Garti N, Clement V, Fanun M, Leser M E
Casali Institute of Applied Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel.
J Agric Food Chem. 2000 Sep;48(9):3945-56. doi: 10.1021/jf991393s.
This study explores some characteristics of microemulsions composed of sucrose monostearate (SMS), medium-chain triglycerides (MCT), or R-(+)-limonene, alcohols, and water. The systems are homogeneous, soft, and waxy solids at room temperature but liquefy and structure into homogeneous microemulsions when heated to >40 degrees C. The amount of solubilized water is enhanced as a function of the alcohol/oil ratio and is inversely proportional to the alcohol chain length. Over 60 wt % water can be solubilized in systems consisting of propanol/MCT/SMS at a weight ratio of 3:1:4 (initial weight ratio). These microemulsions are unique and differ from nonionic ethoxylated-based microemulsions in that their viscosity is very low and is reduced with increasing amounts of solubilized water. The electrical conductivity increases only slightly as a function of the water content and does not show typical bicontinuous or percolated behavior. The water in the core of the microemulsion strongly binds to the headgroups of the surfactant. Only at >15 wt % solubilization of water was free or bulk water detected in the core of the microemulsions. Such unique behavior of the core water might have a possible application in systems requiring monitoring of enzymatic (lipase) reactions carried out in the microemulsions as microreactors.
本研究探讨了由单硬脂酸蔗糖酯（SMS）、中链甘油三酯（MCT）或R-(+)-柠檬烯、醇类和水组成的微乳液的一些特性。这些体系在室温下为均匀、柔软的蜡状固体，但加热至>40℃时会液化并形成均匀的微乳液。增溶水的量随醇/油比的增加而增加，且与醇链长度成反比。在由丙醇/MCT/SMS组成的体系中，重量比为3:1:4（初始重量比）时，可增溶超过60 wt%的水。这些微乳液具有独特性，与基于非离子乙氧基化的微乳液不同，其粘度非常低，且随着增溶水量的增加而降低。电导率仅随含水量略有增加，未表现出典型的双连续或渗滤行为。微乳液核心中的水与表面活性剂的头基强烈结合。仅在水的增溶量>15 wt%时，才在微乳液核心中检测到游离或大量的水。微乳液核心水的这种独特行为可能在需要监测在微乳液作为微反应器中进行的酶促（脂肪酶）反应的体系中有潜在应用。
