Long-range electrostatic interactions between like-charged colloids: steric and confinement effects

TL;DR

This paper analytically demonstrates that like-charged colloids in confined electrolytes experience repulsive interactions when considering steric effects and finite ion sizes, extending classical theories to more realistic conditions.

Contribution

It introduces a Modified Poisson-Boltzmann theory that accounts for ion size and confinement, providing new analytical insights into colloidal interactions.

Findings

Interactions are repulsive under confinement with steric effects.

Finite ion size influences the strength of colloidal repulsion.

Extends classical Poisson-Boltzmann results to more realistic scenarios.

Abstract

Within the framework of a Modified Poisson-Boltzmann theory accounting for steric effects of microions, we prove analytically that the effective pair interactions between like-charge colloids immersed in a confined electrolyte are repulsive. Our approach encompasses and extends previously known results to the case of complete confinement, and further incorporates the finite size of the microions which is absent in the standard Poisson-Boltzmann theory.