Solvent Effects in the Deaggregation of Titania Nanoparticles

Abstract

We report on the effect of alcohols in the acid peptization of aggregated titania nanoparticle produced from alkoxides. Peptization was studied in the presence of each one of the following alcohols: methanol, ethanol, propanol and isopropanol. We find that the final particle size is correlated to the dielectric constant of the peptizing medium. Kinetic measurements reveal that the rate of deaggregation is not affected by the presence of alcohol; however, the tendency for reaggregation of the peptized colloid increases significantly. We conclude that alcohols prevent the full redispersion of the aggregates by decreasing the colloidal stability of the suspension. This conclusion is supported by the measured zeta potential of the peptized particles, which is found to decrease when alcohol is present.