Photochromic Block Copolymer Poly(styrene-b-azo monomer) by ATRP

Photoactive monomers [(E)-1(4-methacryloxyphenyl)-2-(nitrophenyl) diazene] (azo 1 ) and (E)-1-(4-methacryioxyethy!-pheny!)-2-phenyi-diazene (azo2) were synthesized. The azo 1 monomer showed poor reactivity under the evaluated polymerization method. The Azo 2 monomer was used in the block copolymerization with polystyrene by the normal ATRP methodology. Several polystyrene macroinitiators were prepared with molecular weights of 10, 20 and 30 k g/mol. The end functionality was increased by the addition of 0.1 equivalents of copper II chloride. Block copolymers in 30% yield and low polydispersity were synthesized by ATRP from the polystyrene macroinitiators and the azo monomer. The block copolymer exhibits good photochromic activity.