On phase behavior and dynamical signatures of charged colloidal platelets

TL;DR

This study uses simulations and theoretical analysis to explore how electrostatic and geometric factors influence the phase behavior and dynamics of charged colloidal platelets, revealing new structures and slowed dynamics at higher densities.

Contribution

It introduces a detailed analysis of the electrostatic anisotropy effects on phase diagrams and predicts novel structures in charged colloidal platelet suspensions.

Findings

Electrostatic anisotropy explains complex phase features.

Identification of novel structures in phase diagram.

Evidence of slowed dynamics with increasing density.

Abstract

We investigate the competition between anisotropic excluded-volume and repulsive electrostatic interactions in suspensions of thin charged colloidal discs, by means of Monte-Carlo simulations and dynamical characterization of the structures found. We show that the original intrinsic anisotropy of the electrostatic potential between charged platelets, obtained within the non-linear Poisson-Boltzmann formalism, not only rationalizes the generic features of the complex phase diagram of charged colloidal platelets such as Gibbsite and Beidellite clays, but also predicts the existence of novel structures. In addition, we find evidences of a strong slowing down of the dynamics upon increasing density.