Electrochemical Deposition and Properties of Polyaniline Films on Carbon and Precious Metal Surfaces in Perchloric Acid/Acetonitrile

Beside the electrochemical polymerization of polyaniline (PANT) films on electrode surface, the medium of polymerization and the metal surfaces are essential to increase the yield and electrical conductivity of PANI formed. The electrochemical synthesis of films of PANI on pyrolitic graphite (PG), glassy carbon, gold and platinum electrodes in perchloric acid/acetonitrile solution (0.1 M HClO4/ACN) was investigated. Linear scan voltammograms (LSV) for these electrodes exhibited similar onset potentials (E-onset = 0.89 to 0.94 V) for the oxidation of aniline into its radical cation. The heterogeneous electron transfer constants at the onset potentials (k(et-onset)) varied as follows: Pt (7 x 10(-8) cm s(-1)) approximate to GC> Au > PG (0.6 x 10(-8) cm s(-1)). During multi-cyclic potentiodynamic electropolymerization processes, three pairs of anodic and two pairs of cathodic growth-peaks were observed for Pt, GC, Au, but three pairs cathodic growth-peak for PG. All electrodes present good stability vis-a-vis PANI. Outcomes of further studies on the resulting films, carried out with cyclic voltammetry (CV) are discussed and the resultant PANI thin films can be used as transducer in the construction of sensors platform.