Ultrafiltration membranes based on hybrids of an amphiphilic graft copolymer and titanium isopropoxide

Graft copolymer poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) is combined with titanium isopropoxide (TTIP) to form hybrids that undergo phase separation in a water bath. The water permeance of the PVC-g-POEM membrane increases by hybridization with TTIP owing to an increase in the surface pore size and porosity. Upon heating to 80 °C, the water permeances of PVC-g-POEM and PVC-g-POEM/TTIP decrease owing to the increased thickness of the top layer. However, the bovine serum albumin (BSA) rejection of PVC-g-POEM increases, while that of PVC-g-POEM/TTIP decreases. This is attributed to accelerated dissolution of TTIP at 80 °C, resulting in a large number of surface pores. The antifouling performance is significantly improved by TTIP addition and heating owing to increased hydrophilicity, as confirmed by contact angle, O/C atomic ratio, and water content measurements. The PVC-g-POEM/TTIP membrane prepared at 25 °C shows the best performance [338 L m⁻² h⁻¹ bar⁻¹ (LMH) water permeance, 89.4% BSA rejection, and 91.9% flux ratio recovery].