A novel photosensitive graft copolymer containing azobenzene chromophores in side chains was successfully achieved via the combination of two controlled polymerization methods

atom transfer radical polymerization (ATRP) and ring-opening metathesis polymerization (ROMP) with good control over the polymerization processes.ATRP of the azobenzene monomer initiated by an as-prepared inimer was first performed to generate a macromonomer

which was used in subsequent ROMP catalyzed by Grubbs third generation catalyst.The well-defined graft copolymers with grafts bearing azobenzene groups distributed on the same unit along the backbone were finally obtained by aforementioned strategy.As compared with typical macroinitiator syntheses of graft copolymers

the macromonomer synthetic approach allowed for precise architecture control.The structure and molecular weight of the graft copolymer were confirmed by MALLS-GPC and1H-NMR measurements.After ROMP

the molecular weight of the polymer was shifted to a high molecular weight position

and no peak attributed to the starting macromonomer was observed

indicating that the macromonomer had been completely converted to the graft copolymer.Besides

the obtained graft copolymer bearing azobenzene chromophores showed the reversible photoisomerization process upon irradiation with UV or visible light.