Electrostatic Disorder-Induced Interactions in Inhomogeneous Dielectrics

TL;DR

This paper studies how quenched surface charge disorder affects electrostatic interactions between charged surfaces with dielectric inhomogeneities and salt, revealing that image-charge effects can induce either attraction or repulsion.

Contribution

It introduces a theoretical framework for understanding disorder-induced interactions in inhomogeneous dielectrics within the weak-coupling regime.

Findings

Disorder-induced free energy depends on dielectric mismatch and charge distribution location.

Image-charge effects can cause both attractive and repulsive interactions.

The analysis applies within the linear weak-coupling regime, including mean-field and Gaussian fluctuations.

Abstract

We investigate the effect of quenched surface charge disorder on electrostatic interactions between two charged surfaces in the presence of dielectric inhomogeneities and added salt. We show that in the linear weak-coupling regime (i.e., by including mean-field and Gaussian-fluctuations contributions), the image-charge effects lead to a non-zero disorder-induced interaction free energy between two surfaces of equal mean charge that can be repulsive or attractive depending on the dielectric mismatch across the bounding surfaces and the exact location of the disordered charge distribution.