Clustering, conductor-insulator transition and phase separation of an ultrasoft model of electrolytes

TL;DR

This study explores how ultrasoft oppositely charged macroions cluster and undergo phase separation, revealing a conductor-insulator transition driven by ion pairing and suggesting a tricritical point in the phase diagram.

Contribution

It provides new insights into the phase behavior and conductor-insulator transition of ultrasoft electrolyte models using combined simulation techniques.

Findings

Ion pairing induces a sharp conductor-insulator transition.

Phase separation occurs below a critical temperature.

Preliminary evidence suggests a tricritical point.

Abstract

We investigate the clustering and phase separation of a model of ultrasoft, oppositely charged macroions by a combination of Monte Carlo and Molecular Dynamics simulations. Static and dynamic diagnostics, including the dielectric permittivity and the electric conductivity of the model, show that ion pairing induces a sharp conductor-insulator transition at low temperatures and densities, which impacts the separation into dilute and concentrated phases below a critical temperature. Preliminary evidence is presented for a possible tricritical nature of the phase diagram of the model.