水/十二烷基硫酸钠/正丁醇/正辛烷系统的微乳液相行为和结构

Phase Behavior and Micro-Structure of Microemulsions of H_2O/C_(12)H_(25)SO_4 Na/n-C_4 H_9 OH/n-C_8 H_(18) System

用滴定法和色谱分析测定了H_2O/C_(12)H_(25)SO_4Na/n-C_4H_9OH/n-C_8H_(18)系统在表面活性剂十二烷基硫酸钠(SDS)与助表面活性剂正丁醇不同配比下的相图。微乳液只有在一定配比范围内方始形成,随着SDS配比增加,微乳区先逐步扩大。电导测定还可区别W/O型、双连续相和O/W型微乳液,并且双连续相区随SDS配比增加而扩大。但是当SDS配比很高时,由于溶解度减小和出现粘稠液晶相,微乳液区反而缩小。对分相区的系线测定还表明,富水相微乳液中SDS的含量恒高于富油相微乳液。

By using titration and chromatograph analysis, phase diagrams of H_2O/C_(12)H_(25)-SO_4Na/n-C_4H_9OH/n-C_8H_(18) system with various ratios of surfactant (SDS) to cosurfactant (n-C_4H_9OH) were measured. The diagrams indicated that microemulsions can only be formed in a certain range of combination of SDS and n-C_4H_9OH. The microemulsion domain first expands gradually as soonas the ratio of SDS increases. The W/O type microemulsion, bicontinuous region and the O/W microemulsion can be distinguished using the electric conductance determination. The bicontinuous domain also expands with the increase of SDS content. However, when the ratio of SDS continuously increases to a very large extent, the microemulsion domain ceases to expand. On the contrary, it gradually reduces due to the diminishing of solubilities of SDS and oil mixtures in water and to the appearance of viscous liquid crystal phase. The determination of tie lines further indicated that the SDS content in water-rich microemulsion phases is generally higher than that in the oil-rich phases.