Colloidal crystallization by a centrifugation method

Abstract

Colloidal crystals of high particle concentration were smoothly and continuously fabricated by simple centrifugation of a dispersion of polystyrene particles in water. The larger the applied centrifugal acceleration α at the bottom of the growing crystals (i.e., the interior wall of the container), the higher the growth rates are. The average grain sizes in the crystals increased with decrease in α, and below a critical value of α, we obtained relatively large columnar-shaped grains. The average volume fraction of the obtained colloidal crystals ϕave. increased with an increase in the dispersion’s KCl concentration CKCl: at α=82G, ϕave.=0.57 and 0.61 at CKCl=2×10−3 and 8×10−3molkg−1 water, respectively. The grain size also increased with an increase in CKCl. The maximum grain size in this study was greater than 0.3mm in width and 8mm in length.