Eco-friendly and facile fabrication of polyimide mesh with underwater superoleophobicity for oil/water separation via polydopamine/starch hybrid decoration

Superhydrophilic and underwater superoleophobic polydopamine/starch@polyimide mesh (PDA/starch@PIM) was successfully fabricated by a facile, inexpensive and eco-friendly approach. The coating of PDA/starch hybrid on PIM resulted in good underwater superoleophobicity and superhydrophilicity. The formation of hybrid coating was characterized by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and atomic force microscope (AFM). The surface of PDA/starch@PIM exhibited special wettability with high oil contact angle (OCA) of about 153.8° underwater. Meanwhile, the decorated PIM showed superb durability towards various harsh conditions. In addition, the coated PIM exhibited excellent oil/water separation property and the separation efficiencies are higher than 99.5%. Even after 60 times of reuse, the coated PIM still maintained high separation efficiency. Because the proposed route is green, simple and cheap, the underwater superoleophobic PDA/starch@PIM has a wide application prospect in oil-polluted wastewater treatment.