PHOTOELECTRORHEOLOGY OF TIO2 NANOPARTICLE SUSPENSIONS

The electrorheological properties of a TiO2 (anatase) particle suspens ion in silicone oil were found to undergo changes during illumination, including an increased electrorheological effect, i.e., increased vis cosity upon illumination. The increased viscosity is due to the polari zation of photoinduced charge carriers under the influence of the impo sed electric field, A small photocurrent was observed, which can be at tributed to photoelectrophoretic conduction and leakage of photogenera ted charge through field-induced columns. Microscopic observation carr ied out under stationary conditions showed an increase in the number o f field-induced columns upon illumination, consistent with increased v iscosity.