Corrosion of conductive polypyrrole: Effects of continuous cathodic and anodic polarisation

The effects of continuous cathodic and anodic polarisation on the corrosion of polypyrrole (PPy) films were investigated in neutral 0.1 M NaCl with various electrochemical methods and spectroscopic analyses. With continuous cathodic polarisation, the PPy film nearly maintains the conjugated structure of PPy chains, but loses its electroactivity slightly. With increases in anodic polarisation potential and polarisation time, the electroactivity loss of the polarised PPy film increases rapidly especially at a higher anodic potential; while the damage to the conjugated structure of PPy chains also becomes severer with increasing polarisation time. The mechanisms involved were discussed.

► PPy films nearly keep the conjugated structure after cathodic polarisation.
► PPy films slightly lose their electroactivity after cathodic polarisation.
► PPy films lose more electroactivity with increases in anodic potential and time.
► Cl− attacks PPy to break the conjugated structure at an anodic potential.