Light-induced macroscopic chirality in thin films of achiral main-chain amorphous polyazourea system

We have demonstrated circularly polarized light-induced chirality in polymer thin films containing azobenzene linkages in their main-chain backbone. The material used in this study was an amorphous main-chain polyazourea with a high glass transition temperature, which was used to form the fine surface relief gratings. The induction of chirality was confirmed by measuring circular dichroism spectra of achiral polyazourea thin films irradiated with right or left circularly polarized light and was discussed in view of the massive displacement of the material. The repeatability and thermostability of the induced chirality were evaluated and compared with those of the polymers with azobenzene moieties in their side chains.