PhotoResponsive Polymer Networks Based on α-Cyclodextrin Inclusion Association

Two polymers, αCD and azobenzene modified poly(acrylic acid)s (αCDPAA and azoPAA) were prepared and characterized by 1HNMR. The photoresponsive polymer networks were prepared by macromolecular assembly based on the inclusion associations between azo and αCD grafts after mixing aqueous solutions of αCDPAA and azoPAA. Under irradiation of 365 nm UV light, viscosity of the network decreased by nearly one order of magnitude, while recovered after keeping the sample in dark for some time. The viscosity change was reversible and repetitive under UV irradiation and in dark. The viscosity change was due to the cis/trans transition of azo group under UV irradiation as studied by NMR and UVVis absorption spectra.