Crystallization of Charged Colloids under Microgravity during Aircraft Parabolic Flights

Abstract

We studied crystallization process of charged colloids under microgravity (μG) by performing time resolved reflection spectroscopy, during aircraft parabolic flight experiments. We used dilute colloidal silica samples (specific gravity of the particles = 2.1, the particle concentration = 1 - 2 vol.%) that crystallized from shear-melt colloids, within the duration time of μG (approximately 20 seconds). An influence of μG was found to be less significant for the heterogeneous nucleation process with the aid of the cell walls. The incubation times of the homogeneous nucleation, τ, at μG was longer than that at 1G. Furthermore, the half-widths of the Bragg diffraction peaks from the crystals were narrower by 30% at the largest, under μG. This suggests that the crystal grain size (cross-sectional area) became larger under μG environment, according to the Scherrer's relation.