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In this work, polypyrrole (PPy) films were electrodeposited on electrochemically roughened gold substrates modified by argon plasma treatment. First, a gold substrate was roughened by a triangular-wave oxidation-reduction cycle (ORC) in an aqueous solution containing 0.1 N HCl. Then the roughened gold substrate was further treated by argon plasma. Encouragingly, the surface-enhanced Raman scattering (SERS) spectroscopy of polypyrrole electrodeposited on this roughened gold substrate modified by argon plasma treatment exhibits a higher intensity by 8-fold, as compared with the SERS of PPy electrodeposited on an unmodified roughened gold substrate. Meanwhile, the electropolymerization for pyrrole monomers occurring on the modified roughened gold substrate is easier. Also, the nucleation and growth of electropolymerization of pyrrole monomers on the modified and unmodified gold substrates are different.

We report here the first electrochemical method to prepare a roughened gold substrate with bimetallic silver and gold nanoparticles. First, a silver substrate was roughened by a triangular-wave oxidation-reduction cycle in 0.1 N HCl aqueous solutions. Silver-containing complexes were found in the solution after the ORC treatment. Then a gold substrate was subsequently roughened by a similar oxidation-reduction treatment in this solution. Scanning electron microscopy and atomic force microscopy reveal that the surface of the roughened gold was intrinsically modified with silver nanoparticles, which demonstrates two different kinds of deposition domains. Encouragingly, surface-enhanced Raman scattering of polypyrrole electrodeposited on the roughened gold substrate, modified with finer silver nanoparticles, exhibits an eightfold higher intensity.

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