Electrochemical synthesis of poly(5-nitroindole) on 316L-stainless steel in LiClO4-acetonitrile solution and its corrosion performance

The preparation of poly(5-nitroindole) (P5NI) coating was achieved on 316L-stainless steel (SS). Poly(5-nitroindole) was deposited via anodic oxidation of the corresponding monomer in acetonitrile (ACN) solution containing LiClO4. The influence of P5NI coating against SS corrosion was studied in 3.5% NaCl solution by electrochemical impedance spectroscopy (EIS), anodic polarization curves and the open circuit potential–time (Eocp–t) diagrams. The results obtained suggest that P5NI coating forms a sacrificial layer but the efficiency against corrosion is limited with increasing time.