Barrier properties and structure of inorganic layers at polyaniline–steel interface

• Published in: Russian journal of applied chemistry Vol. 88; no. 7; pp. 1168 - 1173
• Main Authors: Smirnov, M. A., Sokolova, M. P., Dmitriev, I. Yu, Vlasova, E. N., Rozov, E. Yu, El’yashevich, G. K.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-07-2015
• Subjects: Applied Electrochemistry and Corrosion Protection of Metals; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Industrial Chemistry/Chemical Engineering; Barrier Layer; Anticorrosive Property; PANI; Barrier Property; Steel Surface
• ISSN: 1070-4272; 1608-3296
• DOI: 10.1134/S1070427215070101

Anticorrosive properties of inorganic layers formed on the surface of steel upon deposition of polyaniline doped with hydrochloric, sulfuric, or phosphoric acid were studied. It was found that the strongest anticorrosive protection is provided by the polymer containing chloride ions. An X-ray phase analysis demonstrated that the high packing order of chains of polyaniline doped with hydrochloric acid leads to formation of an inorganic barrier layer constituted by closely packed iron oxides and hydroxides. Application to the steel surface of polyaniline doped with sulfuric and phosphoric acids results in that barrier layers with weaker anticorrosive properties are formed. It is shown that, in the course of catalytic oxidation of iron by oxygen in the presence of polyaniline, there occur transitions between the emeraldine and pernigraniline forms of the polymer. IR spectroscopy confirmed that polyaniline doped with hydrochloric acid is the most active catalyst for steel surface oxidation.