Électrosynthèse et analyse des propriétés physico chimiques d’un matériau composite: Polyaniline/TiO2

Abstract

In this work, we have prepared electrochemically and studied a composite materials obtained from an organic conducting polymer; polyaniline (PANI) and semiconductor; titanium dioxide (TiO2) particles. The (PANI+TiO2) composite material was deposited by cyclic voltamperometry (cycling) on electrodes of: platinum, oxidized titanium and indium tin oxide (ITO). It was characterized by cyclic voltamperometry and electrochemical impedance spectroscopy (EIS). The corrosion protection behavior of A304 steel protected by a composite material was also tested in an acidic medium. The influence of parameters such as concentration of aniline, concentration of TiO2 and pH of the solution were investigated. According to the electrode used nature, the cyclic voltamperogram showed one or more redox couples, which are characteristic of the oxidation and reduction states of the deposed composite material. The impedance spectroscopy study showed that the resistance of the film increases with the TiO2 content incorporated in the polymer, thereby confirming an improvement in the protection of the steel. The inhibitory effectiveness of the coatings was also justified when plotting Tafel curves, by a displacement of potential corrosion towards negative values. The SEM photos showed that (PANI+TiO2) composite was uniformly deposited on the substrate surface and the incorporation of TiO2 particles has been well confirmed by the EDX. After immersion into a corrosive solution for 45 min, no aggressive effect was observed and the coating films are still present. The I-V characteristics of PANI+TiO2 heterostructure diode showed non-linear nature of I-V curve of PANI+TiO2 heterostructure.