Chitosan-based self-healing protective coatings doped with cerium nitrate for corrosion protection of aluminum alloy 2024

• Published in: Progress in organic coatings 2012-09, Vol.75 (1-2), p.8-13
• Main Authors: Carneiro, J., Tedim, J., Fernandes, S.C.M., Freire, C.S.R., Silvestre, A.J.D., Gandini, A., Ferreira, M.G.S., Zheludkevich, M.L.
• Format: Article
• Language: English
• Subjects: AA2024; Aluminum base alloys; Cationic; Cerium (III); Chemical Sciences; Chitosan; Coatings; Corrosion prevention; Corrosion protection; Electrochemical impedance spectroscopy; Polymers; Protective coatings; Self-healing; Surface properties
• ISSN: 0300-9440; 1873-331X
• DOI: 10.1016/j.porgcoat.2012.02.012

► Fluorinated substituents of chitosan are suggested as protective films. ► Chitosan layer works as a reservoir for cationic Ce3+ corrosion inhibitor. ► Complexation of Ce3+ with chitosan amino groups prevents its uncontrollable and fast leaching. ► Ce-containing chitosan coatings were found to confer active corrosion protection toward aluminum alloy 2024. The good film forming ability, specific solubility and versatile chemical functionalization of chitosan make it a promising candidate for “green” protective coatings. In the present work, these features are exploited together with chitosan high complexing ability to obtain inhibitor-containing anticorrosion coatings for active protection of aluminum alloys. The functionalization of chitosan with fluorinated substituents was also evaluated as a possible route to improve barrier and surface properties of the coating matrix. It was observed that the chitosan layer worked as a reservoir for cationic Ce3+ corrosion inhibitor due to the complexation of Ce3+ with chitosan amino groups, which prevents its uncontrollable and fast leaching. These Ce-containing coatings were found to confer active corrosion protection toward aluminum alloy 2024 as shown by electrochemical impedance spectroscopy. Moreover, the corrosion tests evidence the self-healing ability of prepared chitosan-based “green” protective coatings. The interaction between Ce3+ and chitosan and the concentration effect of the former on the performance of the latter from a corrosion standpoint is also discussed.