Formation of a Highly Ordered Colloidal Microstructure upon Flow Cessation from High Shear Rates

Abstract

A model suspension of charged colloidal spheres exhibits anomalous modulus relaxations upon flow cessation from the shear-thickened state. Small angle neutron scattering (SANS) measurements indicate the development of a metastable crystalline state upon flow cessation from a disordered, shear-thickened state. The metastable state consists of a random stacking of tightly packed hcp planes of particles lying in the shear velocity-vorticity plane. These measurements suggest that the apparently disordered shear-thickened state may contain a high degree of latent order not apparent in the SANS measurements during flow.