College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, China.
J Phys Chem B. 2012 May 3;116(17):5213-25. doi: 10.1021/jp300568k. Epub 2012 Apr 24.
The first and the second critical micelle concentration (CMC(1) and CMC(2)) for three alkyltrimethylammonium bromide (C(n)TAB)/sodium dodecylsulfonate (AS)/H(2)O mixed systems, and CMC(1) for trimethylene-1,3-bis(dodecyldimethylammonium bromide) (12-3-12)/AS/H(2)O mixed system have been measured. The largest negative β(m) value means the strongest synergism between 12-3-12 and AS. The CMC(1) and CMC(2) for the C(n)TAB/AS/H(2)O mixed systems decrease with the increase of n. The equimolar mixed systems give the smallest CMC(1) values, whereas the CMC(2) values decrease with the increase of the composition of the surfactant with higher surface activity in the C(n)TAB/AS/H(2)O mixed systems. For the C(16)TAB/AS mixed systems far from equimolar, specific counterion effect on lowering CMC(1) enhances according to the Hofmeister series. There is slightly or no salt effect on the CMC(1) of the other wide composition range of C(16)TAB/AS/H(2)O mixed system. The pseudophase separation model coupled with the dissociated Margules model has been proposed and gives satisfactory description of the mixed CMC(1), the calculated micellar compositions are in well accordance with composition information from the ζ potential measurements. The addition of salt into the C(16)TAB/AS/H(2)O mixed system, leads to a certain degree of decrease in CMC(2). In addition to counterion effect, the co-ion effect on CMC(2) of the mixed system was explained using Collins' concept of matching water affinities.
已测量三种烷基三甲基溴化铵（C(n)TAB）/十二烷基硫酸钠（AS）/H₂O 混合体系的第一和第二临界胶束浓度（CMC(1)和 CMC(2)），以及三亚甲基-1,3-双（十二烷基二甲基溴化铵）（12-3-12）/AS/H₂O 混合体系的 CMC(1)。β(m)值最大表示 12-3-12 和 AS 之间的协同作用最强。C(n)TAB/AS/H₂O 混合体系的 CMC(1)和 CMC(2)随 n 的增加而降低。等摩尔混合体系给出最小的 CMC(1)值，而 CMC(2)值随表面活性较高的表面活性剂在 C(n)TAB/AS/H₂O 混合体系中的组成增加而降低。对于远离等摩尔的 C(16)TAB/AS 混合体系，根据 Hofmeister 序列，特定抗衡离子降低 CMC(1)的效应增强。在其他宽组成范围的 C(16)TAB/AS/H₂O 混合体系中，盐对 CMC(1)的盐效应较小或没有。已提出假相分离模型与解离 Margules 模型相结合，对混合 CMC(1)进行了令人满意的描述，计算得到的胶束组成与 ζ 电位测量得到的组成信息非常吻合。向 C(16)TAB/AS/H₂O 混合体系中添加盐会导致 CMC(2)一定程度的降低。除了抗衡离子效应外，还使用 Collins 的水亲和力匹配概念解释了混合体系中 CMC(2)的同离子效应。
