Superamphiphobic surfaces constructed by cross-linked hollow SiO2 spheres

By using stringed carbon spheres as template material, a series of hierarchical 3D cross-linked SiO2 coated carbon spheres and hollow SiO2 spheres were fabricated, and spray-coated on glass slides, followed by the fluorination treatment with per-fluorotrichlorosilane. The surface characterization and surface wettability data indicated that hollow SiO2 spheres spray-coated surfaces showed better superhydrophobicity and superoleophobcity properties than the corresponding solid C@SiO2 coated surface. This study further demonstrated that superamphiphobicity depends on two critical factors, namely a cavity- and spot-rich hierarchical structure and the size and shape of overhangs. Moreover, the optimal conditions for the preparation of hollow SiO2 coated glass slide were identified after a systematic investigation of various concentrations of the carbon precursor and tetraethylorthosilicate. It was found that when 0.10 g carbon spheres prepared from 1.0 M carbon precursor were used as the template and 20 mg/mL tetraethylorthosilicate was used as silica precursor, the hollow SiO2 coated glass slide exhibited the best superamphiphobic performance, with the highest contact angles and lowest sliding angles for various liquids, such as water, olive oil, n-hexadecane and n-dodecane. (C) 2016 Elsevier B.V. All rights reserved.