Morphological conversions of nanostructures in monolayers of an ABA triblock copolymer having azobenzene moiety

We report herein the microphase separation structures (nanostructures) observed in Langmuir-Blodgett monolayers of an ABA block copolymer comprising of azobenzene-containing methacrylate and poly(ethylene oxide) as A and B block, respectively. After spreading this polymer on water in the trans and cis form of azobenzene, the monolayer is transferred onto mica at 1 mN m−1. The morphological features are observed by atomic force microscopy. The features of the nanostructures formed in the monolayers have obviously different features in the isomerization state of azobenzene. The conversions of the morphological features accompanied by the isomerization of azobenzene are attempted by light irradiation and dark adaptation. This paper focuses on the features in morphological conversions attained in the photo- and thermal processes.