pH-Responsive Nanostructured Polyaniline Capsules for Self-Healing Corrosion Protection: The Influence of Capsule Concentration

Abstract

Abstract. Nanostructured hollow polyaniline (PANI) capsules are good candidates for encapsulation of corrosion inhibitors and pH-responsive release when incorporated into organic coatings. In previous studies, the corrosion protection performance of PANI capsules, containing organic inhibitor 2-Mercaptobenzothiazole (MBT), was demonstrated. The present work studies the in uence of capsule concentrations (i.e., 0.3, 1, and 2 wt%) on the corrosion protection properties of the coating system. Anti-corrosion properties of di erent coatings were compared by means of Electrochemical Impedance Spectroscopy (EIS) and Scanning Vibrating Electrode Technique (SVET). MBT loaded PANI capsules in epoxy ester coating on AA2024-T3 substrate allow for a self-healing e ect to be obtained during the corrosion process. The results showed that the concentration of MBT loaded PANI capsules greatly in uences the corrosion protection properties of the coatings, and the best corrosion protection performance was observed for the coating system containing 1 wt% PANI capsules. The impedance value of the scratched area of this coating after 7 days of immersion was one order of magnitude higher than that of the control sample.

Synthesis and characterization of polyaniline–hydrotalcite–graphene oxide composite and application in polyurethane coating

“…The presence of PAN in the structure of the composite PAN-HG helps to enhance the protection on the CT3 steel surface due to the complicated protection mechanism of PAN. Those mechanisms are anodic protection, [45][46][47][48][49][50] cathodic protection, [50][51][52][53] controlled inhibitor release, [54][55][56] and barrier protection. 72 From the results of corrosion protection, both 1PAN-HG and 2PAN-HG have the same corrosion protection.…”

“…Then, the combination of the Fe cation and reduced PAN can give a passively complex layer to prevent the penetration of ions. Moreover, PAN was studied to fabricate a composite with either organic compounds, such as sulfonated chitosan, 52 2-mercaptobenzothiazole, 53 benzoate, 69 nylon 66, 54 and palm oil; 55 or inorganic clays, such as magnetite clay, aluminium oxide and gamma-alumina. 24,34,56 All of those studies show that composites from PAN give good anti-corrosion performance in both HCl and NaCl environments.…”