Ultrafine fibrous poly(tetrafluoroethylene) (PTFE) porous membranes (UFPPMs) were prepared by sintering
electrospun PTFE/poly(vinylalcohol) (PVA) composite membranes. Meanwhile, poly(acrylonitrile) (PAN)
nanofibers were co-electrospun to reinforcing the material. The effects of changing the PTFE/PVA mass ratio,
the sintering temperature and the heating rate on the structure and properties of the resulting membranes were
investigated. To observe the structure evolution of the ultrafine fibers during the sintering process, the prepared
UFPPMs were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM) and static
water contact angles (WCA). A unique interconnected fibrous network structure was formed. The spinning and
sintering conditions were optimized. Moreover, the UFPPMs exhibited a super-hydrophobicity and an excellent
lipophilicity. They also performed well in harsh water (saline feed solution 3.5 wt% NaCl and 10 wt% NaOH)
membrane distillation experiments. The permeate flux stabilized at 14.53 L m−2 h−1 and the salt rejection
remained above 99.8% after operating for 35 h.