Additive-free poly (vinylidene fluoride) aerogel for oil/water separation and rapid oil absorption

Highly porous poly (vinylidene fluoride) (PVDF) aerogel that is superhydrophobic and superoleophilic was successfully prepared through vapor induced phase inversion process. The unique hierarchical micro-nano structures are studied by scanning electron microscopy and Brunauer–Emmett–Teller surface area analysis. The PVDF aerogel is superhydrophobic, with a water contact angle of 151°, and can almost instantaneously absorb oil. Contributed by the hierarchical micro-nano structure, both surfactant-free and surfactant-stabilized water-in-oil emulsion can be effectively separated by the fabricated PVDF aerogel simply under gravity; with good flux and high filtrate purity up to 99.99%. PVDF aerogel also exhibits moderate oil absorption capacity of 3–7g/g and high up-taking rate for various types of oil. Furthermore, we found that PVDF aerogel is highly stable against concentrated alkaline solution owing to its superhydrophobicity. We further investigated the reusability in oil/water separation and oil absorption, as well as the mechanical properties of PVDF aerogel. As a non-crosslinked thermoplastic polymer, PVDF aerogel can be easily recycled, reused and reformed into any shape. This type of aerogel has potential to be used for environmental applications including oil spillage cleanup and oil purification.