosity of the continuous phase could be associated to the presence of high acyl gellan microgels/aggregates. Disentanglement of these aggregates performed by ultrasound strongly decreased the viscosity and consequently affected the emulsions behavior, reducing the stability to phase separation. PMID:26794954

  10. Double emulsions in a microfluidic device

    NASA Astrophysics Data System (ADS)

    Pannacci, Nicolas; Lockhart, Thibaut; Willaime, Hervé; Tabeling, Patrick

    2007-11-01

    Double emulsions (emulsion of two liquids dispersed in a third liquid phase) are widely used in cosmetics, medicine or food industry. We are interested in producing very well controlled double emulsions in a microfluidic device and predicting the morphology (complete engulfing, non-engulfing or partial engulfing called ``janus'') from classical energetic considerations. We use a double flow focusing geometry with a 100 micrometers cross section for the PDMS microsystem. We compare theoretical and experimental morphologies flowing thirty triplets of immiscible fluids. We observe quite a good agreement and show that microfluidic technology may permit to get non standard objects.

  11. Hydrodynamic model for drying emulsions

    NASA Astrophysics Data System (ADS)

    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.

  12. Development of Highly Active and Regioselective Catalysts for the Copolymerization of Epoxides with Cyclic Anhydrides: An Unanticipated Effect of Electronic Variation.

    PubMed

    DiCiccio, Angela M; Longo, Julie M; Rodríguez-Calero, Gabriel G; Coates, Geoffrey W

    2016-06-01

    Recent developments in polyester synthesis have established several systems based on zinc, chromium, cobalt, and aluminum catalysts for the ring-opening alternating copolymerization of epoxides with cyclic anhydrides. However, to date, regioselective processes for this copolymerization have remained relatively unexplored. Herein we report the development of a highly active, regioselective system for the copolymerization of a variety of terminal epoxides and cyclic anhydrides. Unexpectedly, electron withdrawing substituents on the salen framework resulted in a more redox stable Co(III) species and longer catalyst lifetime. Using enantiopure propylene oxide, we synthesized semicrystalline polyesters via the copolymerization of a range of epoxide/anhydride monomer pairs. PMID:27171536

  13. Aging properties of Kodak type 101 emulsions

    NASA Technical Reports Server (NTRS)

    Dohne, B.; Feldman, U.; Neupert, W.

    1984-01-01

    Aging tests for several batches of Kodak type 101 emulsion show that storage conditions significantly influence how well the film will maintain its sensitometric properties, with sensitivity and density increasing to a maximum during this period. Any further aging may result in higher fog levels and sensitivity loss. It is noted that storage in an environment free of photographically active compounds allows film property optimization, and that film batches with different sensitivities age differently. Emulsions with maximum 1700-A sensitivity are 2.5 times faster than those at the low end of the sensitivity scale. These sensitive emulsions exhibit significantly accelerated changes in aging properties. Their use in space applications requires careful consideration of time and temperature profiles, encouraging the use of less sensitive emulsions when the controllability of these factors is limited.

  14. 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.

  15. Preparation of amphiphilic glycopolymers with flexible long side chain and their use as stabilizer for emulsion polymerization.

    PubMed

    Alvárez-Paino, Marta; Juan-Rodríguez, Rafael; Cuervo-Rodríguez, Rocío; Muñoz-Bonilla, Alexandra; Fernández-García, Marta

    2014-03-01

    A glycomonomer was synthesized from poly(ethylene glycol) methacrylate (PEGMA). The terminal hydroxyl moieties were activated with ester groups and subsequently the glucosamine was incorporated forming urethane linkages. The obtained glycomonomer was copolymerized with methyl acrylate by free radical polymerization varying the initial feed composition to produce different amphiphilic glycopolymers. The glycopolymers were then characterized and compared with the homologous glycopolymers based on 2-{[(D-glucosamin-2-N-yl)carbonyl]oxy}ethyl methacrylate. Both series of glycopolymers were used in emulsion polymerization of methyl acrylate as stabilizers without the addition of any cosurfactant. Although high conversions were not achieved with any of the employed surfactant, the glycopolymers provide good colloidal stability, spherical, monodisperse and small latex particles in comparison with the surfactant-free emulsion polymerization. The latex particles stabilized with the glycosurfactant based on PEGMA, containing a flexible spacer between the backbone and the glucosamine, lead to smooth films whereas the short side chain surfactant from 2-hydroxyethyl methacrylate (HEMA), with higher glass transition temperature, restricts the coalescence of particles and, therefore, the film formation. Moreover, the surface bioactivity of these polymer coatings was examined by analyzing their specific interaction with the lectin, Concanavalin A, Canavalia ensiformis. The specific and successful binding to the Concanavalin A was demonstrated by fluorescence microscopy for both series being more intense with increasing amount of glycounits in the glycopolymer stabilizers. Interestingly, the incorporation of a flexible spacer in the glycopolymer structures enhances the binding activity. PMID:24407696

  16. All-acrylic film-forming colloidal polymer/silica nanocomposite particles prepared by aqueous emulsion polymerization.

    PubMed

    Fielding, Lee A; Tonnar, Jeff; Armes, Steven P

    2011-09-01

    The efficient synthesis of all-acrylic, film-forming, core-shell colloidal nanocomposite particles via in situ aqueous emulsion copolymerization of methyl methacrylate with n-butyl acrylate in the presence of a glycerol-functionalized ultrafine silica sol using a cationic azo initiator at 60 °C is reported. It is shown that relatively monodisperse nanocomposite particles can be produced with typical mean weight-average diameters of 140-330 nm and silica contents of up to 39 wt %. The importance of surface functionalization of the silica sol is highlighted, and it is demonstrated that systematic variation of parameters such as the initial silica sol concentration and initiator concentration affect both the mean particle diameter and the silica aggregation efficiency. The nanocomposite morphology comprises a copolymer core and a particulate silica shell, as determined by aqueous electrophoresis, X-ray photoelectron spectroscopy, and electron microscopy. Moreover, it is shown that films cast from n-butyl acrylate-rich copolymer/silica nanocomposite dispersions are significantly more transparent than those prepared from the poly(styrene-co-n-butyl acrylate)/silica nanocomposite particles reported previously. In the case of the aqueous emulsion homopolymerization of methyl methacrylate in the presence of ultrafine silica, a particle formation mechanism is proposed to account for the various experimental observations made when periodically sampling such nanocomposite syntheses at intermediate comonomer conversions. PMID:21776995

  17. Method for treating tar sands emulsion and apparatus therefor

    SciTech Connect

    Bialek, R.F.

    1986-04-15

    A method is described for resolving a hot bitumen emulsion comprised primarily of bitumen, water and chemical diluents. The method consists of: providing separate but communicated emulsion mixing, and emulsion settling chamber, passing the hot bitumen emulsion through a first elongated mixing passage in the mixing chamber wherein a rapidly flowing stream of recycled emulsion is combined with a minor portion of unrecycled bitumen emulsion, to form a combined bitumen emulsion stream, thereafter passing the combined bitumen emulsion stream into an elongated discontinuous mixing passage comprised of vertically arranged and interconnected mixing passages within the emulsion mixer, where in the combined bitumen emulsion stream passes at a slower rate than in the first elongated mixing passage, passing the combined bitumen emulsion stream into an overflow passage communicated with the second elongated mixing passage, introducing a part of the combined emulsion stream from the overflow passage into the emulsion settling chamber, recycling the remainder of the combined emulsion stream from the overflow passage into the first elongated mixing passage, and removing separated flows of bitumen and water from the settling chamber.

  18. 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

  19. 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

  20. 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....

  1. 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

  2. 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.

  3. 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

  4. 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)

  5. 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

  6. 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

  7. Role of the cocatalyst in the copolymerization of CO2 and cyclohexene oxide utilizing chromium salen complexes.

    PubMed

    Darensbourg, Donald J; Mackiewicz, Ryan M; Rodgers, Jody L

    2005-10-12

    The mechanism of the copolymerization of cyclohexene oxide and carbon dioxide to afford poly(cyclohexylene)carbonate catalyzed by (salen)CrN3 (H2salen = N,N,'-bis(3,5-di-tert-butylsalicylidene)-1,2-ethylene-diimine) in the presence of a broad range of cocatalysts has been studied. We have previously established the rate of copolymer formation to be very sensitive to both the electron-donating ability of the salen ligand and the [cocatalyst], where N-heterocyclic amines, phosphines, and ionic salts were effective cocatalysts. Significant increases in the rate of copolymerization have been achieved with turnover frequencies of approximately 1200 h(-1), thereby making these catalyst systems some of the most active and robust thus far uncovered. Herein we offer a detailed explanation of the role of the cocatalyst in the copolymerization of CO2 and cyclohexene oxide catalyzed by chromium salen derivatives. A salient feature of the N-heterocyclic amine- or phosphine-cocatalyzed processes is the presence of an initiation period prior to reaching the maximum rate of copolymerization. Importantly, this is not observed for comparable processes involving ionic salts as cocatalysts, e.g., PPN+ X-. In these latter cases the copolymerization reaction exhibits ideal kinetic behavior and is proposed to proceed via a reaction pathway involving anionic six-coordinate (salen)Cr(N3)X- derivatives. By way of infrared and 31P NMR spectroscopic studies, coupled with in situ kinetic monitoring of the reactions, a mechanism of copolymerization is proposed where the neutral cocatalysts react with CO2 and/or epoxide to produce inner salts or zwitterions which behave in a manner similar to that of ionic salts. PMID:16201825

  8. 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.

  9. 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. PMID:16573041

  10. 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. PMID:26991465

  11. Relative Rates for Plasma Homo- and Copolymerizations of Olefins in a Homologous Series of Fluorinated Ethylenes

    NASA Technical Reports Server (NTRS)

    Golub, Morton A.; Wydeven, Theodore; Kliss, Mark (Technical Monitor)

    1996-01-01

    The relative rates of plasma (co)polymerizations of ethylene, vinyl fluoride, vinylidene fluoride, trifluoroethylene and tetrafluoroethylene (VF(sub x); x = 0-4, respectively) were determined in an rf, capacitively coupled, tubular reactor with external electrodes using identical plasma parameters. The averages of deposition rates obtained by both microgravimetry and ellipsometry were plotted versus the F/C ratios of the monomers or monomer blends. The deposition rates for VF(sub x)(x = 1-3) and 20 monomer blends were all located above a straight line joining the rates for VF(sub 0) and VF(sub 4), following a concave-downward plot of deposition rate versus F/C ratio similar to that reported previously for VF(sub 0)/VF(sub 4) blends. The deposition rates for VF(sub m)/VF(sub n) blends (m = 3 or 4; n = 0-2) were all greater than expected for non-interacting monomers; those for VF(sub 0)/VF(sub 2) and VF(sub 1)/VF(sub 2) blends were all lower than expected; while those for VF(sub 0)/VF(sub 1) and VF(sub 3)/VF(sub 4) blends fen on a straightline plot versus F/C ratio, indicative of apparent non-interaction between monomers. The mechanisms for plasma (co)polymerizations of VF(sub x) monomers responsible for the wide range of relative deposition rates remain to be elucidated.

  12. 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. PMID:17441756

  13. Reversion of pH-Induced Physiological Drug Resistance: A Novel Function of Copolymeric Nanoparticles

    PubMed Central

    Li, Rutian; Xie, Li; Zhu, Zhenshu; Liu, Qin; Hu, Yong; Jiang, Xiqun; Yu, Lixia; Qian, Xiaoping; Guo, Wanhua; Ding, Yitao; Liu, Baorui

    2011-01-01

    Aims The extracellular pH of cancer cells is lower than the intracellular pH. Weakly basic anticancer drugs will be protonated extracellularly and display a decreased intracellular concentration. In this study, we show that copolymeric nanoparticles (NPs) are able to overcome this “pH-induced physiological drug resistance” (PIPDR) by delivering drugs to the cancer cells via endocytosis rather than passive diffussion. Materials and Methods As a model nanoparticle, Tetradrine (Tet, Pka 7.80) was incorporated into mPEG-PCL. The effectiveness of free Tet and Tet-NPs were compared at different extracellular pHs (pH values 6.8 and 7.4, respectively) by MTT assay, morphological observation and apoptotic analysis in vitro and on a murine model by tumor volume measurement, PET-CT scanning and side effect evaluation in vivo. Results The cytotoxicity of free Tet decreased prominently (P<0.05) when the extracellular pH decreased from 7.4 to 6.8. Meanwhile, the cytotoxicity of Tet-NPs was not significantly influenced by reduced pH. In vivo experiment also revealed that Tet-NPs reversed PIPDR more effectively than other existing methods and with much less side effects. Conclusion The reversion of PIPDR is a new discovered mechanism of copolymeric NPs. This study emphasized the importance of cancer microenvironmental factors in anticancer drug resistance and revealed the superiority of nanoscale drug carrier from a different aspect. PMID:21966359

  14. 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. PMID:25992648

  15. Photo-induced alternating copolymerization of N-substituted maleimides and electron donor olefins

    NASA Astrophysics Data System (ADS)

    Jönsson, S.; Sundell, P. E.; Shimose, M.; Clark, S.; Miller, C.; Morel, F.; Decker, C.; Hoyle, C. E.

    1997-08-01

    Photo-initiated free radical polymerization of donor/acceptor type monomers have gained considerable interest due to the possibility of formulating UV curable non-acrylate systems. Recently, we described a photoinitiator free system based on donor/acceptor combinations [1-7]. Photoinitiator free nonacrylate based compositions will of course attain an enhanced interest and importance because of a broader selection of raw materials and combinations thereof, potential outdoor use, lower costs of formulations, improved odour, no formation of benzaldehyde, less extractables and so on. Recent developments of the direct photolysis of these acceptors and complexes, and their potential use in practical "UV curing" will be outlined. By a selective combination of A and D type monomers, a direct photolysis of the ground state complex (CTC) or the excitation of the acceptor, followed by the formation of an exciplex, will initiate a free radical copolymerization. A second route of direct initiation is based on inter- or intra-molecular H-abstraction from an excited state acceptor or exciplex. This paper will focus on the photochemistry as it relates to initiation of polymerization depending on acceptor and donor strength of the monomer system. Inherently different reactivities in air and nitrogen of donors and acceptors are compared to photoinitiator containing acrylates. Furthermore, the ratio of homo and alternating copolymerization as well as the 2 + 2 cycloaddition will be discussed.

  16. 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

  17. 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.

  18. A DFT Study on the Co-polymerization of CO2 and Ethylene: Feasibility Analysis for the Direct Synthesis of Polyethylene Esters.

    PubMed

    Moha, Verena; Cozzula, Daniela; Hölscher, Markus; Leitner, Walter; Müller, Thomas E

    2016-07-01

    The co-polymerization of CO2 with the non-polar monomer ethylene, though highly desirable, still presents a challenge whereas the palladium-catalyzed CO/C2 H4 co-polymerization is well understood. Building on this analogy, the goal of this study was to elucidate the feasibility of developing suitable catalysts for co-polymerizing CO2 with ethylene to polyethylene esters. Computational methods based on density functional theory were hereby employed. In the search for new catalyst lead structures, a closed catalytic cycle was identified for the palladium-catalyzed CO2 /C2 H4 co-polymerization reaction. The computational study on palladium complexes with a substituted anionic 2-[bis(2,4-dimethoxyphenyl)-phosphine]-benzene-2-hydroxo ligand revealed key aspects that need to be considered when designing ligand sets for potential catalysts for the non-alternating co-polymerization of CO2 and ethylene. PMID:27322770

  19. Aging mechanism in model Pickering emulsion.

    PubMed

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

    2016-01-21

    We study the stability of a model Pickering emulsion system using fluorinated oil and functionalized silica nanoparticles. A special counter-flow microfluidic set-up was used to prepare monodisperse 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 microfluidic setup. For surface coverage as low as 23%, we observed a regime of Pickering emulsion stability where the surface coverage of emulsion droplets of constant size increases with time, coexisting with an excess of oil 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. PMID:26549639

  20. Electrodynamic treatment of reversed-type emulsions

    SciTech Connect

    Skachkov, A.E.; Lavrov, I.S.; Timonov, S.M.

    1985-11-01

    The authors have produced an inhomogeneous electric field in processing reversed emulsions by using the oscillations of conducting spheres in an electric field; this is known as the electrical pendulum effect. The apparatus for the electrodynamic treatment of reversed-type emulsion is shown and the physical characteristics (density, kinematic viscosity, dielectric constant) are shown for the hydrocarbons used: hexane, octane, hexadecane and diesel fuel. It is shown that there is a minimum in the dependence of the residual water content after electrodynamic treatment on the external field strength; the minimum shifts to larger external field strength as the viscosity increases.

  1. RAFT copolymerization of itaconic anhydride and 2-methoxyethyl acrylate: a multifunctional scaffold for preparation of "clickable" gold nanoparticles.

    PubMed

    Javakhishvili, Irakli; Kasama, Takeshi; Jankova, Katja; Hvilsted, Søren

    2013-05-25

    RAFT copolymerization of 2-methoxyethyl acrylate and itaconic anhydride - a monomer derived from renewable resources - is carried out in a controlled fashion. The copolymer allows preparation of gold nanoparticles with abundant surficial carboxyl and alkyne functional groups that are dendronized via Cu(I)-mediated "click" reaction. PMID:23588100

  2. 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.

  3. [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

  4. Phase inversion of ionomer-stabilized emulsions to form high internal phase emulsions (HIPEs).

    PubMed

    Zhang, Tao; Xu, Zhiguang; Cai, Zengxiao; Guo, Qipeng

    2015-06-28

    Herein, we report the phase inversion of ionomer-stabilized emulsions to form high internal phase emulsions (HIPEs) induced by salt concentration and pH changes. The ionomers are sulfonated polystyrenes (SPSs) with different sulfonation degrees. The emulsion types were determined by conductivity measurements, confocal microscopy and optical microscopy, and the formation of HIPE organogels was verified by the tube-inversion method and rheological measurements. SPSs with high sulfonation degrees (water-soluble) and low sulfonation degrees (water-insoluble) can stabilize oil-in-water emulsions; these emulsions were transformed into water-in-oil HIPEs by varying salt concentrations and/or changing the pH. SPS, with a sulfonation degree of 11.6%, is the most efficient, and as low as 0.2 (w/v)% of the organic phase is enough to stabilize the HIPEs. Phase inversion of the oil-in-water emulsions occurred to form water-in-oil HIPEs by increasing the salt concentration in the aqueous phase. Two phase inversion points from oil-in-water emulsions to water-in-oil HIPEs were observed at pH 1 and 13. Moreover, synergetic effects between the salt concentration and pH changes occurred upon the inversion of the emulsion type. The organic phase can be a variety of organic solvents, including toluene, xylene, chloroform, dichloroethane, dichloromethane and anisole, as well as monomers such as styrene, butyl acrylate, methyl methacrylate and ethylene glycol dimethacrylate. Poly(HIPEs) were successfully prepared by the polymerization of monomers as the continuous phase in the ionomer-stabilized HIPEs. PMID:26028420

  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. PMID:24675994

  6. Atom Transfer Radical Copolymerization of Gradient Copolymers of HEMA/DMAEMA with Arbitrary Composition Profiles

    NASA Astrophysics Data System (ADS)

    Gallow, Keith; Loo, Yueh-Lin

    2009-03-01

    Gradient copolymers represent a new class of statistical copolymers where a non-uniform composition profile is controllably introduced along the length of the polymer chain. Gradient copolymers have thermal and mechanical properties that are different from random or block copolymers having the same average composition. Due to synthetic limitations, however, the introduction of arbitrary composition profiles remains challenging. Here, we demonstrate the ability to controllably introduce arbitrary composition profiles along copolymers of 2-hydroxyethyl methacrylate (HEMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) by atom transfer radical copolymerization in a semi-batch reactor. Using gas chromatography to monitor monomer consumption, we have constructed a kinetic model which we use as a basis to synthesize copolymers with linear and parabolic composition profiles. The overall DMAEMA content and molecular weight of these gradient copolymers were determined using nuclear magnetic resonance spectroscopy and size exclusion chromatography, respectively, and both show good agreement with our model's predictions.

  7. 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

  8. 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

  9. Surface Modification of PET Fabric by Graft Copolymerization with Acrylic Acid and Its Antibacterial Properties

    PubMed Central

    Abdolahifard, M.; Bahrami, S. Hajir; Malek, R. M. A.

    2011-01-01

    Graft copolymerization of acrylic acid (AA) onto Poly(ethylene terephthalate) (PET) fabrics with the aid of benzoyl peroxide was carried out. The effect of polymerization parameters on the graft yield was studied. Percent grafting was enhanced significantly by increasing benzoyl peroxide (BP) concentrations up to 3.84 g/lit and then decreased upon further increase in initiator concentration. Preswelling of PET leads to changes in its sorption-diffusion properties and favors an increase in the degree of grafting. The antibiotics treated grafted fabrics showed antibacterial properties towards gram-positive and gram-negative microorganisms. FTIR and SEM were used to characterize AA-grafted polyester fabrics. PMID:24052819

  10. Radiation dosimetry and spectrometry with superheated emulsions

    NASA Astrophysics Data System (ADS)

    d'Errico, Francesco

    2001-09-01

    Detectors based on emulsions of overexpanded halocarbon droplets in tissue equivalent aqueous gels or soft polymers, known as "superheated drop detectors" or "bubble (damage) detectors", have been used in radiation detection, dosimetry and spectrometry for over two decades. Recent technological advances have led to the introduction of several instruments for individual and area monitoring: passive integrating meters based on the optical or volumetric registration of the bubbles, and active counters detecting bubble nucleations acoustically. These advances in the instrumentation have been matched by the progress made in the production of stable and well-specified emulsions of superheated droplets. A variety of halocarbons are employed in the formulation of the detectors, and this permits a wide range of applications. In particular, halocarbons with a moderate degree of superheat, i.e. a relatively small difference between their operating temperature and boiling point, can be used in neutron dosimetry and spectrometry since they are only nucleated by energetic heavy ions such as those produced by fast neutrons. More recently, halocarbons with an elevated degree of superheat have been utilised to produce emulsions that nucleate with much smaller energy deposition and detect low linear energy transfer radiations, such as photons and electrons. This paper reviews the detector physics of superheated emulsions and their applications in radiation measurements, particularly in neutron dosimetry and spectrometry.

  11. 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.

  12. Probing Interfacial Emulsion Stability Controls using Electrorheology

    NASA Astrophysics Data System (ADS)

    Wang, Xiuyu; Brandvik, Amy; Alvarado, Vladimir

    2010-11-01

    The stability of water-in-oil emulsions is controlled by interfacial mechanisms that include oil film rheology of approaching drops and the strength of drop interfaces. Film drainage is mainly a function of the continuous phase rheology. Temperature is used to regulate the viscosity of the continuous phase and hence determine its effect on emulsion stability through film drainage, in contrast with interfacial strength. In this study, one crude oil is used to formulate water-in-oil emulsions. Oil-water interfacial tension is measured to gauge other interfacial changes with temperature. The critical field value, used as proxy of emulsion stability, approaches a plateau value for each crude oil- aqueous solution pair, at sufficiently high temperature (50 ^oC), which is interpreted to reflect the intrinsic drop-coating film resistance to coalescence. Interfacial tension does vary significantly with either aqueous phase composition or temperature. From comparison with previous results, we speculate that drop coating film is composed of a fraction of asphaltic compunds.

  13. Nuclear Emulsion - Skylab Experiment S009

    NASA Technical Reports Server (NTRS)

    1970-01-01

    This photograph shows Skylab's Nuclear Emulsion experiment, a Skylab science facility that was mounted inside the Multiple Docking Adapter used to record the relative abundance of primary, high-energy heavy nuclei outside the Earth's atmosphere. The Marshall Space Flight Center had program management responsibility for the development of Skylab hardware and experiments.

  14. 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

  15. 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. PMID:18992799

  16. 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

  17. [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

  18. 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.

  19. 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.

  20. 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

  1. Emulsion properties of casein and whey protein hydrolysates and the relation with other hydrolysate characteristics.

    PubMed

    van der Ven, C; Gruppen, H; de Bont, D B; Voragen, A G

    2001-10-01

    Casein and whey protein were hydrolyzed using 11 different commercially available enzyme preparations. Emulsion-forming ability and emulsion stability of the digests were measured as well as biochemical properties with the objective to study the relations between hydrolysate characteristics and emulsion properties. All whey protein hydrolysates formed emulsions with bimodal droplet size distributions, signifying poor emulsion-forming ability. Emulsion-forming ability of some casein hydrolysates was comparable to that of intact casein. Emulsion instability was caused by creaming and coalescence. Creaming occurred mainly in whey hydrolysate emulsions and in casein hydrolysate emulsions containing large emulsion droplets. Coalescence was dominant in casein emulsions with a broad particle size distribution. Emulsion instability due to coalescence was related to apparent molecular weight distribution of hydrolysates; a relative high amount of peptides larger than 2 kDa positively influences emulsion stability. PMID:11600059

  2. Crocin loaded nano-emulsions: Factors affecting emulsion properties in spontaneous emulsification.

    PubMed

    Mehrnia, Mohammad-Amin; Jafari, Seid-Mahdi; Makhmal-Zadeh, Behzad S; Maghsoudlou, Yahya

    2016-03-01

    Spontaneous emulsification may be used for encapsulating bioactive compounds in food and pharmaceutical industry. It has several advantages over high energy and other low energy methods including, protecting sensitive compounds against severe conditions of high energy method and its ability to minimize surfactant, removal of cosurfactant and thermal stability compared with other low energy methods. In this study, we examined possibility of encapsulating highly soluble crocin in W/O micro-emulsions using spontaneous method which further could be used for making double emulsions. Nonionic surfactants of Span 80 and polyglycerol polyricinoleate (PGPR) were used for making micro-emulsions that showed the high potential of PGPR for spontaneous method. Surfactant to water ratio (SWR%) was evaluated to find the highest amount of aqueous phase which can be dispersed in organic phase. Droplet size decreased by increasing SWR toward the SWR=100% which had the smallest droplet size and then increased at higher levels of surfactant. By increasing SWR, shear viscosity increased which showed the high effect of PGPR on rheological properties. This study shows in addition to W/O micro-emulsions, spontaneous method could be used for preparing stable O/W micro-emulsions. PMID:26708427

  3. 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

  4. 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

  5. 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

    2014-01-01

    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. PMID:24988188

  6. 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

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

    PubMed

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

    2014-01-01

    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

  8. 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

  9. 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

  10. OPERA experiment and its releted emulsion techniques

    SciTech Connect

    Ariga, Akitaka

    2008-02-21

    The OPERA experiment is designed to clarify neutrino oscillation by detecting appearance of {nu}{sub {tau}} in pure {nu}{sub {mu}} beam through a long baseline method (CNGS beam from cern to the Gran Sasso laboratory). The key technique is the use of emulsion films and their scanning. We developed a new high speed scanning system with speed of 50 cm{sup 2}/h and it was successfully demonstrated in 2006 CNGS commissioning. The new scanning system is not only meant for the OPERA experiment, but it has large potential of applications. For example, measurement of {nu}{sub e} with strong separation power against {pi}{sup 0}. Or a compact emulsion spectrometer for future neutrino experiments.

  11. Swelling and thermodynamic studies of temperature responsive 2-hydroxyethyl methacrylate/itaconic acid copolymeric hydrogels prepared via gamma radiation

    NASA Astrophysics Data System (ADS)

    Tomić, Simonida L. J.; Mićić, Maja M.; Filipović, Jovanka M.; Suljovrujić, Edin H.

    2007-08-01

    The copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were synthesized by gamma radiation induced radical polymerization. Swelling and thermodynamic properties of PHEMA and copolymeric P(HEMA/IA) hydrogels with different IA contents (2, 3.5 and 5 mol%) were studied in a wide pH and temperature range. Initial studies of so-prepared hydrogels show interesting pH and temperature sensitivity in swelling and drug release behavior. Special attention was devoted to temperature investigations around physiological temperature (37 °C), where small changes in temperature significantly influence swelling and drug release of these hydrogels. Due to maximum swelling of hydrogels around 40 °C, the P(HEMA/IA) hydrogel containing 5 mol% of IA without and with drug-antibiotic (gentamicin) were investigated at pH 7.40 and in the temperature range 25-42 °C, in order to evaluate their potential for medical applications.

  12. Emulsions Containing Perfluorocarbon Support Cell Cultures

    NASA Technical Reports Server (NTRS)

    Ju, Lu-Kwang; Lee, Jaw Fang; Armiger, William B.

    1990-01-01

    Addition of emulsion containing perfluorocarbon liquid to aqueous cell-culture medium increases capacity of medium to support mammalian cells. FC-40 Fluorinert (or equivalent) - increases average density of medium so approximately equal to that of cells. Cells stay suspended in medium without mechanical stirring, which damages them. Increases density enough to prevent cells from setting, and increases viscosity of medium so oxygen bubbled through it and nutrients stirred in with less damage to delicate cells.

  13. 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.

  14. Large area emulsion chamber experiments for the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Parnell, T. A.

    1985-01-01

    Emulsion-chamber experiments employing nuclear-track emulsions, etchable plastic detectors, metal plates, and X-ray films continue to demonstrate high productivity and potential in the study of cosmic-ray primaries and their interactions. Emulsions, with unsurpassed track-recording capability, provide an appropriate medium for the study of nucleus-nucleus interactions at high energy, which will likely produce observations of a phase change in nuclear matter. The many advantages of emulsion chambers (excellent multitrack recording capability, large geometry factor, low apparatus cost, simplicity of design and construction) are complemented by the major advantages of the Space Shuttle as an experiment carrier. A Shuttle experiment which could make a significant advance in both cosmic-ray primary and nucleus-nucleus interaction studies is described. Such an experiment would serve as a guide for use of emulsions during the Space Station era. Some practical factors that must be considered in planning a Shuttle exposure of emulsion chambers are discussed.

  15. Lipase-catalyzed synthesis of aliphatic polyesters via copolymerization of lactone, dialkyl diester, and diol.

    PubMed

    Jiang, Zhaozhong

    2008-11-01

    Candida antarctica lipase (CALB) has been successfully used as catalyst for copolymerization of dialkyl diester with diol and lactone to form aliphatic polyesters. The polymerization reactions were performed using a two stage process: first stage oligomerization under low vacuum followed by second stage polymerization under high vacuum. Use of the two-stage process is required to obtain products with high molecular weights at high yields for the following reasons: (i) the first stage reaction ensures that the monomer loss via evaporation is minimized to maintain 1:1 diester to diol stoichiometric ratio, and the monomers are converted to nonvolatile oligomers; (ii) use of high vacuum during the second stage accelerates equilibrium transesterification reactions to transform the oligomers to high molecular weight polymers. Thus, terpolymers of omega-pentadecalactone (PDL), diethyl succinate (DES), and 1,4-butanediol (BD) with a M w of whole product (nonfractionated) up to 77000 and M w/ M n between 1.7 and 4.0 were synthesized in high yields (e.g., 95% isolated yield). A desirable reaction temperature for the copolymerizations was found to be around 95 degrees C. At 1:1:1 PDL/DES/BD monomer molar ratio, the resultant terpolymers contained equal moles of PDL, succinate, and butylene repeat units in the polymer chains. (1)H and (13)C NMR analyses were used to determine the polyester microstructures. The synthesized PDL-DES-BD terpolymers possessed near random structures with all possible combinations of PDL, succinate, and butylene units via ester linkages in the polymer backbone. Furthermore, thermal stability and crystallinity of a pure PDL-DES-BD terpolymer with 1:1:1 PDL to succinate to butylene unit ratio and M w of 85400 were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The copolyester was found to be a semicrystalline material with a T g of -34 degrees C and a T m of 64 degrees C, which degrades in a single weight loss

  16. [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

  17. 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.

  18. Lipid Emulsion for Local Anesthetic Systemic Toxicity

    PubMed Central

    Ciechanowicz, Sarah; Patil, Vinod

    2012-01-01

    The accidental overdose of local anesthetics may prove fatal. The commonly used amide local anesthetics have varying adverse effects on the myocardium, and beyond a certain dose all are capable of causing death. Local anesthetics are the most frequently used drugs amongst anesthetists and although uncommon, local anaesthetic systemic toxicity accounts for a high proportion of mortality, with local anaesthetic-induced cardiac arrest particularly resistant to standard resuscitation methods. Over the last decade, there has been convincing evidence of intravenous lipid emulsions as a rescue in local anesthetic-cardiotoxicity, and anesthetic organisations, over the globe have developed guidelines on the use of this drug. Despite this, awareness amongst practitioners appears to be lacking. All who use local anesthetics in their practice should have an appreciation of patients at high risk of toxicity, early symptoms and signs of toxicity, preventative measures when using local anesthetics, and the initial management of systemic toxicity with intravenous lipid emulsion. In this paper we intend to discuss the pharmacology and pathophysiology of local anesthetics and toxicity, and the rationale for lipid emulsion therapy. PMID:21969824

  19. Method for purifying solids-stabilized emulsions

    SciTech Connect

    Knowlton, H.E.

    1987-08-25

    A method is described for purifying oil contaminated with both solids and water capable of forming a solids-stabilized emulsion layer which comprises: (a) settling the contaminated oil essentially without agitation in a first vessel, at a temperature of between 50/sup 0/C and 95/sup 0/C, to form an upper partially purified oil layer, an intermediate first oil cuff layer including a solids-stabilized emulsion of oil and 5 to 80 weight percent of solids and water, and a lower first water layer, and withdrawing water from the first water layer; (b) settling the partially purified oil essentially without agitation in a second vessel, at a temperature of between 50/sup 0/C and 95/sup 0/C, to form an upper purified oil layer, an intermediate second oil cuff layer including a solids-stabilized emulsion of oil and 5 to 80 weight percent of solids and water, and a lower second water layer, and providing purified oil containing not more than 2 weight percent of solids and water from the purified oil layer; and (c) settling the intermediate first and second oil cuff layers essentially without agitation in a third vessel, at a temperature between 50/sup 0/C and 95/sup 0/C , to form an upper layer including oil and 5 to 80 weight percent of solids and water and a lower third water layer.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. Homo- and co-polymerization of polysytrene-block-poly(acrylic acid)-coated metal nanoparticles.

    PubMed

    Wang, Hong; Song, Xiaohui; Liu, Cuicui; He, Jiating; Chong, Wen Han; Chen, Hongyu

    2014-08-26

    Amphiphilic block copolymers such as polystyrene-block-poly(acrylic acid) (PSPAA) give micelles that are known to undergo sphere-to-cylinder shape transformation. Exploiting this polymer property, core-shell nanoparticles coated in PSPAA can be "polymerized" into long chains following the chain-growth polymerization mode. This method is now extended to include a variety of different nanoparticles. A case study on the assembly process was carried out to understand the influence of the PAA block length, the surface ligand, and the size and morphology of the monomer nanoparticles. Shortening the PAA block promotes the reorganization of the amphiphilic copolymer in the micelles, which is essential for assembling large Au nanoparticles. Small Au nanoparticles can be directly "copolymerized" with empty PSPAA micelles into chains. The reaction time, acid quantity, and the [Au nanoparticles]/[PSPAA micelles] concentration ratio played important roles in controlling the sphere-cylinder-vesicle conversion of the PSPAA micelles, giving rise to different kinds of random "copolymers". With this knowledge, a general method is then developed to synthesize homo, random, and block "copolymers", where the basic units include small Au nanoparticles (d = 16 nm), large Au nanoparticles (d = 32 nm), Au nanorods, Te nanowires, and carbon nanotubes. Given the lack of means for assembling nanoparticles, advancing synthetic capabilities is of crucial importance. Our work provides convenient routes for combining nanoparticles into long-chain structures, facilitating rational design of complex nanostructures in the future. PMID:25000121

  5. 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

  6. 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.

  7. Double inversion of emulsions induced by salt concentration.

    PubMed

    Zhang, Jingchun; Li, Lu; Wang, Jun; Sun, Haigang; Xu, Jian; Sun, Dejun

    2012-05-01

    The effects of salt on emulsions containing sorbitan oleate (Span 80) and Laponite particles were investigated. Surprisingly, a novel double phase inversion was induced by simply changing the salt concentration. At fixed concentration of Laponite particles in the aqueous phase and surfactant in paraffin oil, emulsions are oil in water (o/w) when the concentration of NaCl is lower than 5 mM. Emulsions of water in oil (w/o) are obtained when the NaCl concentration is between 5 and 20 mM. Then the emulsions invert to o/w when the salt concentration is higher than 50 mM. In this process, different emulsifiers dominate the composition of the interfacial layer, and the emulsion type is correspondingly controlled. When the salt concentration is low in the aqueous dispersion of Laponite, the particles are discrete and can move to the interface freely. Therefore, the emulsions are stabilized by particles and surfactant, and the type is o/w as particles are in domination. At intermediate salt concentrations, the aqueous dispersions of Laponite are gel-like, the viscosity is high, and the transition of the particles from the aqueous phase to the interface is inhibited. The emulsions are stabilized mainly by lipophilic surfactant, and w/o emulsions are obtained. For high salt concentration, flocculation occurs and the viscosity of the dispersion is reduced; thus, the adsorption of particles is promoted and the type of emulsions inverts to o/w. Laser-induced fluorescent confocal micrographs and cryo transmission electron microscopy clearly confirm the adsorption of Laponite particles on the surface of o/w emulsion droplets, whereas the accumulation of particles at the w/o emulsion droplet surfaces was not observed. This mechanism is also supported by the results of rheology and interfacial tension measurements. PMID:22475400

  8. 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.

  9. Glycosylated polyacrylate nanoparticles by emulsion polymerization.

    PubMed

    Abeylath, Sampath C; Turos, Edward

    2007-08-01

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

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

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 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. 21 CFR 524.802 - Enrofloxacin, silver sulfadiazine emulsion.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 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 §...

  12. 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 §...

  13. 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 §...

  14. Oilfield solids and water-in-oil emulsion stability.

    PubMed

    Sztukowski, Danuta M; Yarranton, Harvey W

    2005-05-15

    Model water-in-hydrocarbon emulsions consisting of toluene, heptane, water, asphaltenes, and native solids were used to investigate the role of native solids in the stability of oilfield emulsions. The solids were recovered from an oil-sands bitumen, a wellhead emulsion, and a refinery slop oil. The solids were clay platelets and fell into two size categories: (1) fine solids 50 to 500 nm in diameter and (2) coarse solids 1 to 10 microm in diameter. Emulsions stabilized by fine solids and asphaltenes were most stable at a 2:1 fractional area ratio of asphaltenes to solids. It appears that when the asphaltene surface coverage is high, insufficient solids remain to make an effective barrier. When the solids coverage is high, insufficient asphaltenes remain on the interface to immobilize the solids. Treatments that weaken the interface, such as toluene dilution, are recommended for emulsions stabilized by fine solids. Emulsions stabilized by coarse solids were unstable at low solids concentrations but became very stable at solids concentrations greater than 10 kg/m(3). At low concentrations, these solids may act as bridges between water droplets and promote coalescence. At high concentrations, layers of coarse solids may become trapped between water droplets and prevent coalescence. Treatments that flocculate the solids, such as heptane dilution, are recommended for emulsions stabilized by high concentrations of coarse solids. It is possible that emulsions containing both types of solids may require more than one treatment, or even process step, for effective water resolution. PMID:15837502

  15. 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.

  16. 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.

  17. Emulsion design to improve the delivery of functional lipophilic components.

    PubMed

    McClements, David Julian

    2010-01-01

    The food industry has used emulsion science and technology for many years to create a diverse range of food products, such as milk, cream, soft drinks, nutritional beverages, dressings, mayonnaise, sauces, dips, deserts, ice cream, margarine, and butter. The majority of these food products are conventional oil-in-water (O/W) or water-in-oil (W/O) type emulsions. Recently, there has been increasing interest within the food industry in either improving or extending the functional performance of foods using novel structured emulsions. This article reviews recent developments in the creation of structured emulsions that could be used by the food and other industries, including nanoemulsions, multiple emulsions, multilayer emulsions, solid lipid particles, and filled hydrogel particles. These structured emulsions can be produced from food-grade [generally recognized as safe (GRAS)] ingredients (e.g., lipids, proteins, polysaccharides, surfactants, and minerals), using simple processing operations (e.g., mixing, homogenizing, and thermal processing). The structure, production, performance, and potential applications of each type of structured emulsion system are discussed. PMID:22129337

  18. Silicone oil emulsions stabilized by polymers and solid particles.

    PubMed

    Kawaguchi, Masami

    2016-07-01

    Silicone oil emulsions stabilized by various emulsifiers such as polymers, solid particles alone, and solid particles with pre-adsorbed surfactants or polymers are reviewed, focusing on their emulsion stability and rheological properties as a function of the emulsifier concentration. An increase in the concentration of the emulsifier leads to a decrease in the droplet size and an increase in the emulsion stability, irrespective of the emulsifier. Moreover, the overlapping concentration of polymer can be regarded as a criterion for the preparation of emulsions using polymeric emulsifiers. Changes in the emulsion stability and rheological responses of the emulsions prepared by the solid particles with pre-adsorbed polymers are discussed in terms of the amounts of the emulsifiers adsorbed. For emulsions prepared from hydrophilic silica particles with pre-adsorbed polymers, a decrease in the droplet size of an order of magnitude can be controlled by an increase in the concentration of polymer, whereas hydrophilic silica particles alone cannot produce stable silicone oil emulsions. PMID:26170165

  19. 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.

  20. 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.

  1. 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...

  2. 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.

  3. 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

  4. 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...

  5. 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

  6. [Effect of lipid emulsifiers on the properties of organoperfluorine emulsions].

    PubMed

    Oksinoĭd, O E; Romanova, M Zh; Afonin, N I

    1990-01-01

    The preparation and application of a new type of organoperfluorine (OPF) emulsions with lipids serving as emulsifiers, their biological and physicochemical properties are discussed. The first-generation emulsions with the nonionic emulsifier, ethylene and propylene oxide blockpolymer, were found to be complementary active and to affect the system's biological properties. Interactions between OPF and phospholipids are analysed. The compositions of the new type OPF emulsions are given, of which perfluoroctyl bromide and perfluoromethyl adamantine emulsions are shown to be currently of most interest, since they are stable at room temperature and exhibit somewhat superior physicochemical and biological parameters. A conclusion is derived that the developed lipid-based OPF emulsions have good clinical prospects. PMID:2275276

  7. Simulation of Non-Newtonian Emulsion Flows in Microchannels

    NASA Astrophysics Data System (ADS)

    Malanichev, I. V.; Akhmadiev, F. G.

    2015-11-01

    Simulation of emulsion flows in differently shaped microchannels to reproduce the choking of such flows as a result of the effect of dynamic blocking has been made. A model of a highly concentrated emulsion as a structure of tightly packed deformed droplets surrounded by elastic shells is considered. The motion of liquid was determined by the method of the lattice Boltzmann equations together with the immersed boundary method. The influence of the non-Newtonian properties and of elastic turbulence of the indicated emulsion, as well as of the elasticity of the shells of its droplets and of the interaction of these shells on the emulsion motion in a microchannel, has been investigated. It is shown that the flow of this emulsion can be slowed down substantially only due to the mutual attraction of the shells of its droplets.

  8. 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)

  9. 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.

  10. ESR studies of semicontinuous emulsion polymerization

    SciTech Connect

    Lau, W.; Westmoreland, D.G.

    1993-12-31

    Electron spin resonance (ESR) is used in the detection and quantification of propagating radicals during a semicontinuous emulsion polymerization. The propagating radical concentration is crucial for the determination of kinetic parameters of the emulsion polymerization process. A flow reactor was built which involves a closed-loop flow system that circulates latex from the polymerization reactor through the ESR cavity for free-radical measurements and back to the reactor. With the continuous measurement of the radical concentrations during a polymerization of methyl methacrylate (MMA), {bar n} (average number of radicals per particle) and k{sub p} (propagating rate constant), are measured throughout the entire polymerization. For the polymerization of the MMA system studied, the authors observed a gradual increased in n and decrease in k{sub p} during the run, suggesting a diffusionally controlled process and that the polymerization is not occurring homogeneously throughout the polymer particles. In the glassy pMMA matrix, radicals can be {open_quotes}trapped{close_quotes} within a minimum volume and remain unterminated.

  11. Ultraviolet photoinitiated on-fiber copolymerization of ionic liquid sorbent coatings for headspace and direct immersion solid-phase microextraction.

    PubMed

    Ho, Tien D; Yu, Honglian; Cole, William T S; Anderson, Jared L

    2012-11-01

    A high-throughput method for the production of solid-phase microextraction (SPME) sorbent coatings via ultraviolet (UV) photoinitiated copolymerization of ionic liquid (IL) monomers on a fused silica support is described. The copolymerization of monocationic and dicationic IL cross-linkers was performed "on-fiber" using UV initiated free radical polymerization. Mixtures composed of various amounts of the IL cross-linker, UV initiator (DAROCUR 1173), and IL monomer were dip-coated onto an etched and derivatized fused silica support and placed in a high-capacity UV reactor. The method requires no organic dispersive solvent and is much more rapid compared to traditional methods in which polymeric ionic liquid (PIL) sorbent coatings are prepared by 2,2'-azobis(2-methylpropionitrile) (AIBN)-initiated polymerization. Two ionic liquid-based cross-linkers, namely, 1,8-di (3-vinylimidazolium) octane dibromide ([(VIM)(2)C(8)] 2[Br]) and 1,12-di (3-vinylimidazolium) dodecane dibromide ([(VIM)(2)C(12)] 2[Br]), were copolymerized with an ionic liquid monomer, 1-vinyl-3-hexylimidazolium chloride ([VHIM][Cl]), to produce polar cross-linked PIL-based SPME sorbent coatings. The cross-linking and immobilization of these coatings make them particularly applicable in direct immersion SPME. The coatings were applied in the extraction of polar analytes, including alcohols, aldehydes, and esters, from aqueous solutions using headspace and direct immersion SPME gas chromatography mass spectrometry (GC/MS). Compared to linear PIL-based sorbent coatings containing the same anions, the cross-linked PIL-based coatings exhibited higher thermal stability and lower bleed, making them ideal for GC/MS. Recovery experiments were performed in deionized, well, and river water. The structural integrity of the sorbent coatings, as well as their analytical precision, was not diminished after 90 extractions from complex samples using headspace and direct immersion SPME. PMID:22991947

  12. Ring-opening copolymerization of maleic anhydride with epoxides: a chain-growth approach to unsaturated polyesters.

    PubMed

    DiCiccio, Angela M; Coates, Geoffrey W

    2011-07-20

    We report the ring-opening copolymerization of maleic anhydride with a variety of epoxides catalyzed by a chromium(III) salen complex. Quantitative isomerization of the cis-maleate form of all polymers affords the trans-fumarate analogues. Addition of chain transfer reagents yields low M(n), narrow PDI polymer samples. This method provides access to a range of new unsaturated polyesters with versatile functionality, as well as the first synthesis of high molecular weight poly(propylene fumarate). PMID:21699247

  13. 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.

  14. Research of inverted emulsions properties on the base of new emulsifiers

    NASA Astrophysics Data System (ADS)

    Minaev, K.; Epikhin, A.; Novoseltsev, D.; Andropov, M.; Yanovsky, V.; Ulyanova, O.

    2014-08-01

    Emulsifiers on the base of tallol and ethanolamines derived acids have been researched in the paper. Electrical stability of emulsions drilling muds has been investigated. It is proved that synthesized emulsifiers according to emulsion stability can be divided into two groups. The first group is emulsifiers with high initial electrical stability but low emulsion stability under long-term storing, and the second group is emulsifiers with low electrical stability but with high emulsion stability. Emulsions flow characteristics have been researched. It is established that emulsifier on the base of ethanolamine provides better emulsion characteristics for drilling muds emulsions.

  15. 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

  16. Stability of drug-carrier emulsions containing phosphatidylcholine mixtures.

    PubMed

    Trotta, Michele; Pattarino, Franco; Ignoni, Terenzio

    2002-03-01

    Lipid emulsion particles containing 10% of medium chain triglycerides were prepared using 2% w/w of a mixture 1:1 w/w of purified soya phosphatidylcholine and 2-hexanoyl phosphatidylcholine as emulsifier mixture, for use as drug carriers. The mean droplet sizes of emulsions, prepared using an Ultra Turrax or a high-pressure homogenizer, were about 288 and 158 nm, respectively, compared with 380 and 268 nm for emulsions containing lecithin, or 325 and 240 nm for those containing 6-phosphatidylcholine. The stability of the emulsions, determined by monitoring the decrease of a lipophilic marker at a specified level within the emulsion, and observing coalescence over time, was also greatly increased using the emulsifier mixture. The emulsion stability did not notably change in the presence of a model destabilizing drug, indomethacin. The use of a second hydrophilic surfactant to adjust the packing properties of the lecithin at the oil-water interface provided an increase in the stability of lipid emulsions, and this may be of importance in the formulation of drug delivery systems. PMID:11880004

  17. Synergistic effect on corrosion resistance of Phynox substrates grafted with surface-initiated ATRP (co)polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2-hydroxyethyl methacrylate (HEMA).

    PubMed

    Barthélémy, Bastien; Maheux, Simon; Devillers, Sébastien; Kanoufi, Frédéric; Combellas, Catherine; Delhalle, Joseph; Mekhalif, Zineb

    2014-07-01

    Phynox is of high interest for biomedical applications due to its biocompatibility and corrosion resistance. However, some Phynox applications require specific surface properties. These can be imparted with suitable surface functionalizations of its oxide layer. The present work investigates the surface-initiated atom transfer radical polymerization (ATRP) of 2-methacryloyoxyethyl phosphorylcholine (MPC), 2-hydroxyethyl methacrylate (HEMA), and ATRP copolymerization of (HEMA-co-MPC) (block and statistic copolymerization with different molar ratios) on grafted Phynox substrates modified with 11-(2-bromoisobutyrate)-undecyl-1-phosphonic acid (BUPA) as initiator. It is found that ATRP (co)polymerization of these monomers is feasible and forms hydrophilic layers, while improving the corrosion resistance of the system. PMID:24915233

  18. 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. PMID:26549699

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. Protein Formulations for Emulsions and Solid-in-Oil Dispersions.

    PubMed

    Martins, Madalena; Loureiro, Ana; Azoia, Nuno G; Silva, Carla; Cavaco-Paulo, Artur

    2016-06-01

    Needs from medical and cosmetic areas have led to the design of novel nanosized emulsions and solid-in-oil dispersions of proteins. Here, we describe the production of those emulsions and dispersions using high-energy methodologies such as high-pressure homogenization or ultrasound. Recent work has resulted in new mechanistic insights related to the formation of protein emulsions and dispersions. The production method and composition of these formulations can determine major parameters such as size, stability, and functionality, and therefore their final application. Aqueous nanoemulsions of proteins can be used for drug delivery, while solid-in-oil dispersions are often used in transdermal applications. PMID:26996614

  4. Rheology and microstructure of magmatic emulsions - Theory and experiments

    NASA Technical Reports Server (NTRS)

    Stein, Daniel J.; Spera, Frank J.

    1992-01-01

    The rheological properties of a dilute mixture of melt plus vapor bubbles, referred to as emulsion, are investigated theoretically and in rheometric experiments on dilute viscous germanium dioxide emulsions at temperatures between 1100 and 1175 C and at 100 kPa pressure in a rotating rod rheometer at shear rates between 0.05/s and 7/s. The results indicate that the emulsions may be described by a power-law constitutive relation when observations cover a sufficient range of shear rates to resolve nonlinear flow.

  5. 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.

  6. Electromagnetic Shower Reconstruction in Emulsion Cloud Chamber

    NASA Astrophysics Data System (ADS)

    Esposito, L. S.

    2006-04-01

    Atmospheric neutrino data from the MACRO, Soudan II and Super-Kamiokande experiments are consistent with the hypothesis of νμ → ντ oscillations. The OPERA experiment aims to prove definitively this hypothesis with the direct observation of ντ neutrinos in the νμ beam produced at CERN (CNGS). The apparatus, in construction at the Gran Sasso Underground Laboratory, is equipped with electronic detectors and a sensitive target. The target is highly segmented in units, bricks, composed of alternate nuclear emulsion plates and lead sheets. An algorithm to reconstruct electromagnetic showers in a brick was developed. The algorithm was optimized using experimental data from 1, 3 and 6 GeV electron exposures and cross-checked with detailed Monte Carlo simulations. Finally, a neural network was used as electron/pion separator.

  7. 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.

  8. Process for emulsion flooding of petroleum reservoirs

    SciTech Connect

    Lepper, U.

    1984-12-18

    A process for emulsion flooding of petroleum reservoirs comprising injecting a thermodynamically stable microemulsion consisting of oil, a non-ionic surfactant and water which optionally contains salts dissolved in any desired concentrations, into an injection well; driving injected microemulsion bank through the reservoir by means of water which likewise may contain salts dissolved in any desired concentrations. The microemulsion bank in contact with the water driving the bank forms an excess phase with a high water content, a low surfactant content and low oil content, and has such a viscosity sufficient to prevent the penetration of the subsequent water into the microemulsion bank which would cause a decrease of its flowability and its ability to displace oil.

  9. 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.

  10. Wall slip and fluidity in emulsion flow

    NASA Astrophysics Data System (ADS)

    Paredes, José; Shahidzadeh, Noushine; Bonn, Daniel

    2015-10-01

    The microscopic origin of apparent wall slip is studied systematically using a confocal laser scanning microscope coupled to a rheometer. We obtain flow curves on a model emulsion from classical macroscopic measurements that are compared with flow curves obtained from microscopic measurements. By controlling the wetting properties of the shearing walls, we show that the characteristic length used in the so-called fluidity model, proposed by Goyon et al. [Nature (London) 454, 84 (2008), 10.1038/nature07026], can be understood in terms of roughness induced by adsorbed droplets on the surface. Additionally, we disentangle two different effects that contribute to the difference between micro- and macrorheology. Both effects manifest themselves as gap-dependent viscosities due to either the formation of a lubricating layer close to the shearing walls or cooperative effects when the flow is strongly confined. Finally, we show that the cooperative effects can also be translated into an effective slip velocity.

  11. Concerning the deactivation of cobalt(III)-based porphyrin and salen catalysts in epoxide/CO2 copolymerization.

    PubMed

    Xia, Wei; Salmeia, Khalifah A; Vagin, Sergei I; Rieger, Bernhard

    2015-03-01

    Functioning as active catalysts for propylene oxide (PO) and carbon dioxide copolymerization, cobalt(III)-based salen and porphyrin complexes have drawn great attention owing to their readily modifiable nature and promising catalytic behavior, such as high selectivity for the copolymer formation and good regioselectivity with respect to the polymer microstructure. Both cobalt(III)-salen and porphyrin catalysts have been found to undergo reduction reactions to their corresponding catalytically inactive cobalt(II) species in the presence of propylene oxide, as evidenced by UV/Vis and NMR spectroscopies and X-ray crystallography (for cobalt(II)-salen). Further investigations on a TPPCoCl (TPP = tetraphenylporphyrin) and NaOMe system reveal that such a catalyst reduction is attributed to the presence of alkoxide anions. Kinetic studies of the redox reaction of TPPCoCl with NaOMe suggests a pseudo-first order in cobalt(III)-porphyrin. The addition of a co-catalyst, namely bis(triphenylphosphine)iminium chloride (PPNCl), into the reaction system of cobalt(III)-salen/porphyrin and PO shows no direct stabilizing effect. However, the results of PO/CO2 copolymerization by cobalt(III)-salen/porphyrin with PPNCl suggest a suppressed catalyst reduction. This phenomenon is explained by a rapid transformation of the alkoxide into the carbonate chain end in the course of the polymer formation, greatly shortening the lifetime of the autoreducible PO-ring-opening intermediates, cobalt(III)-salen/porphyrin alkoxides. PMID:25656829

  12. Purification of polar compounds from Radix isatidis using conventional C18 column coupled with polar-copolymerized C18 column.

    PubMed

    Zeng, Jing; Guo, Zhimou; Xiao, Yuansheng; Wang, Chaoran; Zhang, Xiuli; Liang, Xinmiao

    2010-11-01

    Regarding hydrophilic interaction chromatography and normal phase liquid chromatography, RPLC is another choice used to separate polar compounds with the improvement of polar-modified C18 stationary phase. In this study, a method using conventional C18 column coupled with polar-copolymerized C18 column was successfully developed for the separation and purification of polar compounds from Radix isatidis, which is one of the most commonly used traditional Chinese medicines (TCMs). An XTerra MS C18 column was used to fractionate the extract of R. isatidis and a homemade polar-copolymerized C18 column was utilized for the final purification due to its good separation selectivity and high resolution for polar compounds. The established purification system demonstrated good orthogonality for the polar compounds. As a result, ten compounds were purified and three of them were identified as 3-methyl-5-vinyloxazolidin-2-one (compound A), 5-hydroxymethyl-2-furaldehyde (compound B) and 3-methylfuran-2-carboxylic acid (compound G) based on the MS, IR and extensive NMR data, respectively. It was demonstrated to be a feasible and powerful technique for the purification of polar compounds under RPLC mode and more chemical information of TCMs will be obtained to interpret the efficiency of TCMs. PMID:20886519

  13. Physical chemistry of highly concentrated emulsions.

    PubMed

    Foudazi, Reza; Qavi, Sahar; Masalova, Irina; Malkin, Alexander Ya

    2015-06-01

    This review explores the physics underlying the rheology of highly concentrated emulsions (HCEs) to determine the relationship between elasticity and HCE stability, and to consider whether it is possible to describe all physicochemical properties of HCEs on the basis of a unique physical approach. We define HCEs as emulsions with a volume fraction above the maximum closest packing fraction of monodisperse spheres, φm=0.74, even if droplets are not of polyhedron shape. The solid-like rheological behavior of HCEs is characterized by yield stress and elasticity, properties which depend on droplet polydispersity and which are affected by caging at volume fractions about the jamming concentration, φj. A bimodal size distribution in HCEs diminishes caging and facilitates droplet movement, resulting in HCEs with negligible yield stress and no plateau in storage modulus. Thermodynamic forces automatically move HCEs toward the lowest free energy state, but since interdroplet forces create local minimums - points beyond which free energy temporarily increases before it reaches the global minimum of the system - the free energy of HCEs will settle at a local minimum unless additional energy is added. Several attempts have been undertaken to predict the elasticity of HCEs. In many cases, the elastic modulus of HCEs is higher than the one predicted from classical models, which only take into account spatial repulsion (or simply interfacial energy). Improved models based on free energy calculation should be developed to consider the disjoining pressure and interfacial rheology in addition to spatial repulsion. The disjoining pressure and interfacial viscoelasticity, which result in the deviation of elasticity from the classical model, can be regarded as parameters for quantifying the stability of HCEs. PMID:25869114

  14. 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

  15. 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).

  16. 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

  17. Chitosan macroporous foams obtained in highly concentrated emulsions as templates.

    PubMed

    Miras, Jonathan; Vílchez, Susana; Solans, Conxita; Esquena, Jordi

    2013-11-15

    Emulsion templating is an effective route for the preparation of macroporous polymer foams, with well-defined pore structures. This kind of material is usually obtained by polymerization or crosslinking in the external phase of highly concentrated emulsions. The present article describes the synthesis of macroporous foams based on a cationic polymer, chitosan, crosslinked with genipin, a natural crosslinker. The phase behavior was used to study the influence of chitosan on surfactant self-aggregation. Hexagonal and lamellar liquid crystalline structures could be obtained in the presence of chitosan, and polymer did not greatly influence the geometric lattice parameters of these self-aggregates. O/W highly concentrated emulsions were obtained in the presence of chitosan in the continuous phase, which allowed reducing both droplet size and polydispersity. The emulsions were stable during the time required for crosslinking, obtaining macroporous foams with high pore volume and degree of crosslinking. PMID:24011788

  18. Stability and demulsification of emulsions stabilized by asphaltenes or resins.

    PubMed

    Xia, Lixin; Lu, Shiwei; Cao, Guoying

    2004-03-15

    Experimental data are presented to show the influence of asphaltenes and resins on the stability and demulsification of emulsions. It was found that emulsion stability was related to the concentrations of the asphaltene and resin in the crude oil, and the state of dispersion of the asphaltenes and resins (molecular vs colloidal) was critical to the strength or rigidity of interfacial films and hence to the stability of the emulsions. Based on this research, a possible emulsion minimization approach in refineries, which can be implemented utilizing microwave radiation, is also suggested. Comparing with conventional heating, microwave radiation can enhance the demulsification rate by an order of magnitude. The demulsification efficiency reaches 100% in a very short time under microwave radiation. PMID:14972628

  19. 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.

  20. 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

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

    PubMed

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

    2016-03-11

    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. PMID:25748819

  2. 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

  3. 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.

  4. 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.

  5. Characterization and Demulsification of Water-in-crude Oil Emulsions

    NASA Astrophysics Data System (ADS)

    Nour, Abdurahman H.; Abu Hassan, Mohd A.; Mohd Yunus, Rosli

    Many advances have been made in the field of emulsions in recent years. Emulsion behavior is largely controlled by the properties of the adsorbed layers that stabilized the oil-water surfaces. The effect of chemical demulsifiers in demulsification of water-in-crude oil emulsions were assessed experimentally. The relative rates of water separation were characterized via graduated beakers. Four groups of demulsifier with different functional groups were used in this work namely amines, polyhydric alcohol, sulphonate and polymer. The effect of alcohol addition on demulsification performance also studied. The results obtained in this study have exposed the capability of chemical demulsifiers in destabilization of water-in-crude oil emulsions. Further works are nevertheless required to provide deeper understanding of the mechanisms involved to facilitate the development of an optimum system applicable to the industry.

  6. Protective effect of polysaccharides on the stability of parenteral emulsions.

    PubMed

    Chai, Guihong; Sun, Feng; Shi, Jianli; Tian, Bin; Tang, Xing

    2013-05-01

    The main purpose of this study is to investigate the influence of two polysaccharides (dextran, hydroxyethyl starch) on the stability of parenteral emulsions. All parenteral emulsions were prepared by high-pressure homogenization. The influence of polysaccharides concentration was studied. The stabilities of autoclaving sterilization, centrifugation and freeze-thawing process were investigated extensively. Following the addition of polysaccharides, the stabilities of the parenteral emulsions were improved. A high-concentration polysaccharides solution (13%, w/v) produced better protection than a low one (1.3%, w/v), especially during freeze-thawing process. The protective mechanisms of polysaccharides were attributed to increasing systematic viscosity, non-frozen water absorbed by polysaccharides, formation of a linear bead-like structure and thicker mixed emulsifier film. Overall, polysaccharides can offer greatly increased protection for parenteral emulsions, and represent a novel protective strategy for improving the stability of this delivery system. PMID:22583006

  7. 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

  8. 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

  9. 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

  10. 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. PMID:25834923