Electropolymerized Polypyrrole Coatings Doped with Olive Leaf Extract for Corrosion and Biofouling Protection of Stainless Steel in Marine Environment

Abstract Biofouling and corrosion significantly impair the longevity and performance of marine infrastructure, leading to substantial economic and ecological costs. This study investigates the dual protective function of polypyrrole (PPy) coatings doped with olive leaf extract (OLE) on stainless steel (SS) substrates. The coatings were electrochemically synthesized via cyclic voltammetry and subjected to a seven‐day, in‐situ exposure in natural Mediterranean seawater. Surface characterization using scanning electron microscopy (SEM), atomic force microscopy (AFM), epifluorescence imaging, and crystal violet staining revealed a significant reduction in biofilm development on the OLE‐doped coatings. Furthermore, electrochemical impedance spectroscopy (EIS) and anodic polarization tests demonstrated a marked improvement in corrosion resistance. Among the formulations tested, SS/PPy‐LE 30 exhibited the most effective antifouling (ANFO) and anticorrosion (ANCO) properties. The incorporation of OLE, a bio‐based and nontoxic additive, substantially enhanced the structural integrity and functional performance of the PPy coatings. These findings indicate that OLE‐modified PPy films are promising sustainable alternatives to conventional toxic marine coatings. This study underscores the potential of green additives in advancing eco‐friendly surface engineering strategies for marine protection.