Reversible gelation and dynamical arrest of dipolar colloids

TL;DR

This study uses molecular dynamics simulations to demonstrate that dipolar colloids can form reversible gels through self-assembly and kinetic arrest, revealing insights into gelation and dynamical arrest mechanisms.

Contribution

It introduces a simple model showing reversible gelation and dynamical arrest in dipolar colloids, highlighting the transition from transient networks to frozen gels.

Findings

Formation of reversible gels at low volume fractions

Transition from percolating network to arrested state upon cooling

Dynamical signatures similar to jamming in dense dispersions

Abstract

We use molecular dynamics simulations of a simple model to show that dispersions of slightly elongated colloidal particles with long-range dipolar interactions, like ferrofluids, can form a physical (reversible) gel at low volume fractions. On cooling, the particles first self-assemble into a transient percolating network of cross-linked chains, which, at much lower temperatures, then undergoes a kinetic transition to a dynamically arrested state with broken ergodicity. This transition from a transient to a frozen gel is characterised by dynamical signatures reminiscent of jamming in much denser dispersions.