Photo-induced micellization of block copolymers bearing 4,5-dimethoxy-2-nitrobenzyl side groups

The synthesis of photocleavable poly(dimethoxynitrobenzyl acrylate)-block-polystyrene block copolymers is described. The UV irradiation of these block copolymers, dissolved in a good solvent for both blocks, selectively cleaves the dimethoxynitrobenzyl protecting groups, leading to carboxylic acid moieties. Since the resulting hydrophilic poly(acrylic acid) block is insoluble in the solvent used, self-assembly of the diblocks into micelles is observed. This light-induced micellization process is further used to trap dyes into the core of the micelles.