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 induced graft copolymerization with acrylic acid(AAc), and covalent immobilization of the enzyme trypsin were characterized by angle-resolved X-ray photoelectron spectroscopy(XPS). Both ozone and Ar plasma treatment result in the oxidation of carbon atoms and cause a significant decrease in the intrinsic oxidation states ([=N-]/[-NH-] ratio) of the base polymers. Surface graft copolymerization with AAc readily gives rise to self-protonated PANi and PPY surface structures. The concentration of surface grafted AAc polymer increases with increasing monomer concentration and near-UV irradiation time used during grafting, but decreases with Ar plasma pretreatment time. Covalent immobilization of trypsin 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 high AAc polymer concentration.