Formation Mechanism of Uniform Spindle-Type Titania Particles in the Gel-Sol Process

Recently, as an application of the novel synthetic of monodisperse particies named the “gel-sol method”, uniform spindle-like titania particles of anatase type have been produced by a 2-step process, consisting of the first aging of an aqueous solution of a titanium-triethanolamine compound for 24 h at 100°C for the formation of a rigid hydrolyzed gel and the second aging for 72 h at 140°C for the nucleation and growth of the titania particles in the gel network (T. Sugimoto et al., J. Colloid Interface Sci., in press). In this paper, the study is focused on the characterization of the titanium-triethanolamine compound, gel. and final product titania, the formation mechanism of the titania panicles, and their size control.