Solid-state NMR molecular dynamics characterization of a highly chlorine-resistant disulfonated poly(arylene ether sulfone) random copolymer blended with poly(ethylene glycol) oligomers for reverse osmosis applications.

We have investigated the dynamics-transport correlations of a chlorine-resistant polymeric system designed as a next-generation reverse osmosis (RO) membrane material by solid-state NMR spectroscopy. A random disulfonated poly(arylene ether sulfone) copolymer in the potassium salt (−SO3–K+) form (BPS-20K) was blended with poly(ethylene glycol)s (PEGs) for improving water permeability. Blended BPS-20K/PEG membranes maintained the intrinsic chlorine-resistant property of BPS-20K, with a somewhat reduced salt rejection. The dynamic characteristics of BPS-20K/PEG blends studied by the spin–lattice relaxation time (T1) and rotating frame spin–lattice relaxation time (T1ρ) indicated correlations with the observed water uptake and permeability. 1H T1 measured on the polymer’s aromatic phenylene rings and 1H T1ρ measured on the oxyethylene (−CH2CH2O−) units of PEG were sensitive to the morphological changes, due to the blending of PEGs, induced in the mixed matrices. Membranes made of BPS-20K/PEG blends, with a l...