Johnson TJ, Davis EJ
Department of Chemical Engineering, University of Washington, Seattle, Washington, 98195-1750
J Colloid Interface Sci. 1999 Jul 15;215(2):397-408. doi: 10.1006/jcis.1999.6282.
An analysis of the electrophoretic motion of charged colloidal particles in a concentrated suspension is developed to predict the electrophoretic mobility of the particles and the electrical conductivity of the suspension. The analysis is based on a unit cell model that takes into account particle-particle hydrodynamic interactions and includes relatively thick electric double layers. The fluid motion in the unit cell is treated by writing the relevant Navier-Stokes equation in terms of the stream function and vorticity. The governing equations were then solved by a finite-difference method. The calculated electrophoretic mobilities are in agreement with prior analytical solutions for moderately concentrated suspensions, and the theory reduces to the result of O'Brien and White for low to moderate zeta potentials and dilute suspensions and to the classical result of Smoluchowski for thin double layers and dilute suspensions. A parametric study shows that the electrical conductivity of the suspension relative to a free electrolyte solution is affected by the counterion to co-ion diffusivity ratio, the double-layer thickness, and the volume fraction of particles. For a dispersion of moderately charged particles (moderate zeta potentials) with thick double layers, the numerical model predicts the electrical conductivity in agreement with experimental values reported in the literature. Copyright 1999 Academic Press.
开展了对浓悬浮液中带电胶体颗粒电泳运动的分析，以预测颗粒的电泳迁移率和悬浮液的电导率。该分析基于一个单胞模型，该模型考虑了颗粒间的流体动力学相互作用，并包含相对较厚的电双层。通过用流函数和涡度表示相关的纳维-斯托克斯方程来处理单胞中的流体运动。然后用有限差分法求解控制方程。计算得到的电泳迁移率与中等浓度悬浮液的先前解析解一致，并且该理论在低至中等zeta电位和稀悬浮液时简化为奥布赖恩和怀特的结果，在薄双层和稀悬浮液时简化为斯莫卢霍夫斯基的经典结果。参数研究表明，悬浮液相对于自由电解质溶液的电导率受反离子与共离子扩散率比、双层厚度和颗粒体积分数的影响。对于具有厚双层的中等带电颗粒（中等zeta电位）的分散体系，数值模型预测的电导率与文献报道的实验值一致。版权所有1999年学术出版社。
