Corrosion Inhibition and Antifouling Performance of Epoxy Coating Functionalized with PEDOT: PSS-Cerium Doped Zinc Oxide Hybrid Composites

Abstract

Abstract Steel corrosion and biofouling have adverse impacts on various high-end engineering applications including, in biomedical and maritime industries. Smart functional polymer coatings have been developed to simultaneously control corrosion and prevent biofouling problems on steels. In this study, translucent epoxy coatings loaded with 1, 3, and 5 wt% of functional hybrid composite (HC) microparticles were formulated. The HC particles contained cerium doped ZnO encapsulated in conductive poly(3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT: PSS) polymer at mixing ratio of 3:1. The effects of HC composition towards the corrosion inhibition and antifouling properties of the coating were evaluated. The microstructure and composition analyses were performed by using SEM and EDX techniques. The anticorrosion performance of the coating films deposited on stainless steel (SS 316 L) substrates was evaluated by using the Potentiodynamic Polarization (PP) technique. The antifouling characteristics of the coatings were investigated by performing the antimicrobial susceptibility test and a series of photodegradation test in medium containing ∼108 CFU/ml of bacteria under UV light in 180 minutes. The findings revealed that the presence of PEDOT:PSS-Ce doped ZnO HC increased the barrier properties of the epoxy matrix on SS 316 L against corrosion. The corrosion inhibition properties increased with increasing HC composition. The formulated coatings also exhibited antifouling effects against bacteria. The Gram positive-S. aureus exhibited susceptibility against the coating whereas the Gram negative – S. aureus showed resistant. The coatings demonstrated photocatalytic properties under UV light irradiation and capable of inactivating <99% of bacteria in less than 180 min. The epoxy coating functionalized with 5wt% HC exhibited the highest corrosion inhibition performance (corrosion rate of 0.0001 mm/year) and excellent antifouling effects against selected bacteria.