Solvent effects in the formation of hybrid materials based on titanium alkoxide-polysiloxane precursors

Abstract

Hybrid TiO₂-polysiloxane nanoparticles as well as hybrid TiO₂-polysiloxane gels were prepared and characterized applying solvent-induced aggregation effects of titanium alkoxide-modified polysiloxane block copolymers. The functionalized polymers were prepared by the covalent attachment of coordination sites that allow the binding to metal alkoxides (M(OR)₄; M = Ti; R = ethyl, butyl, isopropyl). Composition and structure of the hybrid polymers were investigated by NMR and FT-IR spectroscopy. In a second step the metal-alkoxide functionalities were hydrolyzed to form the respective metal oxides. Depending on the solvent in which the hydrolysis took place, hybrid nanoparticles or gels were obtained as a result of the different compatibility of the polysiloxane blocks towards the polarity of the solvents. The formed materials were investigated by NMR, FT-IR, atomic force microscopy (AFM), electron microscopy, and dynamic light scattering (DLS).