A Fluorine-Free Multifunctional Superhydrophobic Coating with Synergistic Photoelectrothermal Anti-/De-Icing and Antibacterial Properties for Marine Protection

Icing critically compromises the safety and operational stability of marine equipment and shipboard devices in winter or polar regions, while marine biofouling accelerates material corrosion. Therefore, coating technologies are urgently required to synergistically integrate efficient anti/deicing with robust antibacterial and anticorrosion properties. Herein, we develop a fluorine-free multifunctional coating based on hydrophobically modified SiO2@Ag/few-layer graphene powders. It is fabricated via a multistep process involving encapsulation of silver nanoparticles within a silica shell, compounding with few-layer graphene, surface modification with hexadecyltrimethoxysilane, and incorporation into an epoxy resin matrix. It exhibits a water contact angle of 152° ± 2° and a sliding angle of 1.5° ± 1°. Under 1 Sun illumination, its surface temperature reaches a maximum of 83.1 °C and remains stable over ten on/off cycles, and electrothermal heating at 20 V raises its surface temperature to 107 °C. It delays frost formation by a factor of 3.6 relative to the bare substrate and maintains a consistently low ice adhesion strength of ∼13 kPa even after multiple freeze-thaw cycles. Upon synergistic photoelectrothermal effect, defrosting is completed within 60 s, and a 1 cm-thick ice layer is melted in 487 s. It displays bactericidal rates of 99.41% against Vibrio natriegens and 98.59% against Bacillus subtilis, and demonstrates favorable biocompatibility in marine environments. Furthermore, it retains its hydrophobicity after mechanical abrasion, chemical exposure, UV aging, and corrosion resistance testing. From a practical perspective, this coating can be applied to diverse substrates and entails a reasonable fabrication cost. Therefore, this study demonstrates an efficient solution to integrating robust anti/deicing and antibacterial functions for protecting equipment in harsh environments.