Mesoscopic model for colloidal particles, powders and granular solids

TL;DR

This paper introduces a mesoscopic simulation model for colloids, powders, and granular solids that captures complex behaviors like phase coexistence, fracture, and glass formation with a simple, efficient approach.

Contribution

The model combines elastic spheres with short-range attraction and frictional forces, enabling realistic simulation of diverse particulate systems with parameters linked to experiments.

Findings

Predicts correct scaling for granular fracture

Displays a schematic phase diagram with liquid-vapor coexistence

Reveals stable solid-vapor coexistence at small attraction ranges

Abstract

A simulation model is presented, comprising elastic spheres with a short range attraction. Besides conservative forces, radial- and shear friction, and radial noise are added. The model can be used to simulate colloids, granular solids and powders, and the parameters may be related to experimental systems via the range of attraction and the adhesion energy. The model shares the simplicity and speed of Dissipative Particle Dynamics (DPD), yet the predictions are rather non-trivial. We demonstrate that the model predicts the correct scaling relations for fracture of granular solids, and we present a schematic phase diagram. This shows liquid-vapor coexistence for sufficiently large interaction range, with a surface tension that follows Ising criticality. For smaller interaction range only solid-vapor coexistence is found, but for very small attractive interaction range stable liquid-vapor coexistence reappears due to pathological stability of the solid phase. At very low temperature the model forms a glassy state.