Critical Micellar Concentrations of Quaternary Ammonium Surfactants with Hydroxyethyl Substituents on Headgroups Determined by Isothermal Titration Calorimetry
作者:Wei Tong、Qing Zheng、Shuang Shao、Qunfang Lei、Wenjun Fang
DOI:10.1021/je100288k
日期:2010.9.9
micelle formations in aqueous solutions of a set of quaternary ammonium surfactants, N-alkyl-N-2-hydroxyethyl-N,N-dimethyl ammonium bromide (CnHDAB, n = 12, 14, and 16), N-alkyl-N,N-2-dihydroxyethyl-N-methyl ammonium bromide (CnDHAB, n = 12, 14, and 16), along with N-dodecyl-N,N,N-trimethyl ammonium bromide (DTAB), and N-cetyl-N,N,N-trimethyl ammonium bromide (CTAB), were investigated by the isothermal
一组季铵表面活性剂,N-烷基-N -2-羟乙基-N,N-二甲基溴化铵(C n HDAB,n = 12、14和16),N-烷基- ñ,ñ -2- dihydroxyethyl- ñ甲基溴化铵(C ñ DHAB,ñ = 12,14,和16),具有沿ñ -dodecyl- ñ,ñ,ñ -三甲基铵溴化物(DTAB)和ñ -十六烷基-N,N,N用等温滴定热法(ITC)研究了溴化三甲基溴化铵(CTAB)。确定了在六个不同温度下的临界胶束浓度(CMCs)和胶束化焓。然后使用伪相分离模型计算胶束化的熵和吉布斯自由能。讨论了温度,链烷烃链的长度以及表面活性剂头基上羟乙基取代基数量对热力学数据的影响。每种表面活性剂的CMC值随温度的升高而略有增加。在给定温度下,烷烃链长度的增加和羟乙基取代基的数目均导致CMC值的降低。