Shear Excitation of Confined Colloidal Suspensions

TL;DR

This paper investigates how geometric confinement influences shear-induced structures in dense colloidal suspensions, revealing new buckled layered configurations and proposing a model to explain the interplay between packing and shear stress.

Contribution

It introduces a model explaining the effects of confinement on shear-induced particle arrangements in colloidal suspensions, highlighting the emergence of buckled layers.

Findings

Confinement leads to buckled layered structures in colloids.

Volume fraction is governed by viscous and osmotic pressures.

A new model explains the interplay between packing and shear stress.

Abstract

We show that geometric confinement dramatically affects the shear-induced configurations of dense mono-disperse colloidal suspensions; a new structure emerges, where layers of particles buckle to stack in a more efficient packing. The volume fraction in the shear zone is controlled by a balance between the viscous stresses and the osmotic pressure of a contacting reservoir of unsheared particles. We present a model that accounts for our observations and helps elucidate the complex interplay between particle packing and shear stress for confined suspensions.