SURFACE-FUNCTIONALIZED POLYANILINE FILMS

The surfaces of emeraldine (EM) base films of polyaniline (PANi) have been functionalized by thermal graft copolymerization with acrylic aci d (AAc) and N,N-dimethyl(methacryloylethyl)ammonium propanesulfonate ( DMAPS), The AAc graft copolymerized EM films were further functionaliz ed via covalent immobilization of glucose oxidase (GOD) and collagen. The so-immobilized GOD still retains a substantial amount of activity. The amphoteric DMAPS graft copolymerized EM base films are capable of exhibiting strong adhesive-free adhesion to one another and to anothe r similarly modified dielectric film, such as a surface graft copolyme rized poly(tetrafluoroethylene) (PTFE) film. Lap shear adhesion streng ths on the order of 300 and 100 N/cm(2) were obtained for the respecti ve cases, Pristine PANi films of various intrinsic oxidation states ar e capable of undergoing spontaneous surface metallization through redu ction of precious metal ions, such as gold and palladium, in acid solu tions to their elemental forms. The rate of metal reduction is favored by a low intrinsic oxidation state of the polymer, The surface compos ition and microstructure of the polymer films after modification, func tionalization, and metallization were characterized by angle-resolved X-ray photoelectron spectroscopy (XPS).