Development of Photo-functional Materials from Organic/Inorganic Nano-Hybrids

Abstract

Organic/inorganic nano-hybrids are molecularly dispersed composite materials with polymers and metal oxides. As these materials have excellent transparency, they are expected to be applied for the optical usage. In particular, organic/inorganic hybrids with photo-functional polymers would be interesting materials with optical properties. Polysilanes are one of photo-functional polymers, whose functions are photodegradation, photoconductive, high refractive index, etc. We have been investigating about the preparation and properties of the novel nano-hybrids of polysilane with inorganic substances. Polymethylphenylsilane (PMPS)/silica or titania nano-hybrid thin films were prepared by a sol-gel reaction with PMPS block copolymers and corresponding metal alkoxides. The refractive index of nano-hybrid thin films could be controlled with the composition ratio of PMPS. After development of the UV-irradiated hybrid thin films with organic solvents, nano porous (ca. 20 nm) silica or titania thin films were obtained by removing the decomposed PMPS segments, and a high refractive index difference occurred between irradiated and non-irradiated part in the hybrid thin films. Furthermore, a hybrid thin film of polydihexylsilane (PDHS) and zirconia suppressed the thermochromism which is known as a characteristic of polydialkylsilane, and this hybrid thin film provided the high thermo-optic (TO) effect with an advantage for optical devices.