Colloids electrophoresis for strong and weak ion diffusivity

TL;DR

This paper investigates how colloid charge and ion advection influence electrophoretic mobility, revealing a maximum mobility at high charge and significant heterogeneity at low salt concentrations.

Contribution

It introduces a mesoscopic modeling approach to study electrophoretic flow, highlighting the effects of charge and ion advection on colloid mobility.

Findings

Mobility increases with colloid charge, showing a maximum at high charge.

Ion advection enhances electrophoretic mobility, especially for highly charged colloids.

Heterogeneous electrophoretic response occurs at low salt concentrations due to overlapping ion layers.

Abstract

We study the electrophoretic flow of suspensions of charged colloids with a mesoscopic method that allows to model generic experimental conditions. We show that for highly charged colloids their electrophoretic mobility increases significantly and displays a mobility maximum on increasing the colloidal charge for all salt concentrations. The electrophoretic mobility of highly charged colloids is also enhanced significantly when ion advection is dominant, leading to a strong heterogeneity in the local electrophoretic response especially at low salt concentration, when ion diffuse layers overlap.