Elasticity of arrested short-ranged attractive colloids: homogeneous and heterogeneous glasses

TL;DR

This paper presents a new analytical approach to evaluate the elasticity of arrested short-ranged attractive colloids, distinguishing between microscopic and mesoscopic contributions to their shear modulus, and classifying arrested states as homogeneous or heterogeneous glasses.

Contribution

The authors develop a hierarchical arrest scheme combined with an elastic model to differentiate microscopic and mesoscopic elastic contributions in colloidal glasses.

Findings

Quantitative agreement with experimental data across volume fractions.

Identification of conditions where mesoscopic structures dominate elasticity.

Proposal to classify arrested states as homogeneous or heterogeneous based on elastic length scales.

Abstract

We evaluate the elasticity of arrested short-ranged attractive colloids by combining an analytically solvable elastic model with a hierarchical arrest scheme into a new approach, which allows to discriminate the microscopic (primary particle-level) from the mesoscopic (cluster-level) contribution to the macroscopic shear modulus. The results quantitatively predict experimental data in a wide range of volume fractions and indicate in which cases the relevant contribution is due to mesoscopic structures. On this basis we propose that different arrested states of short-ranged attractive colloids can be meaningfully distinguished as homogeneous or heterogeneous colloidal glasses in terms of the length-scale which controls their elastic behavior.