Gecko foot-inspired reduced graphene oxide surface with multi-resistant, nonpolar/polar separation and reliable adhesion utility

Nature offers intriguing examples for adhesive surface with superhydrophobicity, like gecko foot hair and red rose petals. The superhydrophobic adhesion surface mainly depends on its ingenious hierarchical structure and chemical composition. Utilizing biomimetic strategy, we synthesized a fluorosulfurized reduced graphene oxide powder with a hierarchical structure by post-processing of graphene oxide. The adhesive fluorine-sulfurized reduced graphene cotton (AFC) was successfully prepared by ultrasonic soaking, self-assembly and drying. The water contact angle of AFC was 154° ± 1.4°, and its maximum adhesion force was about 102.9 ± 4.9 μN. The AFC exhibited excellent high superhydrophobic adhesive because it possessed not only the C–F bond and microscopic morphology of wrinkles and protrusions but also the inherent roughness of cotton fabrics. Importantly, the high superhydrophobic adhesive properties of AFC were not attenuated by sonication for 200 mins or UV exposure for 30 hours. Interestingly, AFC had prominent oleophobic properties for certain organic solvents (e.g., glycerol, ethylene glycol, etc.) with surface tensions greater than 30 mN/m. Finally, AFC was successfully used to nonpolar/polar separation and transfer droplets to various accepted surfaces (e.g., copper sheets, stainless steel mesh, plastics, etc.), demonstrating its great potential in liquid mixture separation and microdroplet transport.