A simple and effective approach to regulate and control pore structure of electrospun PTFE nanofiber membrane

Owing to its outstanding hydrophobicity, thermal stability, and chemical resistance, polytetrafluoroethylene (PTFE) has always been the ideal material in the field of membrane contactors. However, the pore structure regulation of the PTFE membrane is challenging due to its poor processability. Herein, a novel and simple strategy to adjust the pore structure of the electrospun PTFE nanofiber membrane was proposed by introducing sodium alginate (SA) into the PTFE/PVA spinning solution. The pore structure of the PTFE nanofiber membrane gradually changed from the nanofiber network to the "sea-island" structure with the increase of SA addition from 0 to 2.5 %, which brought about a decrease in membrane pore size from 1.49 to 0.58 μm. Meanwhile, with the increase of SA addition, there was an obvious improvement in the mechanical properties of obtained PTFE nanofiber membrane because of the higher packing density of PTFE/PVA/SA precursor nanofiber. Finally, the obtained PTFE nanofiber membrane was utilized in the membrane emulsification (ME) process, which exhibited excellent emulsion performance in terms of 0.30 μm average droplet size of Water-in-oil (W/O) emulsion (remaining stable for 30 days).