Electroconvection near Two-Layer Composite Microparticles

Abstract

This paper presents the results of a numerical simulation of an electrolyte solution behavior near a spherical dielectric microparticle covered with a homogeneous ion-selective shell under the influence of an external electric field. The particle is assumed to be stationary, and the electrolyte either stays still or is pumped externally with a constant velocity in absence of the electric field. The field, in turn, generates electroosmotic flow near the particle’s surface. It is shown that concentration polarization can occur near the particle, whereas electrokinetic instability only occurs near particles with a sufficiently thick shell. When the particle’s surface charge is opposite to the one of its shell, non-stationary regimes may be observed when the shell is thin enough.