U型微乳水相增溶过程微观结构的模拟

利用耗散粒子动力学（DPD）方法对丁酸乙酯/无水乙醇/Tween80/水四组份微乳体系形成过程进行了模拟，其模拟内容包括水相增溶过程中微乳体系的微观结构和微乳液滴的形态特征变化、微乳体系内有效区域与无效区域的分界线等。模拟结果表明：水相增溶过程中，微乳体系能够在含水量为50%和70%时发生相的转变以及微乳液滴形态结构的变化：柱状→球状→柱状→球状。在油相与表面活性剂质量比小于等于5：5时，微乳体系水相可无限增溶；当油相与表面活性剂质量比为10：0，9：1，8：2，7：3，6：4时，微乳体系的最大增溶水量分别为25%，30%，35%，45%和50%，均为油包水型微乳，当水容量大于最大增溶水量时，微乳体系被破坏，分层。试验结果也发现：当含水量小于55%时，微乳体系电导率表明，微乳体系为油包水型；当含水量为55%-70%时，微乳体系为双连续型；当含水量大于70%时，微乳体系为水包油型。微乳体系的三相图也显示出微乳的有效区域。试验结果很好的吻合了模拟结果。

Mesoscopic simulation of microstructure changes in U-type microemulsion with water phase solubilizing

Dissipative particle dynamics(DPD)simulation method was used to study the ethyl butyrate/ethanol/Tween80(Polysorbate 80)/water four-component microemulsion system.The dynamical process of microemulsion system formation was investigated.The microstructure and droplet shape changed with water phase solubilizing was researched.The boundary of microemulsion effective region was also predicted.The results of DPD simulation were as follows:(1)With water phase solubilizing,the system microstructure would be transformed at a specific water content,i.e.,50% or 70% and meanwhile the shape of droplet transformed from columnar to spherical,then back to columnar and ultimately became spherical.(2)When oil-surfactant volume ratio was or less than 5∶5,water phase could be infinitely diluted;when oil-surfactant volume ratio was 10∶0,9∶1,8∶2,7∶3 and 6∶4,the maximum water content of microemulsion system was respectively 25%,30%,35%,45% and 50%,and microemulsion was water-in-oil.When the water content of microemulsion was over the maximum water content,it would be destroyed and became layered.Experiments showed that(1)According to the changes of microemulsion system conductivity,the microemulsion was water-in-oil when water content was less than 55%;the microemulsion was bi-continuous when water content was between 55% and 70%;the microemulsion was oil-in-water when water content was more than 70%.(2)The pseudo-ternary phase diagrams of system presented an effective region of microemulsion.The results of DPD simulation coincided with the experiment results.