Effect of Size Polydispersity on Melting of Charged Colloidal Systems

TL;DR

This paper investigates how size polydispersity and macroion shielding influence the melting behavior of charged colloidal systems using molecular dynamics simulations and theoretical models.

Contribution

It introduces simple Yukawa potential prescriptions to model polydispersity and shielding effects, and analyzes their impact on phase boundaries.

Findings

Deviations in melting lines at small screening lengths.

Phase boundary deviations are sensitive to screening parameters.

Results align qualitatively with nonlinear Poisson-Boltzmann simulations.

Abstract

We introduce simple prescriptions of the Yukawa potential to describe the effect of size polydispersity and macroion shielding effect in charged colloidal systems. The solid-liquid phase boundaries were presented with the Lindemann criterion based on molecular dynamics simulations. Compared with the Robbins-Kremer-Grest simulation results, a deviation of melting line is observed at small $\lambda$, which means large macroion screening length. This deviation of phase boundary is qualitatively consistent with the simulation result of the nonlinear Poisson-Boltzmann equation with full many-body interactions. It is found that this deviation of the solid-liquid phase behaviour is sensitive to the screening parameter.