Self-assembled polymeric nanosheet-anchored nanofiber membrane for emulsion separation

High-performance water-oil separation materials are essential to reduce environmental pollution and improve resource utilization towards achieving carbon neutrality; however, most present separation materials are limited by the monotonous pore structure and uncontrollable interface, resulting in low separation efficiency and flux. Here, we develop a facile electrohydrodynamic strategy, based on the electrospray-sheeting technique, to create self-assembled polymeric nanosheet-anchored nanofiber membranes, for high-performance emulsion separation. By manipulating relative humidity to fabricate stem-like nanofibers and regulating their topological structure to control the resulting microelectric field, polymer-charged droplets are induced to deform and then innovatively assemble into leaf-like nanosheets anchored on the nanofibers, thereby constructing the membrane with hierarchical stem-leaf-like nanoarchitecture. The nanoarchitecture with superwettable pore channels enables the obtained membrane to simultaneously achieve striking separation efficiency (>99.32%) and flux (up to 4179 L m−2 h−1) for water-in-oil emulsions, all attributed to its supercapillary and demulsification-interception effects. This work may provide a distinctive platform for the development of advanced nanomaterials for filtration and purification. It is challenging to design membranes for oil-water separations due to unfavorable pore structures. Here, the authors use an electrohydrodynamic strategy, designing a membrane with a stem-leaf architecture to separate oil-water emulsions.