Centrifugal Spinning of PVDF Micro/Nanofibrous Membrane for Oil–Water Separation

Poly(vinylidene fluoride) (PVDF) fibers have been widely investigated in the fields of electronics, filtration, and oil/water separation due to their exceptional piezoelectric/thermoelectric/ferroelectric properties, excellent chemical/thermal properties, and high mechanical properties. However, the application of PVDF micro/nanofibrous membrane in these fields is still limited due to the solvent toxicity of PVDF in the fiber preparation process. In this case, we developed an environmentally friendly strategy for producing pure PVDF micro/nanofibrous membranes. In detail, the centrifugally spun precursor PVDF/poly(ethylene oxide) (PEO) micro/nanofibrous membrane was obtained from a composite spinning solution composed of PVDF emulsion and PEO solution. Subsequently, the precursor micro/nanofibrous membranes were sintered at high temperature to decompose PEO and obtain pure PVDF micro/nanofibrous membrane. The results indicate that the pure PVDF fibrous membranes present nanostripe bumps on the surface. The height and number of nanostripe bumps can be easily controlled by the sintering temperature. Owing to the high surface roughness and low surface energy of the prepared PVDF fiber membranes, an excellent droplet rejection (above 155°) is produced. Moreover, PVDF micro/nanofibrous membranes have high flux (3837 L·m–2·h–1) and excellent water-in-oil separation efficiency (99.42%). This study describes a way to fabricate the pure PVDF micro/nanofibrous membranes and apply them to oil–water separation.