Improved antifouling properties of polyethersulfone membrane by blending the amphiphilic surface modifier with crosslinked hydrophobic segments

• Amphiphilic modifier with crosslinked hydrophobic segments was synthesized.
• The modifier was blended into polyethersulfone matrix to prepare membrane.
• Surface enrichment of the modifier improved membrane antifouling properties.
• The modifier can increase the pure water flux of membranes even at low addition.

In this study, a novel structured amphiphilic modifier with crosslinked hydrophobic segments was synthesized and used to fabricate antifouling membranes. The amphiphilic modifier (MF-g-PEGn) was synthesized by etherification of melamine formaldehyde (MF) prepolymer with polyethylene glycol (PEG), and blended in polyethersulfone (PES) matrix to prepare membranes via a nonsolvent induced phase separation method. The hydrophilic polyethylene oxide (PEO) segments in the modifier were enriched at membrane surface through spontaneous surface segregation, endowing membranes with improved antifouling properties. The hydrophobic MF segments in the modifier were entangled with PES chains for robust anchorage of PEO segments. Moreover, the presence of MF-g-PEGn reduced the thermodynamic stability of the casting solution, endowing the membranes with high porosity. The separation performance of membranes was evaluated using bovine serum albumin (BSA) aqueous solution as model system. During the filtration process, the flux recovery ratios (FRR) after BSA aqueous solution separation of the PES control membrane and PES/MF-g-PEG6000 (0.36 wt%) were 70.8% and 91.6% respectively. The pure water fluxes of membranes were improved from 60.7 L m−2 h−1 for the PES control membrane to 164.7 L m−2 h−1 for PES/MF-g-PEG6000 (0.36 wt%), and all the membranes possessed 100% rejection efficiency.