Anomalous microion distribution of concentrated electrolytes in the underscreening regime: Monte Carlo simulations

Abstract

The electrostatic screening phenomena on a macroion in 1:1 concentrated electrolytes are investigated in an underscreening regime. Using the primitive model, we obtained the density profile of microions near a macroion through Monte Carlo simulations. Beyond a critical electrolyte concentration, the density of both coions and counterions is at a maximum near a macroion. Consequently, the behaviour of microions in concentrated electrolyte solutions cannot be explained by the traditional picture of electric double layers. Additionally, we investigated the dependence of this phenomenon on the size of microions. These results shed light on the anomalous microion distribution of electrolytes due to the ion–ion correlations in the underscreening regime.

GRAPHICAL ABSTRACT

KEYWORDS:

• Electrolytes
• electric double layer
• Poisson–Boltzmann theory

Acknowledgments

The author acknowledges the Supercomputer Center, Institute of Solid State Physics at the University of Tokyo, for the use of their facilities.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by JSPS KAKENHI [grant number 16K05038].; Japan Society for the Promotion of Science