Triton X-100/n-C_4H_9OH/H_2O体系的扩散系数与结构特性

Diffusion Coefficient and Structure Properties of Triton X - 100/n - C_4H_9OH/H_2O System

在无外加探针条件下用循环伏安法测定了不同形状Triton X-100胶束的扩散系数,得到第一cmc(临界胶束浓度)为3.1×10^(-4)mol·L^(-1),第二cmc为1.3×10^(-3)mol·L^(-1),并给出了Triton X-100的电化学反应机理.随正丁醇含量的增加,Triton X-100球形胶束的扩散系数迅速增加,正丁醇的增溶分数略有降低,但胶束内微极性却降低较多;棒状胶束转变为球形胶束,正丁醇的增溶分数基本不变,但胶束内微极性降低.随温度升高,Triton X-100分子与胶束的扩散系数均增加.正丁醇含量<1.5％时,扩散活化能E_D随正丁醇含量增加而迅速增加;但正丁醇含量>1.5％时,E_D增加变缓.

The diffusion coefficient of Triton X - 100 of different shape is determined by cyclic voltammetry without any probe. The first one (3.1×10-4mol·L-1) and the second cmc (1.3×10-3 mol·L-1) are obtained. The mechanism of electrochemical reaction for Triton X - 100 is deduced by cyclic voltammetry, FT - IR spectrum, reaction at RRDE and pH measurement. When n - butanol is added, the diffusion coefficient of spherical micelles increases rapidly. The solubilization fraction of n -butanol decreases a little, but the micropolarity in spherical micelles decreases more. On the other hand, rodlike micelles change into spherical micelles, and the solubilization fraction of n - butanol is almost constant. The micropolarity in rodlike micelles, however, decreases when the n - butanol is added. Furthermore, the diffusion coefficient increases with temperature, and diffusion activation energy increases with n - butanol content.