Periodic structures in colloidal crystals with oscillatory flow

Abstract

We have studied some aspects of the flow of colloidal crystals in a capillary. Applying oscillatory pressure we induce flow in the shear region near where the crystal responds plastically. Under certain conditions, we observe well oriented crystalline regions which alternate orientations in a periodic pattern along the tube. Since the crystals have a lattice spacing of approximately 0.5 μ and Bragg scatter visible light, a periodic colour pattern is observed. We have studied the formation of these cylindrically symmetric striations as a function of shear modulus, frequency and amplitude of oscillations, particle size and tube diameter