Triple-synergistic BNNSs@PDA/ODA/TiO₂-reinforced silicone-epoxy coatings with enhanced mechanical robustness and marine corrosion protection

Superhydrophobic nanofiller-modified organic coatings are widely used for metal corrosion protection but face critical bottlenecks: poor interfacial compatibility with resin matrices, insufficient hydrophobic durability under harsh conditions, and a trade-off between hydrophobicity and mechanical strength. To address these issues, this study developed a triple-synergistic modification strategy to synthesize a novel superhydrophobic filler (BNNSs@PDA/ODA/TiO₂) for reinforcing silicone epoxy (SE) coatings. Polydopamine (PDA) acts as a bionic bridge for multi-point anchoring, octadecylamine (ODA) forms a 3D hydrophobic network, and titanium dioxide (TiO₂) enables micropore filling and enhanced crosslinking. The BNNSs@PDA/ODA/TiO₂-SE composite coating exhibits significantly improved mechanical properties, including enhanced storage modulus, glass transition temperature, and crosslinking density, with interfacial chemical bonding being the dominant driver for performance enhancement. In simulated marine environments, the composite coating shows excellent long-term corrosion resistance, maintaining strong protective capability after prolonged immersion and effectively inhibiting corrosion at scratch sites. A coupled “diffusion-electrochemical reaction” model verifies that the superhydrophobic labyrinth effect and interfacial bonding synergistically inhibit corrosion mechanisms. This work provides a scalable design strategy for high-performance composite coatings integrating mechanical robustness and long-term corrosion protection, addressing the practical demand for durable coatings in harsh environments such as marine engineering and shipbuilding.