Spray-driven assembly of micro/nano hierarchical structures in photocurable organosilicon/silica hybrid superhydrophobic coatings

Superhydrophobic coatings, known for their excellent water repellency, anti-fouling, and self-cleaning capabilities, are widely adopted in various fields. Due to environmental pollution and biosafety concerns associated with fluorinated materials, the design and development of safe, environmentally friendly, and cost-effective fluorine-free alternatives are significant. In this study, an accessible and cost-effective spray method is employed to create an organosilicon/silica hybrid superhydrophobic coating with a micro-nano hierarchical structure. The synergistic effects of solvent activation, solvent evaporation, and capillary action between nanoparticles facilitate the formation of a continuous, uniform micro-nano secondary rough structure. This structure forms through “migration-aggregation” and “peristaltic-migration” processes involving KH-570 modified nano-SiO 2 particles and organosilicon polyurethane acrylate (PSUA). The resulting micro-nano hierarchical rough surface, combined with low surface energy, endows the photocured coatings with excellent hydrophobicity (water contact angle of 151 ± 1.4° and water sliding angle of 6 ± 0.5°), along with anti-fouling and graffiti resistance. Additionally, the superhydrophobic coating has excellent weather resistance and adhesion, as well as acceptable wear resistance. This study provides proactive investigations into the induced formation mechanism of micro-nano secondary “mastoid” structures and the fabrication method for continuous and uniform superhydrophobic coatings, demonstrating significant potential application in textiles, marine vessels, and medical devices.