DTAB在乙二醇/水混合溶剂中的聚集研究

通过电导、粘度、密度的测量研究了阳离子表面活性剂十二烷基三甲基溴化铵（DTAB）在乙二醇（EG）／水混合溶剂中的胶束性质．根据测量数据，求得了溶剂中乙二醇的质量分数分别为0，20％，40％，60％及80％时，DTAB的临界胶束浓度（cmc）、反离子的有效解离度、胶束形成的自由能变化、表观摩尔体积改变量、特性粘度等物化参数．实验发现，随着混合溶剂中乙二醇含量的增加，DTAB的cmc值增大，胶束形成的自发性越来越低，形成的胶束内部空间变小．尤其是当混合溶剂中乙二醇的质量分数在40％及以上时，DTAB的表观摩尔体积改变量变为负数．讨论了乙二醇的加入影响DTAB胶束形成的原因．

Study on the aggregation of dodecyltrimethylammonium bromide in a binary mixture of ethylene glycol and water

Micellar properties of dodecyltrimethylammonium bromide(DTAB) in an aqueous mixture of ethylene glycol(EG) were investigated by conductivity,viscosity and density measurements.The critical micelle concentration(CMC),the effective degree of dissociation of counter-ions,the change of free energy and the apparent molar volume,and the intrinsic viscosity in the micellization were calculated when the mass fraction of EG in the mixture was 0,20%, 40%,60% and 80%,respectively.With the content of EG increasing,the micellization became less spontaneous,the value of CMC increased and the void space of the micelles decreased.Especially when the content of EG was above 40%,the change of the apparent molar volume was negative.The effect on the DTAB micellization by adding EG was discussed.