Strategy and characteristics of polypyrrole deposited on silver substrates with silver-containing nanocomplexes

In this study, we provide a strategy to electrodeposit polypyrrole (PPy) on roughened silver substrates, which was accomplished by a triangular-wave oxidation-reduction cycle (ORC) for three scans in an aqueous solution containing 0.1 N KCl. This method overcomes the conventional limitation that silver, oxidizing more readily than the pyrrole monomer, would obviously not be a good choice for the anode in the electropolymerization of PPy. It was found that Cl- and Ag-containing nanocomplexes with grain sizes smaller than 100 nm were formed on the roughened Ag substrates after ORC treatment. Meanwhile, pyrrole monomers can form self-assembled monolayers (SAMs) and further autopolymerization on these nanocomplexes. As shown in the Fourier transform infrared (FTIR) spectrum, charge transfer occurs from electrodeposited pyrrolylium nitrogen to the roughened silver. The autopolymerized PPy owns a high conductivity, as confirmed by the analyses of X-ray photoelectron spectroscopy (XPS) and surface-enhanced Raman scattering (SERS).