四乙基溴化铵对离子型表面活性剂胶束化行为的影响

用表面张力方法研究了有机电解质四乙基溴化铵（（Ｅｔ）４ＮＢ）对离子型表面活性剂ＳＤＳ和ＤＴＡＢ胶束化行为的影响，并与无机电解质ＮａＢｒ的结果比较．实验结果表明，（Ｅｔ）４ＮＢ促进ＳＤＳ胶束化的能力强于ＮａＢｒ；但促进ＤＴＡＢ胶束化的能力与ＮａＢｒ基本一样．这说明：（Ｅｔ）４Ｎ＋与ＳＤＳ胶束间除了相反电荷静电吸引外，其乙基和表面活性剂碳氢链间还具有弱疏水相互作用，两者结合使（Ｅｔ）４Ｎ＋嵌入ＳＤＳ胶束离子头基中；这种疏水作用强度不及静电力，在静电排斥下，（Ｅｔ）４Ｎ＋乙基和ＤＴＡ＋碳氢链间疏水相互作用未能发生．

Effect of Tetraethylammonium Bromide on the Micellization of Ionic Surfactants

The effects of tetraethylammonium bromide((Et) 4 NB) and NaBr on the micellization of ionic surfactants(sodium dodecyl sulfate, SDS; and dodecyl- trimethylammonium bromide, DTAB) have been investigated as a function of electrolyte concentration using surface tension measurements. The results showed that (Et) 4 NB is stronger to enhance the micellization of SDS than NaBr, but the effect of both (Et) 4 NB and NaBr is almost the same on improving the micellization of DTAB. The results were interpreted in terms of additional hydrophobic interaction between the ethyl groups of (Et) 4 N + ions and the alkyl tails of SDS besides the electrostatic attraction between them. Combination of both the interactions makes (Et) 4 N + s acting as spacers between the head-groups of SDS. However, the hydrophobic interaction is weaker than the electrostatic interaction, leading to that the former did not take place in the DTAB case because of the electrostatic repulsion between the positively charged head-group of DTAB and the (Et) 4 N + ions.