Photochromic supramolecular photonic crystals based on host–guest interactions

Abstract

A novel photo-responsive supramolecular hydrogel inverse opal material was described in this communication. The inverse opal material contains a host component β-cyclodextrin (β-CD) and a guest component 3-(acryloyl)amino-1,1′,5,5′-tetramethoxyazobenzen (MAzo). trans-MAzo has stronger association with β-CD than cis-MAzo. Under the irradiation of blue light (475 nm), the MAzo moieties transformed to the trans-configuration, resulting in blue-shift of the structural colour. In contrast, being irradiated with red light (620 nm) regulated MAzo to the cis-configuration and dissociated the host–guest pair; subsequently, the structural colour shifted to red. Therefore, in this system, the variation of the structural colour is in correspondence with the wavelength trend of the incoming light.