Recycled Superwetting Nanostructured Copper Mesh Film: Toward Bidirectional Separation of Emulsified Oil/Water Mixtures

Recently, superwetting films for separating oil/water emulsions have gained much interest due to their remarkable advantages such as high efficiency and high flux. Until now, although a lot of superhydrophobic/superoleophilic and superhydrophilic/underwater superoleophobic films have been prepared for separation of water-in-oil and oil-in-water emulsions, respectively, smart films that can separate both the types of emulsions are still rare, especially a general rule in designing such a smart bidirectional separating film is still a challenge. Herein, a new design strategy is advanced and a novel smart nanostructured copper mesh film is reported, on which both the water-in-oil and oil-in-water emulsions can be separated with high efficiency and high flux. The special separating ability can be ascribed to the combined effect of nanoscale pores on the film and the tunable wettabilities, which can switch reversibly between the superhydrophobic/superoleophilic and superhydrophilic/underwater superoleophobic states. This paper reports a smart recycled separating film for oil/water emulsions and displays particular bidirectional separating performances. The reported design concept is so simple that can easily be extended to many other smart materials and can open up some new perspectives for the fabrication of novel oil/water separating materials.