盐对阴阳离子表面活性剂水溶液相行为的影响

Influence of salts on behavior of cationic and anionic surfactant aqueous mixture

以阴阳离子表面活性剂混合体系为研究对象,通过测定体系在不同种类盐溶液中的三元相行为,探索了盐对体系相行为中的双水相区位置及相区宽度的影响规律.研究发现,阴离子双水相区的位置与宽度主要受盐阳离子的影响,盐阳离子半径越大,极化率越高,阴离子双水相区向阴离子表面活性剂方向移动的趋势越大,相区越宽;而盐的阴离子是影响阳离子双水相区位置与宽度的主要因素.

Aqueous two-phase system （ATPS） can be formed in the mixture of cationic and anionic surfactants solution. In the pseudo ternary phase diagram of SDS/CTAB/H2O/salt, there are two ATPS regions. The one, in which the content of anionic surfactant is more than cationic surfactant, is called ATPSa ; the other one, on the contrary, is called ATPSc. The position and width of ATPSa and ATPSc are influenced by salt, which is added in the system. The cation of salt mainly affect ATPSa. The larger the radius of salt cation, the nearer the ATPSa moves to the anionic surfactant, and the larger the ATPSa, width. The anion of salt is the main factor affecting ATPSc.