Preparation of a sandwich-structured self-healing coating with antibacterial activity by incorporating inhibitor-loaded core-shell nanofibers into Ag-modified epoxy resin

Self-healing coatings have attracted considerable attention for metal protection. Specifically, the development of coating fabrication technologies that provide multiple functional properties can effectively mitigate the substantial economic and resource losses caused by corrosion. In this study, a novel sandwich-structured composite coating was realized by functionalizing different layers. The core-shell nanofibers interlayer embedded between two epoxy (EP) resin layers were prepared via coaxial electrospinning, with polyarylene ether nitrile (PEN) polymer serving as the shell, and benzotriazole/oleic acid (BTA/OA) encapsulated as the corrosion inhibitor within the core. Adhesion testing demonstrated that the fabricated composite coating exhibited strong adhesion between the layers as well as to the substrate, thereby satisfying the Grade 1 requirement. Owing to the well loading of BTA/OA inhibitors within the polymer shell and the efficient released through the microvascular network, electrochemical impedance spectroscopy results indicated that the impedance reached 6.31 × 10 5 Ω·cm 2 after 14 days of immersion in a 3.5% NaCl solution, indicating effective self-healing anti-corrosion performance. Additionally, the surface EP layer was modified through blending with and surface embedding of silver-based (Ag-based) glass antibacterial agents, achieved antibacterial efficacies exceeding 99% against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ). Overall, this study presents an efficient strategy for fabricating sandwich-structured anti-corrosion coatings that integrate self-healing capability and antibacterial activity, and robust structural stability, thereby demonstrating good potential for advanced metal protection applications.