On the regimes of charge reversal

TL;DR

This paper investigates charge reversal in the electrical double layer using integral equations, identifying two regimes—oscillatory and non-oscillatory—and providing a simple formula to distinguish them, with validation against simulations.

Contribution

It introduces a simple formula to differentiate charge reversal regimes and reveals a symmetry between electrostatic and size correlations, supported by numerical analysis.

Findings

Two regimes of charge reversal identified: oscillatory and non-oscillatory.

A simple formula distinguishes the two regimes.

Results agree with other theories and molecular simulations.

Abstract

Charge reversal of the planar electrical double layer is studied by means of a well known integral equations theory. By a numerical analysis, a diagram is constructed with the onset points of charge reversal in the space of the fundamental variables of the system. Within this diagram two regimes of charge reversal are identified, referred to as oscillatory and non oscillatory. We found that these two regimes can be distinguished through a simple formula. Furthermore, a symmetry between electrostatic and size correlations in charge reversal is exhibited. The agreement of our results with other theories and molecular simulations data is discussed.