Theory of Charge Regulation of Colloidal Particles in Electrolyte Solutions

TL;DR

This paper introduces a comprehensive theory for calculating the effective surface charge and titration behavior of colloidal particles in electrolyte solutions, considering pH shifts and electrostatic effects, validated by reactive Monte Carlo simulations.

Contribution

The paper presents a novel, parameter-free theoretical framework for charge regulation in colloids that accurately matches simulation results.

Findings

Excellent agreement between theory and reactive Monte Carlo simulations.

The theory effectively predicts titration curves across various salt concentrations.

It accounts for pH shifts caused by electrolyte presence.

Abstract

We present a theory that enables us to calculate the effective surface charge of colloidal particles and to efficiently obtain titration curves for different salt concentrations. The theory accounts for the shift of pH of solution due to the presence of 1:1 electrolyte. It also accounts self-consistently for the electrostatic potential produced by the deprotonated surface groups. To examine the accuracy of the theory we have performed extensive reactive Monte Carlo simulations, which show excellent agreement between theory and simulations without any adjustable parameters.