SURFACE MODIFICATIONS OF POLYANILINE FILMS BY GRAFT-COPOLYMERIZATION

Both pristine and argon plasma pretreated emeraldine (EM) base films have been subjected to near-UV-light-induced graft copolymerization with acrylamide (AAm), the sodium salt of 4-styrenesulfonic acid (NaSS), and acrylic acid (AAc). The structure and chemical composition at each copolymer surface and interface are studied by angle-resolved X-ray photoelectron spectroscopy (XPS). In each case, the density of surface grafting is enhanced by plasma pretreatment. Surface grafting with the three polymers also leads to a more hydrophilic EM film. Furthermore, grafting with the NaSS and AAc polymers readily gives rise to a self-doped or self-protonated EM surface structure. However, a substantial proportion of the grafted protonic acid groups at the surface remains free for further surface modification and functionalization.