Development of Functional Organic Coating with Self -Repair Ability for Future Corrosion Resistance Film

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The effects of electrolysis factors on the formation of poly(2vinylpyridine) coatings electropolymerized on Zn substrate have been investigated by cyclic voltammetry technique. The amount of poly(2-vinylpyridine) coatings electropolymerized by cyclic voltammetry was significantly dependent on the pH of the bath and the maximum amount of coating was obtained at pH5. This result suggested that the specific amount of proton in the bath should play an important role in the electropolymerization of 2-vinylpyridine. The morphology of the coatings was evidently affected by the hydrogen evolution. Under the electrolysis conditions where the hydrogen evolution rate was increased, the coatings contained many pits and streaks caused by vigorous hydrogen evolution. The poly(2-vinylpyridine) coatings produced by cyclic voltammetry were fine in the bath of pH5 at 20 to 30℃. On the other hand, the current density for polymerization by chronoamperometry was abruptly decreased in the initial stage of t … More wo-dimensional coating formation, then it was subsequently decreased with an increase in the thickness of sound coating. The anode and cathode current density of Zn plate in 3% NaCl solution was decreased by poly(2-vinylpyridine) coating formation on it.The poly(2vinylpyridine) films were electropolymerized on Zn substrate by galvanostatic technique at 30 ℃ in the pH5 aqueous solution containing methanol. The films were also formed by cyclic voltammetry and potentiostatic techniques and were compared with those by galvanostatic electrolysis. The thickness of films formed by galvanostatic electrolysis was increased in proportion to the amount of coulombs but decreased with increasing the current density because of an increase in hydrogen evolution. Based on the FT-IR spectra and the color of films, it was presumed that the structure of poly(2-vinylpyridine) films was changed from non-branched to branched chain type with an increase in current density. The anodic current density for Zn dissolution in 3% NaCl solution were significantly decreased by coating poly(2-vinylpyridine) films. At 50A/m^2 of electropolymerization, the anodic reaction was most inhibited, showing the excellent corrosion resistance. Although the electrochemical techniques had no effect on the thickness and the structure of films, the films formed by galvanostatic electrolysis contained the least cracks to most improve the corrosion resistance. Less