Electrophoresis of Two Spheres Along Their Line of Centers: Influence of Particle-Particle Interaction Forces

Electrophoresis of two spheres along their line of centers: influence of particle-particle interaction forces

 

Shiojenn Tseng,¹ Chih-Hua Huang,² Jyh-Ping Hsu^2,*

¹Department of Mathematics, Tamkang University, Tamsui, Taipei, Taiwan 25137

²Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan 10617 Tel: 886-2-23637448, Fax: 886-2-23623040, E-mail: jphsu@ntu.edu.tw

 

ABSTRACT

   Considering recent applications of electrophoresis conduced in nanoscaled devices, where particle-particle interaction can play a role, we studied for the first time the electrophoresis of two rigid spheres along their center line, taking account of the hydrodynamic, electric, and van der Waals interactions between them. Under the conditions of constant surface potential and surface charge density, the influences of the level of surface potential/charge density, the bulk salt concentration, and the particle-particle distance on their electrokinetic behaviors are examined. Numerical simulation reveals that these behaviors are much more complicated and interesting than those of isolated particles. In particular, we show that care must be taken in choosing an appropriate particle concentration in relevant experiment to avoid obtaining unreliable mobility data.

 

Keywords: electrophoresis; two spheres; electric double layer force; van der Waals force.

 

* Corresponding author e-mail: jphsu@ntu.edu.tw (J.-P. Hsu)