Omni-Directional Protected Nanofiber Membranes by Surface Segregation of PDMS-Terminated Triblock Copolymer for High-Efficiency Oil/Water Emulsion Separation.

An excellent antifouling membrane with high permeate flux is required for oil/water emulsion separation due to ever-increasing oily industrial wastewater. Thus, an intriguing integration of the Omni-directional protected porous membrane that combines a high porosity nanofiber membrane with a surface segregation mechanism is established for the first time. By applying polydimethylsiloxane(PDMS)-terminated triblock copolymer, the enrichment of the hydrophilic poly(ethylene oxide) (PEO) segment and the nonpolar PDMS segment on the surface of the nanofiber endowed the nanofiber membrane with underwater oleophobicity and low oil adhesion force, exhibiting oil resistance as well as oil release property. An ultrahigh permeate flux of ∼7115 L m-2 h-1 with a separation efficiency of ∼97.88% is achieved under the driving force of gravity (∼0.9 kPa), which is the highest permeate flux ever reported under similar conditions. Moreover, the surface segregation nanofiber membrane shows excellent reusability and ultrahigh permeate flux with the assistance of stirring in a long-term test, revealing the promising performances for the further particular application of oily wastewater.