Comparison study between corrosion protection of polypyrrole synthesized on stainless steel from phthalate and saccharinate aqueous medium

Polypyrrole (PPy) was deposited on 304 stainless steel (SS) surfaces from aqueous solutions of sodium phthalate and sodium saccharinate, by electrochemical methods including cyclic voltammetry, chronopotentiometry and chronoamperometry. The anticorrosive properties of PPy coating doped with phthalate ions were studied by various techniques of analysis such as (XPS, SEM, SIE and OCP), and compared to those of PPy doped by saccharinate. The coating doped with phthalate ions showed the same structural characteristics obtained in the case of films synthesized in a saccharinate medium. In addition, these coatings have shown good protection against corrosion of stainless steel in saline medium (3% NaCl). The polypyrrole film has a dual behavior as an energy barrier against the penetration of aggressive ions (Cl−) and as an oxygen reduction catalyst.