液--液界面双电层统计力学处理

Statistical Mechanical Treatment For the Electrical Double Layer at Ities: Analysis of MVN Model

应用巨正则系综统计法处理液／液界面（ＩＴＩＥＳ）双电层体系。根据ＭＶＮ模型，假定溶液中离子可穿入界面内层（定向溶剂分子层），由体系（内层）巨正则配分函数导出内层微分电容（Ｃ１）统计表达式，拟合计算Ｃ１随该层表面电荷密度（σｍ）变化关系。理论同时表明。

A statistical mechanical treatment for electrical double layer at the interface between two immiscible elecrolyte solution (ITIES) is presented by using grand canonical method based on the MVN model. For the MVN model, the ITIES was represented by that the two space charge regions are separated by an inner layer of the oriented solvent molecules. Assuming that the ions were allowed to penetrated into the solvent compact layer over some distance, then the grand canonical partition function of the inner layer at ITIES can be given. While the mean field approximation is employed to estimate the interactive potential energy of the system, including the dipole dipole, dipole ion and ion ion interaction. A relationship between the differential capacity and the surface charge fluctuation is shown, and the statistical expression of inner layer differential capacity (C 1) is derived. A fitting curve of the C 1 as a function of surface charge density ( σ m ) at water/nitrobenzene interface is given, which is agreed with the generally theoretical inferences.