Electropolymerization of pyrrole on zinc–lead–silver alloys electrodes in acidic and neutral organic media

Electropolymerization of pyrrole on zinc–lead–silver (Zn–Pb–Ag) alloys was carried out in acetonitrile, nitrobenzene and propylene carbonate (PC) organic media in the presence of para-toluene sulfonate counter ions. Adherent and homogeneous PPy films have been obtained on zinc alloy electrodes (65% Zn, 10% Pb and 25% Ag) prealably treated with aqueous sodium sulfide solution. Among the electrochemical techniques used in these experiments, the galvanostatic mode was proved to be better adapted to perform the electrosynthesis of polypyrrole using low applied current densities. The PPy coatings have been characterized by different microscopic and spectroscopic techniques. Scanning electron microscopy (SEM) showed that PC (DN=15.1) is the most suitable solvent for elaborating high-quality and thick PPy films. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) analysis proved that the obtained coatings have the same structure properties as those electrodeposited on noble Pt plates.