Fabrication of polyvinyl chloride ultrafiltration membranes with stable antifouling property by exploring the pore formation and surface modification capabilities of polyvinyl formal

• Polyvinyl chloride–polyvinyl formal blend ultrafiltration membranes were prepared.
• Polyvinyl formal played the dual roles of pore formation and surface modification.
• The water permeation flux of ultrafiltration membranes was considerably enhanced.
• Ultrafiltration membranes were rendered long-term stable antifouling property.

Polyvinyl chloride (PVC) and polyvinyl formal (PVF) blend ultrafiltration membranes were fabricated by non-solvent induced phase separation (NIPS) method with different casting solution composition. The PVC/PVF membranes were characterized and evaluated by scanning electron microscopy (SEM), Fourier Transform Infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), water contact angle measurement and performance measurement. The results showed that PVF played the role of pore formation agent during the NIPS process, and both of porosity and the mean pore size of the membranes were increased with the increased dosage of PVF. Simultaneously, PVF was enriched to membrane surface via spontaneous surface segregation and the membrane surface hydrophilicity was greatly elevated, which implied the remarkably enhanced antifouling property. The robust residence of PVF on the membrane surface was confirmed by a long-term test of incubating membranes in deionized water, which revealed the stable antifouling property of PVC/PVF membranes. Therefore, PVF could be explored as a potential versatile modifier for fabricating high performance ultrafiltration membranes.