A Comparative Spectroelectrochemical Study of the Redox Electrochemistry of N- (Polyvinylamine)-Substituted-O-Nitroaniline

摘要

The electrochemistry and spectroelectrochemistry of polyvinylamine (PVAm) and Af-(polyvinylamine)-substituted-o-nitroaniline at a polycrystalline gold electrode in contact with different electrolyte solutions (0.1 M HC1O_4 and 0.1 M KClO_4) have been investigated with cyclic voltammetry and surface enhanced Raman spectroscopy (SERS). Cyclic voltammograms recorded with in acidic electrolyte solution showed formation of JV-(polyvinyl-amine)-o-phenylenediamine in the negative going potential scan; in neutral solution reduction proceeds only to N-fpolyvinylamine)o-phenylhydroxylamine. Vibrational modes are discussed and assigned to monomer-surface interactions of adsorbates at the gold surface in both electrolyte solutions. A variety of adsorption behaviors of these polymers at a gold surface is concluded; they apparently depend on the applied electrode potential, pH of electrolyte (acidic or neutral), type and mole percentage of the o-nitro-aniline moiety. The adsorption at the gold surface is strongly enhanced with 12.7 mole% of o-nitroaniline moiety, respectively, at its PVAm-backbone. The direct coordination of these polymers with the gold surface occurred via the nitro-group of the o-nitroaniline moiety and primary amino-groups located at the polymer backbone.