Heterogeneous crystallization of hard-sphere colloids near a wall

Abstract

We investigate the most basic situation of heterogeneous crystallization: crystallization of hard-sphere colloids in the presence of a flat hard wall. Using a combination of confocal microscopy and nonequilibrium Brownian dynamics simulations, microscopic time-resolved information is obtained on an individual-particle level. Initially, particles near the wall rearrange before an extended regime of crystal growth is found. During growth, we can directly observe a depletion zone in the fluid next to the progressing crystal–fluid interface due to the single-particle information provided by microscopy and simulations. This also allows us to follow the relaxation of the crystal layers and the progression of the crystal–fluid interface. In good agreement between our experiments and simulations, as well as previous studies, the growth rate shows a maximum in its dependence on the bulk volume fraction.