Arrested phase separation in a short-ranged attractive colloidal system: A numerical study

TL;DR

This numerical study explores how short-ranged attractive colloids undergo arrested phase separation, forming glasses that retain memory of their phase separation history, with results independent of microscopic dynamics.

Contribution

It demonstrates the competition between phase separation and dynamical arrest in colloids, revealing how arrested structures depend on temperature and packing fraction.

Findings

At low temperature, phase separation is interrupted by attractive glass formation.

At higher temperature, phase separation proceeds without arrest.

The final arrested structure retains a frozen spinodal decomposition signature.

Abstract

We numerically investigate the competition between phase separation and dynamical arrest in a colloidal system interacting via a short ranged attractive potential. Equilibrium fluid configurations are quenched at two different temperatures below the critical temperature and followed during their time evolution. At the lowest studied $T$, the phase separation process is interrupted by the formation of an attractive glass in the dense phase. At the higher $T$, no arrest is observed and the phase separation process proceeds endless in the simulated time window. The final structure of the glass retains memory of the interrupted phase separation process in the form of a frozen spinodal decomposition peak, whose location and amplitude is controlled by the average packing fraction. We also discuss the time evolution of the non ergodicity parameter, providing evidence of a progressively decreasing localization length on increasing the packing fraction. Finally, we confirm that the reported results are independent on the microscopic dynamics.