SURFACE-MODIFIED AND FUNCTIONALIZED POLYANILINE AND POLYPYRROLE FILMS

Surface modified and functionalized polyaniline (PANi) and polypyrrole (PPY) films from ozone treatment, Ar plasma treatment, near-UV-light i nduced graft copolymerization with acrylic acid(AAc), and covalent imm obilization of the enzyme trypsin were characterized by angle-resolved X-ray photoelectron spectroscopy(XPS). Both ozone and Ar plasma treat ment result in the oxidation of carbon atoms and cause a significant d ecrease in the intrinsic oxidation states ([=N-]/[-NH-] ratio) of the base polymers. Surface graft copolymerization with AAc readily gives r ise to self-protonated PANi and PPY surface structures. The concentrat ion of surface grafted AAc polymer increases with increasing monomer c oncentration and near-UV irradiation time used during grafting, but de creases with Ar plasma pretreatment time. Covalent immobilization of t rypsin on the AAc polymer grafted PANi and PPY films is facilitated by the presence of water-soluble carbodiimide (WSC). The activity of the immobilized enzyme increases initially with increasing concentration of surface grafted AAc polymer, but becomes saturated at moderate to h igh AAc polymer concentration.