Peltonen LJ, Yliruusi J
Department of Pharmacy, Pharmaceutical Technology Division, University of Helsinki, Helsinki, FIN-00014, Finland
J Colloid Interface Sci. 2000 Jul 1;227(1):1-6. doi: 10.1006/jcis.2000.6810.
The purpose of this study was to investigate the interfacial properties of sorbitan monoesters (Span 20, 40, 60, and 80). The surface pressure was investigated at the water-air interface using a Langmuir-Blodgett apparatus. Interfacial tensions at n-hexane-air and water-n-hexane interfaces were measured by a du Nouy tensiometer. The effects of different surface-active agents and their concentrations on the interfacial properties of surfactant films were determined. With saturated sorbitan monoesters the lengthening of the hydrocarbon chain increases the collapse pressure and molecular area at the water-air interface. Unsaturated Span 80 had a lower collapse pressure and a larger molecular area than its saturated counterpart Span 60. Under compression-expansion cycles, all sorbitan monoesters showed hysteresis effects. At the n-hexane-air interface there were no differences in the interfacial tension between different sorbitan monoesters. At the water-n-hexane interface, differences in CMCs were small, but the surface excess of Span 80 was markedly smaller and the molecular area larger than the corresponding values of other sorbitan monoesters. Copyright 2000 Academic Press.
本研究的目的是研究脱水山梨醇单酯（司盘20、40、60和80）的界面性质。使用朗缪尔-布洛杰特仪器在水-空气界面研究表面压力。用杜诺伊张力计测量正己烷-空气界面和水-正己烷界面的界面张力。确定了不同表面活性剂及其浓度对表面活性剂膜界面性质的影响。对于饱和脱水山梨醇单酯，烃链的延长会增加水-空气界面处的崩溃压力和分子面积。不饱和司盘80比其饱和对应物司盘60具有更低的崩溃压力和更大的分子面积。在压缩-膨胀循环下，所有脱水山梨醇单酯均表现出滞后效应。在正己烷-空气界面，不同脱水山梨醇单酯之间的界面张力没有差异。在水-正己烷界面，临界胶束浓度的差异很小，但司盘80的表面过剩明显较小，分子面积大于其他脱水山梨醇单酯的相应值。版权所有2000年学术出版社。
