Improved hydrophilicity and antifouling performances of PVDF ultrafiltration membrane via in situ cross-linking

A novel polyvinyl alcohol (PVA) and β-cyclodextrin (β-CD) cross-linked polyvinylidene fluoride (PVDF) (PVA-β-CD/PVDF) ultrafiltration membrane was prepared via in situ cross-linking in combination with non-solvent induced phase separation. Compared with PVDF/PVA blending membrane, cross-linking solved the issue of interface pores on the membrane surface caused by poor compatibility. And obvious cross-linking polymers were observed inside the membrane, which introduced more hydrophilic hydroxyl groups and thus enhanced the overall hydrophilicity of the membrane. When the PVA/β-CD ratio was 1:2, the cross-linked membrane exhibited better hydrophilicity, the dynamic water contact angle decreased from 74.6° to less than 2.5° in 65s, and the maximum pure water flux of 4561.5 L m −2  h −1  bar −1 (about 11 times that of PVDF membrane), BSA rejection ratio of 96.7% and a flux recovery rate of 93.5% were obtained. The mean pore size was 0.064 μm, and porosity was 78.44%. It could be concluded that in situ cross-linking simultaneously improved the penetration, separation and antifouling performances of the modified membranes. Our work provides some insights into fabricating high permeable and antifouling PVDF ultrafiltration membranes. Graphical abstract