Electropolymerization of Pyrrole and N-Methylpyrrole on Mild Steel Surface

Electrochemical polymerization of various ratios of pyrrole and N-methylpyrrole monomers were performed in aqueous toluene-4-sulphinic acid sodium salt (T4SNa) electrolyte, using galvanostatic method. The pH of electrolyte was adjusted by p-toluene sulphonic acid (PTSA). In order to prevent corrosion of mild steel substrates during coating deposition, all samples were pretreated in 0.5 M oxalic acid solution, employing galvanostatic method. This would passivate the steel substrate and facilitate the coating process as well. Corrosion resistance of coated substrates was investigated in 1 M NaCl solution using Tafel polarization technique. In addition, by using scanning electron microscopy (SEM), morphological characterization of coatings produced, was investigated. The ratio of 1 to 1 (pyrrole/N-methylpyrrole) could play an important role on corrosion properties of the resulting coated mild steel.