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XPS Characterization of Surface Functionalized Electroactive Polymers
Author(s) -
Loh F. C.,
Tan K. L.,
Kang E. T.,
Kato K.,
Uyama Y.,
Ikada Y.
Publication year - 1996
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/(sici)1096-9918(19960916)24:9<597::aid-sia163>3.0.co;2-2
Subject(s) - copolymer , surface modification , polymer , carbodiimide , polymer chemistry , contact angle , x ray photoelectron spectroscopy , monomer , polyaniline , covalent bond , chemistry , grafting , materials science , chemical engineering , polymerization , organic chemistry , engineering , composite material
Surface modification and functionalization of polyaniline (PAN) and polypyrrole (PPY) films were achieved by Ar plasma treatment, near‐UV‐induced graft copolymerization with acrylic acid (AAc) and covalent immobilization of an enzyme (trypsin). The compositions and structures of the modified and functionalized polymer surfaces were characterized by angle‐resolved XPS. Argon plasma treatment results in minor oxidations of the carbon atoms but is accompanied by a significant decrease in the intrinsic oxidation state ([ = N − ]/[ − NH − ] ratio) of the polymers. Graft copolymerization with AAc readily gives rise to self‐protonated PAN and PPY surface structures. The surface concentration of the grafted AAc polymer increases with increasing monomer concentration and near‐UV irradiation time during grafting but decreases with increasing plasma pretreatment time. Covalent immobilization of trypsin on the AAc‐polymer‐grafted PAN and PPY films is facilitated by the use of water‐soluble carbodiimide intermediate (WSC). The effective enzyme activity increases initially with increasing surface concentration of the grafted AAc polymer, but becomes saturated at moderate to high AAc polymer concentration.