Facile modification of sepiolite and its application in superhydrophobic coatings

As one of nature clay minerals, sepiolite was used in various fields, such as photocatalytic, refractory, and dye adsorption, but rare in superhydrophobic application. In this study, sepiolite was modified by polysiloxane (Sepiolite@POS) and its microstructure, chemical composition, and hydrophobic property were investigated. Besides, its coatings were prepared by spray-coating the solution of Sepiolite@POS and epoxy (EP), which endowed various materials (wood blocks, steel sheets, A4 paper, and cotton) with excellent superhydrophobic property. In particular, as the mass ratio of Sepiolite@POS and EP was 7:5, the coating on glass slide presented a water contact angle above 160° and a sliding angle of 5°. And it could maintain superhydrophobicity after wear test or ultrasound treatment or immersion in solution with pH from 1 to 13, implying it had good mechanical and chemical stability. Besides, after being coated by Sepiolite@POS/EP, the surface possessed excellent self-cleaning property. Also, the Sepiolite@POS/EP coated melamine sponge could efficiently separate chloroform from water. All these results indicated that modified sepiolite showed great potential for application in the fields of waterproof, self-cleaning, and oil/water separation.