Crystallization Kinetics of Colloidal Spheres under Stationary Shear Flow

TL;DR

This study investigates how steady shear flow influences nucleation, crystal growth, and phase behavior in charged colloidal spheres, revealing non-monotonic effects and maxima in growth rates and induction times.

Contribution

It provides the first systematic experimental analysis of shear effects on colloidal crystallization and phase diagrams, highlighting non-linear behaviors.

Findings

Crystal growth rate peaks at an optimal shear rate.

Maximum crystal growth rate occurs at specific concentrations under shear.

Induction time shows a maximum as a function of shear rate.

Abstract

A systematic experimental study of dispersions of charged colloidal spheres is presented on the effect of steady shear flow on nucleation and crystal-growth rates. In addition, the non-equilibrium phase diagram as far as the melting line is concerned is measured. Shear flow is found to strongly affect induction times, crystal growth rates and the location of the melting line. The main findings are that (i) the crystal growth rate for a given concentration exhibits a maximum as a function of the shear rate, (ii) contrary to the monotonous increase of the growth rate with increasing concentration in the absence of flow, a maximum of the crystal growth rate as a function of concentration is observed for sheared systems, and (iii) the induction time for a given concentration exhibits a maximum as a function of the shear rate. These findings will be partly explained on a qualitative level.