Photoswitching behavior of sio2 inverse opal films infiltrated with azo-tolane copolymer: Effect of polymer main chain structure

Phototunable photonic band gap materials were prepared by infiltration of a liquid crystalline azopolymer into voids of a SiO2 inverse opal film. Linearly polarized light irradiation resulted in a reversible and stable shift of the reflection band to longer wavelength region due to the transformation of azobenzene groups from random to anisotropic molecular orientation. Acrylate and methacrylate copolymers having both azobenzene and tolane groups in side chain have been synthesized in order to improve switching property. Upon irradiation of linearly polarized light SiO2 inverse opal film infiltrated with methacrylate copolymer showed a larger wavelength shift of the reflection band compared to that of the composite film infiltrated with acrylate copolymer.