Development of Bio-Inspired Metallo-Supramolecular Polymers as Self-Healing Coatings for Corrosion Protection in Marine Environments

Marine infrastructure faces severe degradation due to chloride-induced corrosion, necessitating the development of durable, autonomously responsive protective coatings. Here, we report the synthesis and characterization of a bio-inspired metallo-supramolecular polymer network engineered via dynamic coordination between catechol-functionalized polydimethylsiloxane (Cat-PDMS) and transition metal cations (Zn²⁺ and Fe³⁺). Inspired by the adaptive adhesive chemistry of marine mussel byssus, this architecture integrates dynamic coordination bonds within a hydrophobic, low-surface-energy polymeric backbone to achieve rapid intrinsic self-healing and superior barrier properties. Spectroscopic analyses confirmed the reversible formation of mono-, bis-, and tris-catecholate metal complexes, which govern the viscoelastic and regenerative capabilities of the network. Scratch-closure tests demonstrated autonomous recovery of mechanical defects at ambient temperature without external stimuli within 12 hours. Electrochemical impedance spectroscopy (EIS) conducted in simulated seawater (3.5 wt% NaCl) revealed that the healed coatings restored their low-frequency impedance magnitude (|Z|_{0.01 Hz}) to over 10⁸ Ω·cm², exhibiting corrosion resistance comparable to the pristine state. This study bridges coordination chemistry, polymer engineering, and corrosion science, providing an effective paradigm for sustainable, high-performance protective coatings in aggressive marine environments.