C12-s-C12•2Br在正庚烷中反胶团形成及增溶水特性

在助表面活性剂正己醇存在下, 季铵盐Gemini表面活性剂C12-s-C12?2Br(s=2、3、4、5、6、8、12)在正庚烷中形成了反胶团. 以水增溶法测定了临界反胶团浓度cmcw, 这些cmcw均分别小于它们在水中生成正胶团的临界浓度cmcaq. cmcw随s的变化规律与cmcaq随s的变化规律类似, 在s=4时出现极大值. 由水增溶法和电导法获得的反胶团饱和增溶水量(mw或mc)约在s=5时出现最大值. 这些现象被归结为联接链构型的变化.

Reverse Micelle Formation of C12-s-C12· 2Br in n-heptane and Their Solubilization for Water

The critical reverse micelle concentrations of quaternary ammonium Gemini surfactants C12-s-C12?2Br (s=2, 3, 4, 5, 6, 8, 12) in n-heptane (cmcw) have been determined by water solubilization method. These values are smaller than the critical micelle concentration (cmcaq) of them in aqueous solution, where C12-s-C12?2Br forms normal micelles. The cmcw as a function of s goes through a maximum at s=4, which is similar to the variation regularity of cmcaq with s. The saturation amounts of water solubilized in the reverse micelles measured by both water solubilization method and conductivity method show a maximum at about s=5. This is attributed to the change of folded conformation of the spacer chain.