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.
@article{arxiv.cond-mat/0409114,
title = {Shear Excitation of Confined Colloidal Suspensions},
author = {Itai Cohen and Thomas G. Mason and David A. Weitz},
journal= {arXiv preprint arXiv:cond-mat/0409114},
year = {2009}
}