Durable Superhydrophobic Surfaces Prepared by Spray Coating of Polymerized Organosilane/Attapulgite Nanocomposites

Complicated and expensive preparation methods and the low stability of most superhydrophobic surfaces are the bottlenecks that must be faced for their practical application. Herein, a simple and low-cost approach for preparing durable superhydrophobic surfaces by spray coating of polymerized organosilane/attapulgite (POS/APT) nanocomposites is reported. The POS/APT nanocomposites were prepared by condensation of hexadecyltriethoxysilane and tetraethoxysilane in the presence of APT through a modified Stöber method. The morphology and content of clay minerals have great influence on the superhydrophobicity. Only rodlike APT with a weight ratio of APT to organosilanes not less than 0.60 can form the superhydrophobic surfaces. The POS/APT superhydrophobic surfaces feature high water contact angle (CA≈160°), low sliding angle (SA≈2°), excellent stability, and good transparency. A spray coating density as low as 5 g m^-2 is enough to obtain the superhydrophobic properties. The cost of such a coating is approximately 4 RMB m^-2 . The POS/APT surfaces are stable towards sand abrasion, water pressure, harsh temperature, UV irradiation, and solvent immersion. In addition, a slightly damaged surface can be readily repaired by spray coating again according to the same procedure. Moreover, the durable POS/APT superhydrophobic coatings are applicable to various substrates (e.g., polyurethane plate, paper, and polyester textile) and can be easily scaled up.