Regiospecific accumulation of photofunctional units at microphase segregation interface of amphiphilic diblock copolymer

The amphiphilic diblock copolymer of poly(ethylene oxide) (PEO) and poly(methacrylate) bearing azobenzene liquid crystalline units (PMA(Az)) gave a well-aligned cylindrical nanostructure, in which both PEO and PMA domains were bicontinuous throughout the film thickness. A point-functionalized block copolymer with photo- and electrochemically active perylenediimide PEO ₁₁₄-Jb-pery-Jb-PMA(Az)_n was synthesized by atom transfer radical polymerization with narrow polydispersity of 1.15. The spin-cast film from chloroform solution gave a hexagonally aligned but mono-directionally distorted cylindrical nanostructure throughout the film thickness. The fact that the relative intensity of the fluorescence at 638 nm, which is assigned as dimer emission of perylenediimide, was enhanced upon annealing implies that the strongly n-n stacked structure of perylenediimide was formed at the interface of PEO and PMA domains during the formation of aligned nanostructure.