Remixing of a phase separated binary colloidal system with particles of different sizes in an external modulation

TL;DR

This study uses Monte Carlo simulations to investigate how external periodic modulation influences phase separation and mixing in a binary colloidal system with particles of different sizes, revealing a first-order phase transition.

Contribution

It demonstrates how external spatial modulation can control phase behavior and induce a first-order transition in a binary colloidal mixture, which was not previously characterized.

Findings

External modulation enhances mixing of particles.

Demixing shows a discontinuous order parameter change.

Specific heat peaks indicate a first-order phase transition.

Abstract

We explore phase behaviour of a binary colloidal system under external spatially periodic modulation. We perform Monte Carlo simulation on a binary mixture of big and small repulsive Lennard-Jones particles with diameter ratio 1:2. We characterise structure by isotropic and anisotropic pair correlation function, cluster size distribution, bond angle distribution, order parameter and specific heat. We observe demixing of the species in the absence of the external modulation. However, mixing of the species gets enhanced with increasing potential strength. The de-mixing order parameter shows discontinuity and the specific heat shows a peak with increasing modulation strength, characterizing a first order phase transition.