A fluorine-free of polymer-ceramic superhydrophobic coating with combined characteristics of anti-corrosion, anti-icing, and hydrodynamic stability

Aluminum-lithium alloys are susceptibility to localized corrosion, stress corrosion cracking, and icing in harsh environments causing severe safety risks and life-cycle limitations. To address this, a robust, fluorine-free multifunctional ceramic-polymer composite coating is developed for simultaneous liquid repellence, corrosion protection, and anti-icing performance. The hierarchical polymer-ceramic microstructure traps air to form a solid-air-liquid triphasic interface, significantly enhancing long-term stability. This work integrates: (1) eco-friendly fluorine-free design using polyurethane-polydimethylsiloxane (PU-PDMS) matrix, (2) one-step air-spray fabrication enabling scalability, and (3) synergistic Al₂O₃-TiO₂/PU-PDMS composition achieving multifunctionality. Results demonstrate exceptional performances: static water contact angle of 165.9 ± 0.9°, sliding angle of 6.1 ± 0.5°, electrochemical impedance increment by 3 orders of magnitude, positive shift of corrosion potential by 90 mV with 99.2 % inhibition efficiency, significant delay of 229 % in the freezing time of seawater (210 s vs. 690 s), buoyancy enhanced by 33 %, drag reduction of 45.37 % validated via boat tests and COMSOL simulations, and certain air capture capability and resistance to water impact. Such coating provides a scalable, eco-conscious solution integrating corrosion resistance, icephobicity, drag reduction, and mechanical durability. The prepared coating is mainly applied to the surface structure of aircraft and ships (hull and bottom), which helps to reduce the corrosion and icing on the surface of aircraft and ships in low temperatures and high humidity environments, and reduces energy consumption during ship operation through drag reduction and buoyancy enhancement effects. Its multifunctionality stems from stable air-film formation, hierarchical roughness, and chemical passivation. This work provides a paradigm for sustainable polymer composite design, bridging interfacial engineering with industrial applications in aerospace and marine systems.