title: Robust ion-permselective multilayer films prepared by photolysis of polyelectrolyte multilayers containing photo-cross-linkable and photolabile groups.
abstract: The azobenzene-containing polyanion PAC-azoBNS was alternately assembled with the polycation diazoresin (DAR) to construct photo-cross-linkable multilayer films of PAC-azoBNS/DAR that contain photolabile groups of azobenzene. Upon mild UV irradiation, the interaction between PAC-azoBNS/DAR multilayers was converted from electrostatic interaction to covalent bonds. Because of the free carboxylic acid groups presented in the film, the photo-cross-linked multilayer film favors the selective permeation of positively charged species. After photolysis of the photo-cross-linked PAC-azoBNS/DAR films with intense UV irradiation, azobenzene groups decompose to produce imine groups, and a photo-cross-linked robust film containing free carboxylic acid and imine groups was fabricated. The resultant film allows the permeation of negatively charged species and meanwhile shows a pH-switchable permselectivity for positively charged species. Because of the covalently cross-linking structure, the photolyzed cross-linked PAC-azoBNS/DAR film shows high reversible switching behavior and has high stability in solution with high ionic strength.
authors.affiliation: Key Lab of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, P R China 130012.
authors.forename: En-Hua
authors.initials: EH
authors.lastname: Kang
authors.forename: Xiaokong
authors.initials: X
authors.lastname: Liu
authors.forename: Junqi
authors.initials: J
authors.lastname: Sun
authors.forename: Jiacong
authors.initials: J
authors.lastname: Shen