Enzymatic synthesis of photoactive poly(4-phenylazophenol)

Enzymatic synthesis, employing horseradish peroxidase (HRP), has been used to prepare a novel photoactive azopolymer, poly(4-phenylazophenol), from 4- phenylazophenol, FTIR, FT-Raman, and NMR (H-1, C-13) spectroscopy show that the coupling reaction occurs primarily at the ortho positions with some co upling at the meta positions of the phenol ring of the monomer as well. Thi s results in the formation of a branched polyphenylene backbone with pendan t azo functionalities on every repeat unit of the macromolecules. This enzy matically synthesized azophenol polymer has an extremely high dye content ( nearly 100%) and is soluble in most polar organic solvents, and good optica l quality thin films are easily formed. Polymer solutions show reversible t rans to cis photoisomerization of the azobenzene groups with long relaxatio n time. The poly(azophenol) film exhibits photoinduced absorption dichroism and large photoinduced birefringence with unusual relaxation behavior. The resulting azobenzene loaded polymer behaves as a new type of glassy "macro molecular dye".