Electrolytes between dielectric charged surfaces: Simulations and theory

TL;DR

This paper introduces a fast simulation method and a mean-field theory to study electrolyte solutions confined between dielectric charged surfaces, with validated results and exploration of charge asymmetry effects.

Contribution

It presents a novel simulation technique using modified 3D Ewald summation and develops a mean-field theory for ionic distributions in dielectric slab geometries.

Findings

Good agreement between simulation and theory validates both methods.

Ionic density profiles are characterized in different electrostatic coupling regimes.

Charge asymmetry effects are explored in neutral confinement scenarios.

Abstract

We present a simulation method to study electrolyte solutions in a dielectric slab geometry using a modified 3D Ewald summation. The method is fast and easy to implement, allowing us to rapidly resum an infinite series of image charges. In the weak coupling limit, we also develop a mean-field theory which allows us to predict the ionic distribution between the dielectric charged plates. The agreement between both approaches, theoretical and simulational, is very good, validating both methods. Examples of ionic density profiles in the strong electrostatic coupling limit are also presented. Finally, we explore the confinement of charge asymmetric electrolytes between neutral surfaces.