阳离子表面活性剂R_(16)HTAB及其复配体系的流变性能

Rheological properties of cationic surfactant R_(16)HTAB and its mixed systems

用稳态和动态流变学方法研究了3-十六烷氧基-2-羟丙基三甲基溴化铵(R16HTAB)单纯以及水杨酸钠(NaSal)存在下溶液的流变特性.无盐体系中,在测定的浓度范围内,表面活性剂与零剪切黏度呈指数关系(0∝c2.53).水杨酸钠的加入促进了体系由球状向蠕虫状胶束转化.Cox-Merz规则和Cole-Cole图证明,混合体系生成了蠕虫状胶束.与传统的CTAB比较,无论水杨酸钠存在与否,R16HTAB水溶液的流变性能均较好,这主要归因于羟丙基基团的插入,使得R16HTAB和NaSal分子之间形成氢键连接,生成了更加稳定的三维网络结构.应用冷冻蚀刻电子显微镜技术进一步证实了体系中蠕虫状胶束的存在.

The rheological properties of cationic surfactant 3-hexadecyloxy-2-hydroxypropyl trimethyl ammonium bromide （R16HTAB） aqueous solution and mixed system with sodium salicylate （NaSal） were studied using steady state and frequency sweep rheological measurements. In the absence of a salt, the η0 and R16HTAB concentrations give relationship of the power law, i.e. η0∝^2.53 in the examined concentration range. The addition of NaSal promoted the micellar growth yielding wormlike micelles in the systems and resulted in generating the wormlike micelles. Cox-Merz rule and Cole-Cole plot proved that the R16HTAB/NaSal mixed system have transformed into wormlike micelle. By comparison, the rheological properties of R16HTAB aqueous solution are better than that of the traditional CTAB whether there is salt or not. This mainly attributed to the insertion of a 2-hydroxypropoxy group between the head-group and the alkyl chain of quaternary ammonium salts, resulting in the strong junction between the R16HTAB and the salicylate counter ion, and the very stable three-dimensional network structure. FF-TEM technique was used to confirm the presence of the wormlike micelle.