Corrosion performance of polypyrrole-coated metals: A review of perspectives and recent advances

Abstract Corrosion is a big challenge in various fields that needs to be addressed, especially where metallic components are involved. In this regard, different types of materials have been used and studied to improve the anticorrosion properties of metallic substrates among which conducting polymers (CPs) have gained tremendous attention as anticorrosive coatings. This has opened a new research area for preparing cost-effective coatings with high performance. Among CPs, polypyrrole (PPy) is one of the most promising materials owing to its intrinsic anti-corrosion properties. Various protection mechanisms have been proposed for the PPy-coated metals and alloys, including ennobling or anodic passivation, cathodic protection, mediation of oxygen reduction, barrier protection, controlled inhibitor release mechanism, etc. In this paper, these mechanisms and the effect of different parameters (i.e. the substrate type, using co-polymerized PPy or its derivatives, and using nano-materials) are reviewed and discussed.