The role of friction in the yielding of adhesive non-Brownian suspensions

TL;DR

This paper investigates how friction influences the yielding behavior of adhesive non-Brownian suspensions, revealing that yielding involves unjamming from a shear-jammed state rather than just breaking bonds, with implications for flow control.

Contribution

It demonstrates the critical role of friction in the yielding process of adhesive suspensions and connects microstructural unjamming to shear behavior, expanding understanding beyond bond-breaking models.

Findings

Friction significantly affects the yield stress of suspensions.

Yielding involves unjamming from a shear-jammed state.

Frictional interactions can be tuned to control flow properties.

Abstract

Yielding behavior is well known in attractive colloidal suspensions. Adhesive non-Brownian suspensions, in which the interparticle bonds are due to finite-size contacts, also show yielding behavior. We use a combination of steady-state, oscillatory and shear-reversal rheology to probe the physical origins of yielding in the latter class of materials, and find that yielding is not simply a matter of breaking adhesive bonds, but involves unjamming from a shear-jammed state in which the micro-structure has adapted to the direction of the applied load. Comparison with a recent constraint-based rheology model shows the importance of friction in determining the yield stress, suggesting novel ways to tune the flow of such suspensions.