Electrophoresis of Conducting and Non-Conducting Microparticles in a Polar Electrolyte Under a Strong Electric Field

This work focuses on the study of electrophoresis of conducting and non-conducting particles in a polar electrolyte solution under a strong electric field. Numerical modeling results are presented for both types of particles, including distributions of cation and anion concentrations, charge density, total ion concentration, and ion fluxes near the particle surface. It is shown that, for a dielectric surface with a sufficiently high surface charge, an extended space-charge region can form. The emergence of this region is driven by high surface conductivity in the electric double layer and by intense tangential ion fluxes. Qualitative differences in the mechanism of extended space charge formation are revealed when comparing ion-selective and dielectric particles. The findings enhance our understanding of nonlinear electrokinetic processes and can be useful in designing microfluidic systems and colloidal technologies.