Polyhedral colloidal `rocks': low-dimensional networks

TL;DR

This paper introduces a model of anisotropic colloidal rocks with rigid bonds, revealing unique low-dimensional network structures and glass formation due to their shape-induced frustration, contrasting with spherical colloid gels.

Contribution

The study presents a geometric model and experimental validation for anisotropic colloidal rocks, highlighting their distinct structural and dynamical properties compared to spherical colloids.

Findings

Rocks form low fractal dimension networks.

Rigid bonds induce strong frustration.

High-density rocks form a quasi one-component glass.

Abstract

We introduce a model system of anisotropic colloidal `rocks'. Due to their shape, the bonding introduced via non-absorbing polymers is profoundly different from spherical particles: bonds between rocks are rigid against rotation, leading to strong frustration. We develop a geometric model which captures the essence of the rocks. Experiments and simulations show that the colloid geometry leads to structures of low fractal dimension. This is in stark contrast to gels of spheres, whose rigidity results from locally dense regions. At high density the rocks form a quasi one-component glass.