Taro leaf-inspired and superwettable nanonet-covered nanofibrous membranes for high-efficiency oil purification

Membranes with high permeance and low energy consumption are highly desirable for efficient oil/water emulsion separation. However, creating such materials still remains a great challenge. Here, we report a novel electrohydrodynamic assembly strategy to create a thin nanonet-covered skin with a taro leaf-like micro/nano hierarchical surface and submicron pores on a fibrous membrane. The resultant biomimetic composite membrane exhibits integrated properties of robust under-oil superwettability, low water adhesion, and high water intrusion pressure. Consequently, the membrane can effectively separate various surfactant-free and surfactant-stabilized emulsions under ultralow pressure (<10 kPa), with high permeation flux (maximum of 12 994 L m⁻² h⁻¹), excellent separation efficiency (water contents in filtrates below 50 ppm), and outstanding antifouling properties.