Polyelectrolyte layered assemblies containing azobenzene-modified polymer and anionic cyclodextrins

Sulfonated cyclodextrins (s-α-CyD and s-β-CyD) were employed for constructing photosensitive thin films containing azobenzene residues. Azobenzene-modified poly(allylamine hydrochloride) (Az-PAH) and s-α-CyD or s-β-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-α-CyD film but not in the Az-PAH/s-β-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-α-CyD in the film affected significantly on the photochemical and thermal isomerization.