Preparation and study of stable fluorine-free superhydrophobicity of cotton fibers

This paper proposes a method of directly modifying the surface of cotton fiber to achieve super-hydrophobic properties. The process was directly utilized the long-chain alkyl siloxane and the nano-SiO₂ modified cotton cloth, which was simple to operate, low in cost and environmentally friendly. This study discussed the influence of solvent ratio, reactant content and ammonia content on hydrophobicity. The solvent ratio had the greatest influence, and the maximum water contact angle (CA) changes were70° ± 1°. The maximum water CA of the superhydrophobic cotton fabric prepared after process selection was 162 ± 1.5°; it had good acid, alkali and salt resistance. After 24 h in a solution with a pH of 1–14, CA remained almost unchanged; After 144 h in a 3.5% salt solution, CA stabilized above 132°; it had self-cleaning properties; it had good selective adsorption performance, which can quickly separate oil and water; it had good mechanical stability. After 300 times abrasion of sandpaper, which still shows hydrophobic properties.