Superhydrophilic and mechanical robust PVDF nanofibrous membrane through facile interfacial Span 80 welding for excellent oil/water separation

We report a novel and facile welding strategy using Span 80 to simultaneously enhance the mechanical robustness and superhydrophilicity of an electrospun poly(vinylidene fluoride) (PVDF) nanofibrous membrane. By taking advantage of its amphiphilic property, Span 80 micelle is able to attach PVDF nanofibers due to the strong affinity between the hydrophobic segments of Span 80 and PVDF. The as-prepared PVDF nanofibrous membrane exhibited simultaneously improved stress (from 1.7 +/- 0.3 MPa to 8.8 +/- 0.6 MPa). Meanwhile, supherhy-drophilic property was endowed through the self-assembly of Span 80 on the hierarchical surface of PVDF membrane. Water contact angle (WCA) and under-water oil contact angle (UOCA) of the modified membrane was nearly 0 and 154.9 +/- 2 degrees, respectively. This membrane had a water permeability of 18,482.7 +/- 287.3 Lm(-2) h(-1)bar(-1) for 1, 2-dichloroethane-in-water emulsion with a separation efficiency of 96.3%. The welded PVDF nanofibrous membrane exhibited extraordinary robustness, resisting to long-term washing of water and oil-in-water emulsion.