Methacrylate copolymers with substituted azobenzene side groups: synthesis, characterization and photo-induced birefringence properties

摘要

Well-defined copolymer of methyl methacrylate (MMA) and 2-methylacrylic- acid-2-{ethyl-[4-(4-methoxy-phenylazo)-3-methyl-phenyl]-amino}-ethyl ester (MAMP) bearing pendent azobenzene groups, was synthesized via reversible addition-fragmentation chain transfer polymerization (RAFT). Copolymers with different contents of azobenzene moieties, e. g. from 12 mol % to 100 mol %, were obtained by varying the feed molar ratios of MAMP and MMA. The reactivity ratios of these two monomers were measured and calculated via the modified Kelen- Tüdos method. Glass transition temperature of the copolymers was measured by differential scanning calorimetry (DSC). Photoinduced trans-cis isomerization of azobenzene moieties in the copolymer was studied at room temperature. Films cast from the functional copolymers were characterized by photo-induced birefringence and surface relief grating (SRG).