Electrodeposition of polypyrrole on copper surfaces in OXA-DBSA mix electrolyte and their corrosion behaviour

Abstract

In this study, polypyrrole (PPy) coatings were formed on the surface of copper electrode via electrochemical polymerization method using different concentrations of monomer, oxalic acid (OXA) and dodecylbenzene sulfonic acid (DBSA) solutions. Prior to the coating process, a pre-passivation process was applied to the copper surface by cylic voltammetry technique in the presence of OXA. The passive copper surface is subsequently coated with PPy films bythe potantiostatic method. Corrosion behavior of uncoated copper and PPy coated copper electrodes after passivation were investigated by potentiodynamic polarization, chronoamperometry and impedance spectroscopy techniques in 0.1 M H2SO4. Characterization studies and surface analyses of the coatings were carried out by using Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG) and Scanning electron microscopy (SEM). The OXA-DBSA mix electrolyte significantly increased the surface homogeneity and adhesion of the coatings leading to a protection efficiency of approximately 100%. While all coatings protected the copper electrodeagainst corrosion, the coating with 0.1 M monomer, 0.1 M OXA and 0.1 M DBSA concentration provided the best protection.