Polyelectrolyte layered assemblies containing azobenzene-modified polymer and anionic cyclodextrins

Sulfonated cyclodextrins (s-alpha-CyD and s-beta-CyD) were employed for constructing photosensitive thin films containing azobenzene residues. Azobenzene-modified poly(allylamine hydrochloride) (Az-PAH) and s-alpha-CyD or s-beta-CyD were deposited alternately on the surface of a quartz slide to prepare multilayer thin films. Az-PAH formed inclusion complex in the Az-PAH/s-alpha-CyD film but not in the Az-PAH/s-beta-CyD film. The Az-PAH isomerized from E- to Z-isomer in the films under UV light irradiation, and the original E-form was recovered under visible light irradiation or thermally in dark. The thermal isomerization followed the first-order kinetics in the swelled films though the kinetics deviated from the first-order plot in the dry films. The host-guest complexation of Az-PAH and s-alpha-CyD in the film affected significantly on the photochemical and thermal isomerization. (C) 2003 Elsevier B.V. All rights reserved.