Charge Renormalization, Effective Interactions, and Thermodynamics of Deionized Colloidal Suspensions

TL;DR

This paper presents a theory for charge renormalization in deionized colloidal suspensions, accurately predicting osmotic pressures by combining an effective model with a thermal criterion for counterion association.

Contribution

It introduces a new theoretical approach to determine effective macroion charges considering counterion association, aligning well with simulation results.

Findings

Predicted osmotic pressures match large-scale simulations.

Effective charges are significantly lower than bare charges in strong association cases.

The theory offers a computationally efficient way to analyze colloidal thermodynamics.

Abstract

Thermodynamic properties of charge-stabilised colloidal suspensions depend sensitively on the effective charge of the macroions, which can be substantially lower than the bare charge in the case of strong counterion-macroion association. A theory of charge renormalization is proposed, combining an effective one-component model of charged colloids with a thermal criterion for distinguishing between free and associated counterions. The theory predicts, with minimal computational effort, osmotic pressures of deionized suspensions of highly charged colloids in close agreement with large-scale simulations of the primitive model.