Anilinium 5-sulfosalicylate electropolymerization on mild steel from an aqueous solution of sodium 5-sulfosalicylate/disodium 5-sulfosalicylate

Aniline is electropolymerized on bare and chemically pretreated mild steel from an aqueous solution of 0.10 M anilinium 5-sulfosalicylate in 0.20 M sodium 5-sulfosalicylate/0.20 M disodium 5-sulfosalicylate buffer as the supporting electrolyte, at room temperature. At constant anodic potential black poly(anilinium 5-sulfosalicylate) (PANISSA) films are obtained on bare mild steel and characterized by IR spectroscopy, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). IR spectroscopic analysis confirms typical polyaniline structure with 1,4-disubstituted aromatic nuclei and incorporation of sulfosalicylate anions as dopants. Adhesion of PANISSA films is significantly improved when the mild steel electrode surface is chemically pretreated by 0.10 M ammonium peroxydisulfate aqueous solution. The HZ spectra of the films obtained on chemically pretreated mild steel surface indicate an interaction between PANISSA and products of the mild steel oxidation by peroxydisulfate. The SEM images show differences in morphology between PANISSA films synthesized on bare and chemically pretreated mild steel surface. The efficient anticorrosion behavior of adherent PANISSA film on chemically pretreated mild steel is proved by EIS.