Nanodomains within bicontinuous silicone/water microemulsions retard TiO2 nanoparticle aggregation

Nanoparticles of TiO2 are used in a variety of applications because of their high refractive index and photocatalytic behaviour. We report that both the interactions between the surfactant and titanium alkoxide and templating provided by a microemulsion significantly retard the formation of visible TiO2 aggregates. TiO2 nanoparticles (<30nm) were prepared under mild, neutral conditions within water-in-oil and bicontinuous silicone microemulsions. The particles aggregated only slowly, as shown by UV absorption spectroscopy transmission electron microscopy, and particle sizing. Retarded particle growth is ascribed primarily to constricted domains provided by self-organization within a water/surfactant/silicone microemulsion.