Design of fluorine-free superhydrophobic silk fabrics with mechanical durability and self-cleaning properties for oil-water separation

The separation of oil and water can be effectively addressed through the application of superhydrophobic coatings. This method, known for enhancing the self-cleaning, anti-corrosive, and friction-reducing properties of materials, typically employs fluorine reagents to ensure the durability of the coating nanostructure. However, the use of fluorine reagents raises concerns related to health and the environment. We present a straightforward and efficient approach to fabricate a robust, fluorine-free superhydrophobic composite coating. The coating solution, comprised of hydrophobic silica nanoparticles and polydimethylsiloxane (PDMS), is formed through sonication. The resulting superhydrophobic coating is effortlessly applied to silk fabric through immersion and subsequent drying/curing. micrograph confirms the creation of porous micro/nanostructures on the silk fabric's surface. Exceptional superhydrophobicity is demonstrated with a water contact angle (WCA) of 161 degrees +/- 1.5 degrees and a small sliding angle (SA) of 5 degrees +/- 0.5 degrees. The coating's firmness, durability, and UV resistance are assessed through 20 cycles of sandpaper friction (load 200 g) and repeated tape peeling tests. Furthermore, the modified silk fabrics exhibit excellent capabilities in oil-water separation. This fluorine-free superhydrophobic coating, characterized by its robustness, environmental friendliness, and ease of manufacture, holds promising applications in the textile industry.