Microstructure manipulation in PVDF/styrene-maleic anhydride copolymer composite membranes: Effects of miscibility on the phase separation

Amphiphilic copolymers have increasingly attracted researchers? attention to produce the hydrophilic and antifouling polymeric membranes. However, few studies has been reported on systematic manipulation of matrix miscibility to control the membrane microstructure during the nonsolvent induced phase separation (NIPS). Herein, a facile method is brought forward to investigate the effects of miscibility on the structure and performance of the membranes. Through the transformation of styrene-maleic anhydride copolymer (SMA) into sodium styrene-maleic anhydride copolymer (SMANa), a homogeneous and transparent dope solution was successfully prepared. Next, the crescent pores and spherical particles in the PVDF/SMA membrane were eliminated to achieve the uniformly porous PVDF/SMANa membranes by the exchange of nonsolvent and solvent components. Importantly, SMANa could segregate at the external surface and internal pore walls as SMA to enhance the hydrophilicity and antifouling properties of the membranes. Subsequently, by optimizing the dope solution composition and coagulation bath temperature, PVDF/SMANa ultrafiltration membranes exhibited the pure water flux of 10(14) L/m(2)h and the rejection to BSA of 98.9%. These results outperformed previously reported ones for similar PVDF composite membranes. Significantly, this strategy can be applied to the large-scale manufacture of membranes.

Automated summary

The study investigates the effects of matrix miscibility on membrane microstructure during NIPS process, leading to the development of PVDF/SMANa ultrafiltration membranes with superior performance. This strategy holds promise for large-scale membrane manufacturing.