Abstract: The flat-sheet ternary blend microporous membranes from poly(vinylidene fluoride-co-tetrafluoroethylene/dimethylsiloxane) were prepared by the phase inversion process. The membrane distillation process of 20g/L aqueous NaC1 solution was applied as a final test of membrane performance. The influence of PTFE content on the membrane structure and performance were studied by scanning electron microscope (SEM), contact Angle, membrane porosity and average pore size of membrane. The results showed the finger-like hole at cross-section of the blend microporous membrane was gradually replaced by a sponge-like structure with the increased of PTFE content. The mean pore radius from 0.234μm to 0.354μm and the porosity of prepared membranes varied from 53.4% to 81.3%; A contact angle of water droplet on the membrane bottom surface was increased from 118.52o to 131.11o; When the PTFE content was 40wt.%, the permeate flux and rejection were 16.60 kg/(m2h) and 99.99%, respectively. That was the rejection reached the maximum. Keywords: poly(dimethylsiloxane); poly(tetrafluoroethylene); poly(vinylidene fluoride); Hydrophobic microporous membrane; vacuum membrane distillation

Key words: poly(dimethylsiloxane), poly(tetrafluoroethylene), poly(vinylidene fluoride), vacuum membrane distillation