Curvature Elasticity of the Electric Double Layer

TL;DR

This paper derives formulas for the bending properties of an electric double layer using mean-field electrostatics, applicable to various electrolyte models, to understand their elastic behavior.

Contribution

It introduces a general framework for calculating the curvature elasticity of electric double layers based on electrolyte equations of state.

Findings

Derived expressions for bending stiffness, Gaussian modulus, and spontaneous curvature.

Applied the framework to lattice-gas Poisson-Fermi and Poisson-Carnahan-Starling models.

Provided insights into the elastic properties of electric double layers in different electrolyte models.

Abstract

Mean-field electrostatics is used to calculate the bending moduli of an electric double layer for fixed surface charge density of a macroion in a symmetric 1:1 electrolyte. The resulting expressions for bending stiffness, Gaussian modulus, and spontaneous curvature refer to a general underlying equation of state of the electrolyte, subject to a local density approximation and the absence of dipole and higher-order fields. We present results for selected applications: the lattice-gas Poisson-Fermi model with and without asymmetric ion sizes, and the Poisson-Carnahan-Starling model.