A novel colorful sepiolite-based superhydrophobic coating with excellent mechanical and chemical stability and self-cleaning property

Abstract Clay, which is a well-stocked mineral, has often been applied to colorful coatings. Sepiolite is a kind of clay that has excellent properties but has not being reported as a color paint. In this study, a colored paint composed of sepiolite, cationic dye, and organosilanes was sprayed with epoxy resin to form a colorful superhydrophobic coating. The low surface energy of organosilane and the micro-nano microstructure of the coating can form bubbles between the solid and liquid, endowing the coating with good water repellency and with a self-cleaning property. In addition, for aqueous solutions with pH ranging from 1 to 13, the contact angle (CA) of the coating remained greater than 150°. The chemical stability of the coating was very good and did not fade, even after immersion in 1 M NaOH or HCl solution for 24 h. The scratch test on the coating did not destroy the superhydrophobicity of the coating. Additionally, the coating had good mechanical durability, and its CA was still greater than 150° after 50 times of tape test.