Preparation of inorganic-organic hyhrid titania sol-gel nanocomposite films, and their dielectric properties

Hybrid titania materials were prepared by a process involving the phase separation of TiO2 by hydrolysis and polycondensation from hybrids between titanium tetraisopropoxide (TTIP) and 3-(methacryloyloxy)propyl trimethoxysilane (MPTS) with excess acidic water at an elevated temperature (80 degrees C). The formation of TiO2 nanoparticles within the hybrid materials was studied as a function of the ageing time as well as the Ti/Si molar ratio. The crystalline phases of the TiO2 nanoparticles formed in situ within the inorganic-organic hybrid matrix were characterized by X-ray diffraction and Fourier transform infrared studies. The microstructures and the morphologies of thick films of the hybrid materials were studied using scanning and transmission electron microscopy, which showed the existence of nanocrystalline TiO2 within the crack-free hybrid matrix. The dielectric constants of the composites were found to be in the range 5.0-7.1, depending on the measuring frequency and the composite composition. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.