Nonlinear effects on electrokinetics of a highly charged porous sphere
Nonlinear effects on electrokinetics of a highly charged porous sphere
复制标题
高电荷多孔球体动电学的非线性效应
DOI：
10.1007/s00396-013-3130-7
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发表时间：
2014
影响因子：
2.4
通讯作者：
S. Bhattacharyya
中科院分区：
文献类型：
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作者：
Partha P. Gopmandal;S. Bhattacharyya
本研究的目的是为带电多孔粒子的电泳迁移率提供广泛的电动参数（例如粒子电荷密度、磁导率和德拜长度）的正确估计。基于能斯特-普朗克方程，考虑了离子传输的外部电场和流体对流，我们通过建立力平衡来估计粒子的迁移率。我们使用 Hermans 和 Fujita 的线性模型（K Nederl Akad Wet Proc Ser B 58:182–187, 1955）以及 Hsu 和 Lee 获得的基于 Poisson-Boltzmann 模型扰动的计算解（J Colloid Interface Sci 390:85–95, 2013）验证了我们的结果。对于薄双层的情况，即使粒子的电荷密度值较大，我们的计算结果也与线性模型一致。当考虑厚的德拜层时，线性模型高估了我们计算的迁移率解。然而，对于所有考虑的情况，都观察到当前模型与基于玻尔兹曼模型扰动的结果存在很大差异。我们通过抗衡离子的分布、净电荷密度和颗粒的有效电荷密度分析了双层极化和抗衡离子凝聚。
The motivation of the present study is to provide a correct estimate of the electrophoretic mobility of a charged porous particle for wide-range electrokinetic parameters, such as particle charge density, permeability, and Debye length. Based on the Nernst–Planck equation, which takes into account the external electric field and fluid convection on ion transport, we have estimated the mobility of the particle by establishing a force balance. We have validated our results with the linear model due to Hermans and Fujita (K Nederl Akad Wet Proc Ser B 58:182–187, 1955) and the computed solution based on perturbation of the Poisson–Boltzmann model as obtained by Hsu and Lee (J Colloid Interface Sci 390:85–95, 2013). For the case of thin double layer, our computed results agree with the linear model even for large values of charge density of the particle. The linear model overpredicts our computed solution for mobility when the thick Debye layer is considered. However, a large discrepancy of the present model from the results based on the perturbation of the Boltzmann model is observed for all the cases considered. We have analyzed the double-layer polarization and counterion condensation through the distribution of counterions, net charge density, and the effective charge density of the particle.