Photo-Induced Photonic Band Gap Shift of SiO2 Inverse Opal Films Infiltrated by Azo-Tolane Copolymer

Photochemically tunable photonic band gap materials were prepared by the infiltration of liquid crystal polymers with azobenzene side chains and tolane side chains indicating larger birefringence into voids of SiO2 inverse opal films. Linearly polarized light irradiation resulted in transformation from random to anisotropic molecular orientation of azobenzene and tolane side chains, then the azobenzene-tolane copolymer film showed larger birefringence. Thus, the reflection band of the SiO2 inverse opal films infiltrated with the azobenzene-tolane copolymers was shifted to longer wavelength region by the irradiation of linearly polarized light.