共查询到20条相似文献,搜索用时 93 毫秒
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Menghua Li Haixia Zhang Zongxu Wu Zhenxing Zhu Xinlei Jia 《Molecules (Basel, Switzerland)》2022,27(4)
The dissipative particle dynamics simulation method is adopted to investigate the microemulsion systems prepared with surfactant (H1T1), oil (O) and water (W), which are expressed by coarse-grained models. Two topologies of O/W and W/O microemulsions are simulated with various oil and water ratios. Inverse W/O microemulsion transform to O/W microemulsion by decreasing the ratio of oil-water from 3:1 to 1:3. The stability of O/W and W/O microemulsion is controlled by shear rate, inorganic salt and the temperature, and the corresponding results are analyzed by the translucent three-dimensional structure, the mean interfacial tension and end-to-end distance of H1T1. The results show that W/O microemulsion is more stable than O/W microemulsion to resist higher inorganic salt concentration, shear rate and temperature. This investigation provides a powerful tool to predict the structure and the stability of various microemulsion systems, which is of great importance to developing new multifunctional microemulsions for multiple applications. 相似文献
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A W/O microemulsion of Tween‐80‐Span‐80/n‐butylalcohol/ethyl‐oleate/H2O to envelop insulin (INS) was prepared. In order to obtain the maximum solved water, the components of microemulsion to envelop INS were chosen with the pseudo‐ternary phase diagram and the influences of temperature, salinity as well as the pH on microemulsion areas also were investigated. To test the properties of the microemulsion, the conductance was used to divide O/W, W/O and BC regions, the dynamic light scattering to evaluate the particle diameters of microemulsion, the 125I isotope tracing method to measure the release rate of INS loaded in W/O microemulsion, and the growth inhibitory effect test to appraise the cytotoxicity on human normal cells. Results show that W/O microemulsion forms when water content below 50% in the microemulsion system. The microemulsion region decreases slightly with the increase of temperature, salinity and the decrease of pH. However, the viscosity measurements along certainly selected dilution lines to the microemulsion indicate that no phase invert occurred. Diameter of microemulsion particle increases with the addition of INS, and the increase is sharp in the first 5 days then very slightly at 68.6 nm within a month. The INS loaded W/O microemulsion possesses eminent sustaining release efficiency and the cytostatic as well as cytotoxic assays illustrate that the microemulsion can be used as drug delivery at small dosage. 相似文献
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Jingcheng Hao 《Journal of polymer science. Part A, Polymer chemistry》2001,39(19):3320-3334
Isothermal phase diagrams of the system cetyltrimethylammonium bromide (CTAB)/n‐butanol/n‐octane/water were constructed, and the effect of the oil (n‐octane) contents on the microemulsions was studied at 40 °C. We determined the microemulsion structures of two systems, CTAB/n‐butanol/10% n‐octane/water and sodium dodecyl sulfonate (As)/n‐butanol/20% styrene/water, by conductivity measurements to investigate the polymerization of acrylamide and styrene in the two microemulsion systems. The polymerization kinetics of the water‐soluble monomer acrylamide in CTAB micelles and the different CTAB/n‐butanol/10% n‐octane/water microemulsion media [water‐in‐oil (W/O), bicontinuous (BC), and oil‐in‐water (O/W)] were studied with water‐soluble sodium bisulfite as the initiator. The maximum polymerization rate in CTAB micelles was found at the second critical micelle concentration. A mechanism of polyacrylamide formation and growth was proposed. A connection between the structures of the microemulsions and the polymerization rates was observed; the maximum polymerization rate occurred at two transition points, from W/O to BC and from BC to O/W, and the polyacrylamide molecular weights, which depended on the structures of the microemulsions, were also found. A square‐root dependence of the polymerization rates on the initiator concentrations was obtained in CTAB micelles and O/W microemulsion media. The polymerization of the oil‐soluble monomer styrene in different As/n‐butanol/20% styrene/water microemulsion media (W/O, BC, and O/W) was also investigated with different initiators: water‐soluble potassium persulfate and oil‐soluble azobisisobutyronitrile. A similar connection between the structures of the microemulsions and the conversions of styrene in CTAB/n‐butanol/10% n‐octane/water for the polymerization of acrylamide was observed again. The structures of the microemulsions had an important role in the molecular weights and sizes of polystyrene. The polystyrene particles were 10–20 nm in diameter in BC microemulsion media and 30–60 nm in diameter in O/W microemulsion media according to transmission electron microscopy. We determined the solubilization site of styrene in O/W microemulsion drops by 1H NMR spectra to analyze the results of the microemulsion polymerization of styrene. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3320–3334, 2001 相似文献
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阴离子型微乳液的电导行为及其溶液结构 总被引:14,自引:0,他引:14
根据电导测量,研究了属于W/O→双连续→O/W一类微乳液的十二烷基硫酸钠(SDS)/正丁醇/辛烷/水体系的溶液结构.并探讨了表面活性剂离子对微乳液导电行为的贡献,以及表面活性剂与助表面活性剂含量、油含量对微乳液溶液结构的影响.微乳液的导电行为在W/O子区域中主要是由于SDS阴离子和在O/W子区域中是由于Na离子的影响.在双连续区(IZ)中SDS阴离子和Na阳离子都能影响导电行为增加表面活性剂含量有助于形成O/W微乳液,而助表面活性剂和油含量都增加有助于于形成W/O微乳液. 相似文献
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不同因素对高效氯氟氰菊酯微乳液相图的影响 总被引:5,自引:0,他引:5
通过电导率的测定研究了高效氯氟氰菊酯微乳液的结构及结构转变, 绘制了不同条件下高效氯氟氰菊酯微乳体系的拟三元相图, 讨论了十二烷基苯磺酸钠(SDBS)摩尔分数、电解质浓度、温度等因素对各类型微乳区形成的影响. 结果表明: ①随着SDBS摩尔分数增大, W/O型微乳区面积先减小后增大, BC和O/W型面积先增大后减小; ②随着电解质浓度增大, W/O、BC和O/W型微乳区面积均先增大后减小; ③随着温度升高, W/O型微乳区面积增大, BC和O/W型面积均减小. 相似文献
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Effect of the structures of microemulsions on chemical reactions 总被引:2,自引:0,他引:2
J. Hao 《Colloid and polymer science》2000,278(2):150-154
Two kinds of chemical reactions were studied in two different microemulsion systems: cetyltrimethylammonium bromide/1-butanol/10
and 25% n-octane/water and sodium dodecyl sulfonate/1-butanol/20% styrene/water. One reaction is a hydrolysis reaction, in which aspirin
and 2,4-dinitrochlorobenzene were used as the hydrolysis substrates. The second reaction is the polymerization of styrene,
which was initiated by using two initiators, water-soluble K2S2O8 and oil-soluble 2,2′-azobis(isobutyronitrile), and, at the same time, the polymerization of acrylamide, which was initiated
by NaHSO3, was also studied. All the hydrolysis reaction experimental results show that the hydrolysis is greatly affected by the structures
and the structural transitions of microemulsions. The hydrolysis rates are higher in water-in-oil (W/O) microemulsion media
and decrease with the addition of water. The rates increase in bicontinuous (BC) microemulsions and decrease in oil-in-water
(O/W) microemulsions. The transition points of the hydrolysis rates occurred at the two microemulsion structural transition
points from W/O to BC and from BC to O/W. The polymerization relationships between the conversions of styrene, the molecular
weights of polystyrene and the water contents of the microemulsion system were obtained. The effects of microemulsion structures
on the sizes of the polystyrene particles and on the molecular weights of the polymers are discussed. Polystyrene particles
with diameters of 10–60 nm were observed by microscopy. Our experimental polymerization results show that microemulsions are
suitable as media for the production of polymers, the molecular weights and the particle sizes of which can be controlled
and predicted by variations in microemulsion structures.
Received: 11 July 1999/Accepted: 26 July 1999 相似文献
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Microemulsion of Tween‐80/n‐butylalcohol/H2O system was prepared, and the microemulsion region as well as the influence of temperature and concentration of NaCl on the region were determined with ternary diagrams. The O/W, W/O, and B.C. regions were divided by the conductance method. The particle diameters of microemulsions with different NaCl concentrations or microemulsion‐enveloping all‐trans retinoic acid (ATRA) were measured with dynamic light scattering in O/W region. The release rate of ATRA was studied with dialysis a bag‐ultraviolet spectrophotometers and the anticancer activity of ATRA in microemulsion was investigated with cancer cells H446. Results showed that O/W microemulsion forms when water content is over 64% in the mixture. The influences of temperature and salinity on microemulsion region were very slight, and even the particle diameter decreased very little with increasing salt and ATRA concentrations. The microemulsion‐enveloping ATRA possessed eminent sustaining release efficiencys and the efficiency was further confirmed with the growth inhibitory effect test on human cancer cells H446. 相似文献
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This paper describes the use of water-in-oil (W/O) microemulsion eluents to achieve unique normal phase HPLC separations.
The effects of varying the oil type, co-surfactant, surfactant, use of mixed surfactant and water concentration upon the chromatographic
performance was assessed. Other parameters such as temperature and flow rate were also investigated. An optimised set of W/O
microemulsion HPLC (MELC) operating conditions was then applied to the separation of a range of acids, bases and neutral compounds.
The more water soluble compounds were more highly retained. W/O MELC was found to be especially suitable for determination
of water insoluble compounds. The drug content in bumetanide tablets was determined by W/O MELC with good linearity and accuracy.
The solubilising ability of the W/O microemulsion reduced sample preparation (precipitation and extraction) requirements compared
to conventional HPLC. The results obtained compared well with those obtained by a validated reverse phase HPLC method. It
is recommended that W/O MELC should be considered for routine applications, especially for the analysis of water insoluble
compounds in complex sample matrices. Further research is recommended to more definitely assess the operating parameters of
W/O MELC and to determine other applications. 相似文献
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QIANJun-hong GUORong ZHUJun 《高等学校化学研究》2004,20(6):785-789
The hydrolysis of cephanone in Triton X-100 micelle and Triton X-100/n-C5H11OH/H2O(O/W) microemulsion were studied by means of UV-Vis absorption spectroscopy. The results show that compared with water, Triton X-100 micelle and Triton X-100/n-C5H11OH/H2O (O/W) microemulsion can inhibit the hydrolysis of cephanone. The inhibition effects of Triton X-100 micelle and Triton X-100/n-C5H11OH/H2O (O/W) microemulsion on the hydrolysis of cephanone are related to the location of cephanone in the interphases of Triton X-100 miceUes and Triton X-100/n-C5H11OH/H2O(O/W) microemulsion droplets. 相似文献
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《Journal of Dispersion Science and Technology》2013,34(6):763-769
Abstract The hydrolysis of cephanone in water, cetyl trimethyl ammonium bromide (CTAB) micelle, and CTAB/n‐C5H11OH/H2O O/W microemulsion was studied through UV‐VIS absorption spectroscopy. The mechanism of the hydrolysis and the effects of both the acidity of the media and the composition of O/W microemulsion on the hydrolysis were studied. The results show that the hydrolysis rate of cephanone increases with the acidity. Compared with water, CTAB micelle and CTAB/n‐C5H11OH/H2O O/W microemulsion suppress this hydrolysis. The inhibition of the hydrolysis of cephanone by CTAB micelle and CTAB/n‐C5H11OH/H2O O/W microemulsion is related to the location of cephanone in the interphases of CTAB micelles and CTAB/n‐C5H11OH/H2O O/W microemulsion droplets. 相似文献
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Solè I Solans C Maestro A González C Gutiérrez JM 《Journal of colloid and interface science》2012,376(1):133-139
The influence of different dilution procedures on the properties of oil-in-water (O/W) nano-emulsions obtained by dilution of oil-in-water (O/W) and water-in-oil (W/O) microemulsions has been studied. The system water/SDS/cosurfactant/dodecane with either hexanol or pentanol as cosurfactant was chosen as model system. The dilution procedures consisted of adding water (or microemulsion) stepwise or at once over a microemulsion (or water). Starting emulsification from O/W microemulsions, nano-emulsions with droplet diameters of 20 nm are obtained, independently on the microemulsion composition and the dilution procedure used. In contrast, starting emulsification from W/O microemulsions, nano-emulsions are only obtained if the emulsification conditions allow reaching the equilibrium in an O/W microemulsion domain during the process. These conditions are achieved by stepwise addition of water over W/O microemulsions with O/S ratios at which a direct microemulsion domain is crossed during emulsification. The nature of the alcohol used as cosurfactant has been found to play a key role on the properties of the nano-emulsions obtained: nano-emulsions in the system using hexanol as cosurfactant are smaller in size, lower in polydispersity, and have a higher stability than those with pentanol. 相似文献
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微乳液增敏作用机理探讨:显色剂在微乳液中的分配系数 总被引:13,自引:0,他引:13
与胶束体系比较,显色剂PNA和CAS在油/水(O/W)微乳液中具有更大的分配系数,这表明O/W微乳液比胶束体系具有更好的增敏作用是因为O/W微乳液对显色剂PAN和CAS具有更好的增溶与富集作用所致。 相似文献
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Urea is found to show the hydrotrope action when the aqueous solubility of surfactant CTAB is enhanced while it will show the hydrotrope-solubilization action when the solubilized amount of n-C5H11OH in O/W microemulsion and that of water in W/O microemulsion are increased. The mechanism of the hydrotrope-sotubilization action of urea is in fact the increase of the stability of W/O and O/W microemulsion and structural transition from the lamellar liquid crystal phase to the bicontinuous structure. 相似文献