Formation of poly (2-vinylpyridine) films on Zn by galvanostatic electropolymerization

Abstract

Poly(2-vinylpyridine) films were deposited on Zn substrate by electropolymerization using galvanostatic technique at 30°C in pH 5 aqueous solution containing methanol. Films were also formed by employing cyclic voltammetry and potentiostatic techniques; these were compared with those formed using galvanostatic electrolysis. The thickness of films formed by galvanostatic electrolysis increased in proportion to the amount of charge passed during electropolymerization but decreased with increasing current density because of increased hydrogen evolution. The FT-IR spectra and the color of the films suggested that the structure of poly (2-vinylpyridine) films changed from the non-branched to the branched chain type with the higher current densities. The anodic current density for Zn dissolution in 3%NaCl solution was significantly decreased by coating with poly (2-vinylpyridine) films. After electropolymerization at 50A · m -2, the anodic reaction was most inhibited, showing excellent corrosion resistance. Although the electrochemical techniques employed for the film preparation had no influence on the thickness or the structure of films, the films formed by galvanostatic electrolysis contained the fewest cracks and gave the best corrosion resistance. © 2005 The Japan Institute of Metals.