Isomer-Dependent Properties of Poly(vinyl pyridine)-Based Films Grown on Copper Surfaces

The effect of poly(2-vinyl pyridine) (P2VP) and poly(4-vinyl pyridine) (P4VP) isomers on the growth of surface films on copper substrates was studied by electrochemical, spectroscopic, thermogravimentric, and microscopic methods. In acid environment (3% v/v acetic acid) and in the presence of KSCN, electrochemically generated copper cations reacted rapidly with SCN- and P2VP or P4VP, yielding coordination compounds, which deposited onto copper surfaces as films. The characteristies of such polymer-metal complexes (films) were markedly isomer-dependent. Cu(I)/P2VP/SCN- complexes with monovalent cations and sulfur-coordinated thiocyanate were obtained in the presence of P2VP, whereas the formation of Cu(II)/P4VP/SCN- complexes with divalent cations and nitrogen-coordinated thiocyanate was observed in the presence of P4VP. Interestingly, similar physical-chemical properties (electronic structure, stoichiometry, and thermal behavior) were observed for materials synthesized by electrochemical and chemical methods. These results suggest, therefore, that control over the surface properties of copper substrates can be achieved using electrosynthesized films based on different PVP isomers. Besides acting as effective protective barriers against aggressive media and thus reducing the metal dissolution (corrosion) kinetics, these materials are potentially attractive for other applications in which surface properties are paramount, such as in catalysis. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 215-225, 2009