New electrochemical procedure for elaborating homogeneous and strongly adherent PPy films on zinc electrodes

Electropolymerization of pyrrole on zinc was investigated in sodium tartrate aqueous solution in order to obtain homogeneous and adherent polypyrrole films. The tartrate counter-anions inhibit the working electrode dissolution by leading to the formation of a passivation layer on its surface. Consequently, homogeneous and strongly adherent polypyrrole coating has been successfully achieved with different electrochemical techniques, such as potentiodynamic, galvanostatic and potentiostatic modes. Polypyrrole coatings electrosynthesized on zinc electrodes have been characterized by several microscopic and spectroscopic techniques. Particularly, scanning electron microscopy (SEM) analysis has revealed a compact, homogeneous and thick polypyrrole film. X-ray photoelectron spectroscopy (XPS), IR and Raman analyses proved that the coatings obtained have globally the same structural features and elementary composition as those electrosynthesized on noble metals.