Isomerization behavior of aromatic azo chromophores bound to semicrystalline polymer films

The cis-trans isomerization of azo chromophores covalently bound to semicry stalline polymer films was investigated. Various azo chromophores were intr oduced onto the functionalized semicrystalline polymer films by a chemical transformation reaction and their isomerization behavior was investigated b y UV-visible spectroscopy and a contact-angle goniometer. The thermal Z --> E isomerization rate of the azo moiety covalently bound to low-density pol yethylene (LDPE) and polypropylene (PP) films was determined. The rate of t hermal isomerization was also compared between amorphous and semicrystallin e polymer films bearing azo chromophores. The effect of the intramolecular steric factor and the nature of chromophores was studied on the thermal iso merization rate of the polymer films. (C) 2001 John Wiley & Sons, Inc.