Breakthrough the upperbond of permeability vs. tensile strength of TIPS-prepared PVDF membranes

Permeability and mechanical strength normally present an opposite trend for separation membranes. There is a trade-off line of permeability vs. tensile strength for the prepared poly(vinylidene fluoride) (PVDF) membranes via thermally induced phase separation (TIPS) method. In this work, TIPS-prepared PVDF membranes were fabricated with water (PVDFT-water) and air (PVDFT-air) as quenching bath for comparatively studying. PVDFT-air membranes present larger average pore size, higher permeability and better mechanical strength than those of PVDFT-water membranes due to the lower cooling rate of air bath. It is wonderful that all PVDFT-air membranes can break though the trade-off line of permeability vs. tensile strength of TIPS-prepared PVDF membranes. The optimal membrane (M-A30) shows superior performance, such as ultrahigh water flux of 3275 L m−2 h−1·bar−1 and tensile strength of 5.7 MPa. Additionally, this research provides a feasible method to regulate the morphology, pore size and permeability of TIPS-prepared PVDF membranes.