Self-Assembly and Autopolymerization of Pyrrole and Characteristics of Electrodeposition of Polypyrrole on Roughened Au(111) Modified by Underpotentially Deposited Copper

By combining techniques of underpotential deposition (UPD) and roughening metal substrates by a triangularwave oxidation-reduction cycle (ORC) which is generally used in surface-enhanced Raman scattering (SERS) studies, and extending applications of self-assembled monolayers (SAMs), copper is underpotentially deposited on electrochemically roughened Au(111) in this study for the first time. The formation of SAMs and further autopolymerization of pyrrole monomers are found on the UPD Cu-modified gold surfaces. The stability of SAMs is significantly improved due to the presence of UPD Cu. Furthermore, electropolymerized polypyrrole (PPy) on this UPD Cu-modified roughened Au demonstrates some distinguishing properties. These include higher conductivities, higher intensity, and better resolution on SERS and improved anti-aging ability in a 50% relative humility, 20% (v/v) O₂ atmosphere at 30 °C for 60 days.