Polysulfone-based amphiphilic polymer for hydrophilicity and fouling-resistant modification of polyethersulfone membranes

Polysulfone-based amphiphilic polymer polysulfone-graft-poly (ethylene glycol) methyl ether methacrylate (PSf-g-POEM) was synthesized and used to blend with polyethersulfone (PES) to tune the hydrophobicity and fouling-liable properties of PES membranes. Differential scanning calorimetry (DSC), contact angle measurements, X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM) were conducted to characterize the properties of blend membranes. DSC results showed that the blend samples were characterized with single Tg transition, indicating that the additives were compatible well with PES in membranes. Membranes hydrophilicity was evaluated by contact angle measurement and obviously enhanced wettability of blend membranes was found. XPS analysis suggested that poly (ethylene glycol) methyl ether methacrylate (POEM) brushes from amphiphilic additives occupied half part of the membrane surface composition, and the high content of POEM in surface had effectively improved the membranes hydrophilicity as well as the fouling-resistance to proteins. Meanwhile, the formation of cake layer was explored as a main reason for membrane fouling behavior, while the irreversible filtration resistance (Rir) could be greatly reduced by incorporation of the synthesized amphiphilic additives. SEM was also conducted to inspect the morphologies of blend membranes.