Parameters involved in the sol-gel transition of titania in reverse micelles

Titania nanoparticles and gels are synthesized in reverse micelles with eit her an ionic (AOT) or a nonionic (Triton X-100) surfactant in alkanes with low water contents. Acids were in some cases dissolved in the aqueous phase . Whereas the size of the sol nanoparticles is independent of the micellar composition, the kinetics of the sol-gel transition are not. The gelation t ime is shorter for the non-ionic surfactant and becomes longer as the acid content in the water increases, and for smaller anions of equal charge.