Particles inside Electrolytes with Ion-specific Interactions, Their Effective Charge Distributions and Effective Interactions

TL;DR

This paper investigates the statistical physics of colloidal particles in electrolytes with ion-specific interactions, deriving effective charge distributions and interactions for both weak and strong coupling regimes.

Contribution

It introduces a unified framework to analyze ion-specific effects on particle charge distributions and interactions in electrolytes, extending previous models to strong coupling cases.

Findings

Effective charge distribution depends on ion-specific interactions.

Far-field interactions are bilinear in effective charges.

Strong interactions require a unified treatment of ion-specific effects and correlations.

Abstract

In this work, we explore the statistical physics of colloidal particles that interact with electrolytes via ion-specific interactions. Firstly we study particles interact weakly with electrolyte using linear response theory. We find that the mean potential around a particle is linearly determined by the {\em effective charge distribution} of the particle, which depends both on the bare charge distribution and on ion-specific interactions. We also discuss the effective interaction between two such particles and show that, in far field regime, it is bilinear in the effective charge distributions of two particles. We subsequently generalize the above results to the more complicated case where particles interact strongly with the electrolyte. Our results indicate that in order to understand the statistical physics of non-dilute electrolytes, both ion-specific interactions and ionic correlations have to be addressed in a single unified and consistent framework.