聚氧乙烯与非等摩尔正负离子表面活性剂混合体系的相互作用

Interaction of Polyethylene Oxide with Non-equimolarly Mixed Cationic-Anionic Surfactants

通过黏度、动态光散射和透射电镜方法研究了聚氧乙烯(PEO)对正负离子混合表面活性剂癸基磺酸钠(C10SO3)-癸基三乙基溴化铵(C10NE)聚集体的影响.实验结果表明,加入PEO后,非等摩尔C10SO3-C10NE混合物的聚集体大小没有明显改变,只有等摩尔混合物的聚集体发生了明显的长大,且仍为囊泡,说明PEO只对囊泡体系有显著的影响,对胶团体系则没有明显的影响.在接近等摩尔混合时,混合体系中C10SO3与C10NE过量程度相同的情况下,PEO对C10NE过量的体系影响更大.PEO对囊泡体系的影响主要表现为PEO通过对囊泡的"空缺絮凝"作用(Depletion interaction)使囊泡长大,而对于非等摩尔混合的胶团溶液,由于胶团之间存在较强的静电排斥作用而无法发生聚集.PEO对C10NE过量的体系影响更大,主要是由于C10NE过量体系中的聚集体比C10SO3过量体系中的更接近于等摩尔组成.

The interactions of polyethylene oxide（PEO） with the mixtures of sodium decylsulfonate（C10SO3 ） and decyhriethylammonium bromide （C10NE） were investigated by viscosity, dynamic light scattering and transmission electron microscopy techniques. It showed that PEO had no significant effects on the aggregate size of the non-equimolarly mixed cationic-anionic surfactants. Striking growth of the aggregates was observed only when the molar ratio of CloNE to C10SO3 closed to equimolar, and those strikingly grown aggregates were still vesicles. Therefore, it can be concluded that PEO has striking effects only on vesicle-involved systems, whereas no significant effect on micellar systems. Around equimolar mixing ratio, PEO exhibited stronger influence on C10 NE-excessed systems than on C10SO3-excessed ones when the excess extents of C10SO3 and C10NE are the same. The growth of vesicles induced by PEO could be explained in terms of depletion interaction between PEO and vesicles. The fact that PEO has no significant effect on non-equimolarly mixed micellar systems could be ascribed to the strong electrostatic repulsion between charged micelles. The stronger influence of PEO on C10NE-excessed systems was ascribed to that the aggregates in CloNE-excessed systems were closer to equimolar composition than those in C10SO3-excessed ones.