Attraction-enhanced emergence of friction in colloidal matter

TL;DR

This study investigates how microscopic friction emerges in colloidal systems, showing that increased particle coordination and attraction strength lead to frictional arrest, which can be tuned to modify material properties.

Contribution

It establishes a quantitative link between interparticle interactions, coordination, and frictional behavior in colloidal matter, advancing understanding of friction emergence at the microscale.

Findings

Frictional interactions cause exponential slowdown of particle orientation dynamics with increased coordination.

Friction strength can be tuned by varying attraction strength.

Quantitative relations between friction, coordination, and interparticle interactions are established.

Abstract

How frictional effects emerge at the microscopic level in particulate materials remains a challenging question, particularly in systems subject to thermal fluctuations due to the transient nature of interparticle contacts. Here, we directly relate particle-level frictional arrest to local coordination in an attractive colloidal model system. We reveal that the orientational dynamics of particles slows down exponentially with increasing coordination number due to the emergence of frictional interactions, the strength of which can be tuned simply by varying the attraction strength. Using a simple computer simulation model, we uncover how the interparticle interactions govern the formation of frictional contacts between particles. Our results establish quantitative relations between friction, coordination and interparticle interactions. This is a key step towards using interparticle friction to tune the mechanical properties of particulate materials.