Design and construction of PTFE porous membranes with high modulus and structural stability via in-situ interlocking and anchoring strategy

PTFE nanofiber membrane, as an effective supplement to biaxial stretched PTFE membrane, suffers from low modulus and poor structural stability. In this study, the PTFE porous membrane with high modulus and structural stability was designed and achieved via the in-situ interlocking and anchoring strategy by co-electrospinning polyacrylonitrile (PAN) into PTFE matrix. During the sintering process, the continuous flexible PTFE nanofibers formed, while PAN nanofibers was pre-oxidized to create a stable trapezoidal structure. The effects of pre-oxidized PAN (OPAN) nanofibers' content and diameter on the morphology and structure of the PTFE/OPAN composite nanofiber membrane were investigated in detail. Results showed that the introduction of OPAN nanofiber effectively improve the modulus and structural stability of PTFE nanofiber membrane. The Young's modulus and tensile strength of the composite nanofiber membrane were over 50 MPa and 2 MPa, which were 1166% and 80% higher than that of pure PTFE nanofiber membrane, respectively. These results of this work would contribute to solve the defects of PTFE nanofiber membrane's low modulus and poor structural stability, and then expand its application scope.