ELECTROOPTIC EFFECTS IN COLLOIDAL CRYSTALS OF SPHERICAL SILICA PARTICLES

The electro-optic behavior of isotropic colloidal crystals of spherica l silica particles is investigated by the electric light-scattering me thod. The electro-optic responses observed at low frequencies (hertz r ange) are consistent with particle concentration fluctuations induced by charge transport and convection. A resonance frequency is detected, at which the decay of the electro-optic response is viscoelastic. The increase of held intensity introduces electrohydrodynamic effects sim ilar to those observed in the liquid crystals. (C) 1995 Academic Press , Inc.