Local structure of percolating gels at very low volume fractions

TL;DR

This study uses numerical simulations to investigate the structure of percolating colloidal gels at very low volume fractions, revealing how local structures and interaction strength influence gel properties.

Contribution

It demonstrates that percolating gels can form at extremely low volume fractions and shows how interaction strength affects gel compactness and local structural features.

Findings

Gels form at very low volume fractions without hydrodynamic interactions.

Low interaction strength leads to more chain-like, less compact structures.

The fractal dimension of gels can be tuned by adjusting interaction strength.

Abstract

The formation of colloidal gels is strongly dependent on the volume fraction of the system and the strength of the interactions between the colloids. Here we explore very dilute solutions by the means of numerical simulations, and show that, in the absence of hydrodynamic interactions and for sufficiently strong interactions, percolating colloidal gels can be realised at very low values of the volume fraction. Characterising the structure of the network of the arrested material we find that, when reducing the volume fraction, the gels are dominated by low-energy local structures, analogous to the isolated clusters of the interaction potential. Changing the strength of the interaction allows us to tune the compactness of the gel as characterised by the fractal dimension, with low interaction strength favouring more chain-like structures.