Preparation and characterization of poly(vinylidene fluoride) flat sheet membrane with Tg tunable amphiphilic terpolymer as membrane additive

• Tg tunable amphiphilic terpolymer was synthesized by free radical polymerization.
• The copolymer with a lower Tg has an easier surface segregation tendency.
• PVDF/copolymer blend membrane was prepared by NIPS process.
• P(MMA-BA-PEOM) is an efficient additive for PVDF membrane modification.

An amphiphilic terpolymer P(MMA-BA-PEOM) was synthesized by free radical polymerization and used as the macromolecular additive in the preparation of PVDF blend membranes. The glass transition temperature (Tg) of terpolymers was controlled with a wide range from − 6 to 40 °C by adjusting the feed ratio of rigid monomer MMA to soft monomer BA. The increase of static contact angle of copolymer with PBA content indicated that softer chain can facilitate the hydrophobic parts of the additive segregation to the surface of a polymer film at the solid–air interface. The observation of morphology of the extracted PVDF blend membrane verified that P(MMA-BA-PEOM) could facilitate the surface segregation. Filtration experiment showed that PVDF membrane modified by terpolymer P(MMA-BA-PEOM) has a higher pure water flux (365 L m− 2 h− 1) and relative flux recovery (71%) than that modified by bipolymer P(MMA-co-POEM).