KINETICS OF CRYSTALLIZATION IN A SHEARING COLLOIDAL SUSPENSION

We report the kinetics of crystallization as observed in simulations o f a charged colloidal suspension under shear. We find that the imposed shear how inhibits crystal nucleation. Crystallization was only obser ved for shear rates at or below gamma tau(0) = 0.07 (where tau(0) is t he time required for a particle to diffuse the averge interparticle di stance in a dilute suspension). Under the influence of these low shear rates the suspension crystallizes into a single shear-aligned crystal , as opposed to the polycrystalline structure found in the absence of shear flow. Crystal growth is found to be proportional to the effectiv e supercooling, as measured from the melting temperature of the sheari ng crystal. We conclude that, by analogy with the case of crystallizat ion at zero shear, the effective supercooling provides an operational measure of the ''thermodynamic'' stability of the shearing crystal.