Clay-based superamphiphobic coatings with low sliding angles for viscous liquids

Although significant attention has been paid, most of superamphiphobic surfaces suffer from high sliding angles (SA) for liquids with low surface tension and complicated preparation methods. Also, superamphiphobic coatings with high repellency to the liquids with very high viscosity and low surface tension are rare. Here, we report preparation of clay-based superamphiphobic coatings with low SAs for viscous liquids. A homogeneous suspension was prepared by hydrolytic condensation of 1H,1H,2H,2H-perfluorodecyltriethoxysilane and tetraethoxysilane in the existence of attapulgite, a kind of natural clay mineral with nanorods-like microstructure. The superamphiphobic coatings were readily prepared by spray-coating the suspension onto substrates. The effects of attapulgite on microstructure and superamphiphobicity of the coatings were studied. Also, the static and dynamic superamphiphobicity were investigated. The attapulgite concentration has great influences on superamphiphobicity and solid-liquid adhesion force of the coatings, as it determines microstructure of the coatings. The superamphiphobic surfaces feature high contact angles and low SAs for various liquids including those with extremely high viscosity and low surface tension, e.g., hydroxyl-terminated polybutadiene (HTPB) and the HTPB/Al mixture (1:1, w/w). The coating also shows low solid-liquid adhesion force, high impact resistance and fast rolling of various liquids.