A flexible and transparent superhydrophobic coating on cotton fabrics with high mechanical and chemical stability for underwater insulation

Achieving both stretchability and excellent transparency of superhydrophobic surfaces simultaneously is a major challenge. We utilize three acrylic monomers 1H,1H,2H,2H-heptadecafluorodecyl acrylate, methyl methacrylate, 3-(trimethoxysilyl) propyl methacrylate to polymerize flexible, transparent, low surface energy random copolymers (PHMK) as the coating. The coating has excellent transparency (90.2 %) and the coated elastic cotton fabric exhibits superhydrophobicity (WCA = 160°) even at the tensile strain of 0–300 %. The water droplets on the surface can bounce repeatedly in a stretched state. The coating has excellent chemical and mechanical stability and maintains superhydrophobicity under various treatments such as in various organic solvents and HCl (pH = 1) immersion, 20 washing cycles, the Martindale abrasion test 1000 times, and the tape peeling test 600 times. In addition, the coated cotton fabric also has excellent underwater thermal insulation performance, which has great potential application in fields such as life jackets.