Mussel-inspired superhydrophobic coating via self-assembled polydopamine/SiO2 for enhancing the durability of marine concrete

Superhydrophobic coatings offer significant potentials for extending the service life of marine concrete infrastructure by mitigating water-driven deterioration. However, the widespread adoption in marine settings is hampered by inadequate chemical robustness, environmental concerns, and complicated manufacturing routes. Drawing inspiration from the strong underwater adhesion of marine mussels, we report a simple and scalable strategy for producing a robust superhydrophobic coating directly on concrete surfaces. The process relies on the spontaneous self-assembly of polydopamine@SiO2 core-shell nanospheres, which construct a hierarchical roughness, followed by grafting with 1 H, 1 H, 2 H, 2H-perfluorodecanethiol (PFDT) to lower the surface energy. The optimized formulation— 3 P@1.0NS-5PFDT (PDA:SiO2 = 3:1, 1.0 mg mL⁻¹ nanospheres, 5 mM PFDT)—achieves a water contact angle of 154.5°±1.5° and maintains near-zero water permeability for 120 h. Characterization confirms uniform nanospheres incorporation and successful PFDT functionalization. Compared to uncoated concrete, the coating reduces carbonation depth by > 70 %, suppresses ice accretion by 99 %, and lowers steel corrosion mass loss by 87.5 %. It retains performance after salt spray, wet-dry cycling, thermal cycling, and UV irradiation, though mechanical abrasion resistance requires improvement. Requiring no specialized equipment, this mussel-inspired approach offers a scalable and effective route to enhance the durability of concrete in demanding marine environments.