Novel dual superlyophobic materials in water-oil systems: under oil magneto-fluid transportation and oil-water separation

Materials with superhydrophobicity under oil or superoleophobicity underwater have attracted great attention due to their widespread applications in non-loss liquid transportation and oil-water separation. However, it is a big challenge to prepare dual superlyophobic materials in oil-water systems (simultaneously superhydrophobic under oil and superoleophobic underwater) due to the thermodynamic unfavorable state of dual superlyophobicity. In this work, we fabricated dual superlyophobic polyimide films and a stainless steel mesh using a simple one-step approach. They can maintain their superlyophobicity in hexane-water, petroleum ether-water and dichloromethane-water systems, even if after oil immersion for 2 h, or without additional surface modifications when the oil-water systemis changed. The dual superlyophobic polyimide film can be utilized as a non-loss magneto-liquid transportation under oil, and dual superlyophobic stainless steel mesh can be used to separate hexane-water, petroleum ether-water and dichloromethane-water mixtures with separation efficiencies greater than 99.90%.