Significantly enhanced antifouling and separation capabilities of PVDF membrane by synergy of semi-interpenetrating polymer and TiO2 gel nanoparticles

Abstract PVDF membrane has strong hydrophobicity and low anti-pollution performance, greatly limiting its practical application. These drawbacks have been successfully overcome by designing and then preparing a membrane with a semi-interpenetrating polymer (semi-IPN) of PVDF/poly(acrylic acid) (PAA) as the membrane matrix, TiO2 nanoparticles as functional components and F127 as pore-forming agent. The semi-IPN was prepared by copolymerizing acrylic acid with N,N methyl acrylamide in the presence of PVDF, and the TiO2 gel nanoparticles were in situ formed in the membrane-forming process. The properties of the composite membrane were significantly affected by the semi-IPN, F127 and TiO2. By adjusting the membrane structure with the semi-IPN, F127 and TiO2 nanoparticles, we prepared a composite membrane with a water contact angle of 40o, a BSA rejection ratio of 87.5% and a water flux of 802.5 L/m2/h/bar. After a simple UV irradiation, the water flux of this composite membrane rose to 1030 L/m2/h/bar, without any rejection decline. The membrane contaminated by humic acid could recover the water flux up to above 95.3% of its original value by a single UV irradiation, showing a very good antifouling performance. In addition, the composite membrane also exhibited a very strong pollution resistance and separation performance for bovine serum albumin and oil-water emulsion. All in all, based on the synergy of the semi-IPN and the evenly dispersed TiO2 nanoparticles, the prepared composite membrane exhibited excellent comprehensive properties and demonstrated a great potential for various separation applications.