Amphiphilic ABA copolymers used for surface modification of polysulfone membranes, Part 1: Molecular design, synthesis, and characterization

Two kinds of novel amphiphilic ABA copolymers, which are suitable for surface modification of polysulfone membranes, were successfully synthesized via the atom transfer radical polymerization (ATRP) technique, using a bromo-terminated difunctional polysulfone as macroinitiator. Firstly, the difunctional polysulfone macroinitiator was prepared by esterifying the phenolic end groups of polysulfone to α-haloesters. Secondly, the macroinitiator was used to initiate the polymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA) and 3-O-methacryloyl-1,2:5,6-di-O-isopropylidene-d-glucofuranose (MAIpG), resulting in two kinds of ABA copolymers, i.e., P(PEGMA)-b-PSF-b-P(PEGMA) and PMAIpG-b-PSF-b-PMAIpG, respectively. In the case of PMAIpG-b-PSF-b-PMAIpG, the isopropylidenyl groups of the protected sugar residues were removed by acidolysis treatment, thus the amphiphilic ABA copolymer, PMAG-b-PSF-b-PMAG, was obtained. The resultant copolymers were characterized by FT-IR, 1H NMR, GPC, and TGA. Semipermeable polysulfone membranes prepared via the standard immersion precipitation phase inversion process, using the synthesized amphiphilic ABA copolymers as additives, display enhanced hydrophilicity and protein resistance compared to unmodified polysulfone membranes.