Fluorine-Free Nitrile Rubber-Based Superhydrophobic Coatings with Exceptional Stability, Self-Cleaning, and Anticorrosion Properties Enabled by a Scalable Bottom-Up Strategy

Nitrile rubber (NBR)-based superhydrophobic coatings hold significant potential for surface protection due to their elastomeric properties and ease of fabrication. However, achieving long-term chemical and mechanical stability remains challenging owing to the cross-linked structure of NBR and its poor interfacial compatibility with rigid inorganic nanoparticles. In this study, we reported a fluorine-free, durable superhydrophobic coating fabricated through olefin cross-metathesis-mediated covalent grafting of low-surface-energy octasilsesquioxane (POSS) onto NBR oligomers (dNBR-OVP). The fluidity of dNBR-OVP facilitates uniform deposition across diverse substrates, regardless of surface topography. Based on this bottom-up strategy, superhydrophobic coatings with water contact angles exceeding 150° were achieved, accompanied by a high silicon content of 33 wt % (at an optimal OVPOSS/NBR ratio of 1:1). The coatings demonstrate broad substrate compatibility at scalable production (iron, stainless steel, copper, glass, and wood), robust chemical stability under harsh conditions (pH 2–13, 3.5% NaCl), self-cleaning capability, exceptional mechanical endurance (withstanding 100 abrasion cycles), and impressive adhesion properties on various substrates (rating 4B for all tested samples in the ASTM D3359 test). Electrochemical impedance spectroscopy revealed that the impedance modulus (|Z|) at 0.01 Hz for coated iron remained 2 orders of magnitude higher than that of uncoated metal, even after harsh environmental exposure. This scalable, substrate-independent approach provides a viable pathway for designing high-performance superhydrophobic coatings for extreme industrial environments.