正负离子混合表面活性剂的双水相系统

Aqueous Two-phase System of Cationic-anionic Mixed Surfactants

实验测定并绘制了正离子型表面活性剂十二烷基硫酸钠 ( SDS)和负离子型表面活性剂十六烷基三甲基溴化铵 ( CTAB)混合表面活性剂水溶液的双水相相图。考察了温度和外加盐溴化钠对双水相区域的影响 ,并用电镜观察了双水相的微观结构。结果表明 ,该系统可以在 SDS或CTAB过量的两个区域形成双水相 ,属于最低临界共溶温度 ( LCST)类型 ,温度升高导致双水相区域扩大。溴化钠的加入使双水相区域扩大并向混合比增大的方向移动。加入溴化钠后 ,对 CTAB过量区双水相的平衡有明显的促进作用 。

The phase diagrams of anionic surfactant sodium dodecyl sulfonate (SDS) and cationic surfactant cetyl trimethyl amine bromide (CTAB) aqueous mixtures at different temperatures have been measured. The influence of added salt sodium bromide (NaBr) on the aqueous two phase (ATP) regions has been observed. The microstructures of each ATP were observed by TEM. It is shown that there are two lower critical solution temperature (LCST) ATP systems in two regions in which SDS or CTAB is excessive. The ATP regions were enlarged with the increasing temperature. The ATP regions can also be enlarged by adding NaBr and moving to larger mixing ratio of anionic and cationic surfactants. The rate of phase separation can be greatly speeded up by adding NaBr to ATP regions in which CTAB is excessive. However, little effect was observed for ATP regions in which SDS is excessive.