Underwater superoleophobic poly(vinylidene fluoride)/poly(N-isopropylacrylamide) membranes for highly efficient oil-in-water emulsion separation

Superoleophobic and anti-oil adhesion behavior has been considered the central character of the materials for removing oil from wastewater. Herein, poly(vinylidene fluoride)/poly(N-isopropylacrylamide) (PVDF/PNIPAM) membranes were fabricated by vapor-induced phase separation (VIPS) and then further post-modified by deposition of sulfonated dopamine (SDA). The resulting membrane has a strong underwater superoleophobicity with an underwater toluene contact angle of 163 ± 2° and an ultralow adhesion force (1.9 ± 0.02 µN) between the surface and the oil. Therefore, it can efficiently remove emulsified toluene from water with a flux of 2211 ± 80 L m −2 h −1 bar −1 and an oil rejection of 99.5 ± 0.4%. This work offers a novel technique for the fabrication of porous membranes with excellent anti-oil fouling performance which will be practically used in the treatment of emulsified oils.