PHOTOMODULATION OF THE HYDROPHILIC PROPERTIES OF ACRYLIC POLYMERS CONTAINING SIDE-CHAIN AZOBENZENE CHROMOPHORES

Partially hydrophilic polymers have been prepared by free-radical copo lymerization of trans-4-acryloyloxyazobenzene with N-tert-butylacrylam ide and N-isopropylacrylamide. A turbidimetric method has been adapted to investigate the dependence of the polymer hydrophilic-hydrophobic balance on chemical composition and extent of photoisomerization of si de-chain azobenzene chromophores. Irradiation at 366 nm of polymer sus pension in THF-water induces the isomerization of azobenzene groups fr om the planar apolar trans form to the nonplanar polar cis form. Corre spondingly, the solution turbidity is appreciably modified. Experiment al results are discussed in terms of polymer structural parameters. Su spension stability and the possibility of carrying out photochemical c ycles have been also investigated.