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

Abstract

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) O 2 atmosphere at 30 °C for 60 days.

Characterization and corrosion performance of poly(pyrrole-siloxane) films on commercial Al alloys

“…8) reveals marked undercoating corrosion for Ppy/AA6082, while a well-adhered film with corrosion products inside the polymer-filled pits is observed on AA2024. The nature of the reactions involved in the corrosion protection of Ppy/AA2024 at open circuit is not known, although copper under-potential deposition could be involved [38,49,50]. The above finding is in agreement with the work of Epstein et al [51], who attributed the higher performance of Pani on AA2024, compared to coated AA3003 and Al, to copper extraction from the alloy surface into the polymer film, thus reducing the galvanic coupling between aluminium and copper.…”

Electrochemical functionalisation of SWNTs with poly(3,4‐ethylenedioxythiophene) evidenced by anti‐Stokes/Stokes Raman spectroscopy

“…As observed in Ref. [37], the UV-vis-NIR spectra of PEDOT indicate, for the excitation wavelength of 514.5 nm, a high absorbance for PEDOT in the un-doped state and a small absorbance for the polymer in the doped state, while for λ exc = 676.4 nm a high value of absorbance is observed for PEDOT, both undoped and doped. With these details in mind, we notice that the intensities of anti-Stokes Raman spectra presented in Figs 2 and 3 for the two excitation wavelengths (514 and 676 nm) are in good agreement with expectation.…”

“…Reproducible results were obtained using SERS supports of Au with average roughness of 100 nm, which had been prepared either by vacuum evaporation with an atomic beam at almost grazing incidence on a microscope slide used as target support, [36] or by an electrochemical oxidation-reduction cycle procedure of a Au plate. [37] For the two excitation wavelengths, we used a Jobin-Yvon T64000 Raman spectrophotometer, equipped with a CCD detector and a microprobe allowing the laser light to be focused on the sample within a spot of micrometer size. All Raman spectra presented in this paper have been corrected for the response of the detector over the investigated Raman range.…”

Improved surface‐enhanced Raman scattering of polypyrrole electrodeposited on roughened substrates composed of Au–Ag bimetallic nanoparticles

“…11 However, a more controllable and reproducible surface roughness can be generated through the control of the electrochemical oxidation-reduction cycle (ORC) procedures. 12,13 Much of the observed enhancement can be ascribed to the electromagnetic fields at the metal surfaces, 14,15 which is quite well understood. The remainder can be ascribed to the chemical enhancement 16,17 concerning charge transfer on the adsorbate-metal surface, which is poorly understood compared with electromagnetic enhancement.…”