Aggregation kinetics in a model colloidal suspension

TL;DR

This study uses molecular dynamics simulations to explore how colloidal particles aggregate, revealing that simple repulsive interactions can lead to stable cluster phases resembling equilibrium fluctuations.

Contribution

It demonstrates that short-range repulsive forces alone can produce cluster phases in colloids, providing insight into their formation mechanisms.

Findings

Clusters form via coagulation-fragmentation dynamics.

Clusters exhibit exponential size distribution.

Repulsive interactions can induce equilibrium cluster phases.

Abstract

We present molecular dynamics simulations of aggregation kinetics in a colloidal suspension modeled as a highly asymmetric binary mixture. Starting from a configuration with largely uncorrelated colloidal particles the system relaxes by coagulation-fragmentation dynamics to a structured state of low-dimensionality clusters with an exponential size distribution. The results show that short-range repulsive interactions alone can give rise to so-called cluster phases. For the present model and probably other, more common colloids, the observed clusters appear to be equilibrium phase fluctuations induced by the entropic inter-colloidal attractions.