Yang Likun, Zhao Kongshuang
College of Chemistry, Beijing Normal University, Beijing 100875, China.
Langmuir. 2007 Aug 14;23(17):8732-9. doi: 10.1021/la700665s. Epub 2007 Jul 17.
Dielectric relaxation spectra of CTAB reverse micellar solutions, CTAB/isooctane/n-hexanol/water systems with different concentrations of CTAB and different water contents, were investigated in the frequency range from 40 Hz to 110 MHz. Two striking dielectric relaxations were observed at about 10(4) Hz and 10(5) Hz, respectively. Dielectric parameters were obtained by fitting the data using the Cole-Cole equation with two Cole-Cole dispersion terms and the electrode polarization term. These parameters show different variation with the increase of the concentration of CTAB or the water content. In order to explain the two relaxations systematically and obtain detailed information on the systems and the inner surface of the reverse micelles, an electrical model has been constituted. On the basis of this model, the low-frequency dielectric relaxation was interpreted by the radial diffusion of free counterions in the diffuse layer with Grosse model. For the high-frequency dielectric relaxation, Hanai theory and the corresponding analysis method were used to calculate the phase parameters of the constituent phases in these systems. The reasonable analysis results suggest that the high-frequency relaxation probably originated from the interfacial polarization. The structural and electrical information of the present systems were obtained from the phase parameters simultaneously.
研究了不同CTAB浓度和不同含水量的CTAB反胶束溶液（CTAB/异辛烷/正己醇/水体系）在40Hz至110MHz频率范围内的介电弛豫谱。分别在约10⁴Hz和10⁵Hz处观察到两个明显的介电弛豫。通过使用具有两个Cole-Cole色散项和电极极化项的Cole-Cole方程对数据进行拟合获得介电参数。这些参数随CTAB浓度或含水量的增加呈现出不同的变化。为了系统地解释这两种弛豫并获得有关该体系和反胶束内表面的详细信息，构建了一个电学模型。基于该模型，用Grosse模型通过扩散层中自由抗衡离子的径向扩散来解释低频介电弛豫。对于高频介电弛豫，使用Hanai理论和相应的分析方法来计算这些体系中各组成相的相参数。合理的分析结果表明高频弛豫可能源于界面极化。同时从相参数中获得了本体系的结构和电学信息。
