Facile and solvent-free fabrication of PEG-based membranes with interpenetrating networks for CO2 separation

For nearly two decades, membranes derived from polyethers have served as promising candidate materials for CO2 separation. Due to the inherent tendency of high-molecular-weight poly(ethylene oxide) (PEO) to crystallize and thus reduce its CO2 permeability, prior studies have focused on membranes produced from low-molecular-weight poly(ethylene glycol) (PEG). In this work, a novel series of cross-linked PEG-based membranes composed of interpenetrating polymer networks has been generated through the use of amine-terminated Jeffamine and multiple acrylate-functionalized cross-linkers in a facile, solvent-free, two-stage reaction. Evidence of cross-linked interpenetrating polymer networks formed by aza-Michael addition and acrylate polymerization is confirmed by real-time fourier-transform infrared spectroscopy. In addition, we systematically investigate the thermal stability, mechanical properties and water sorption of these multicomponent membranes. Corresponding CO2 and N-2 transport properties, evaluated by single-gas permeation tests, are found to depend on both the chemical nature of the cross-linkers and the ratio of the interpenetrating networks. Moreover, free PEG dimethyl ether has been added into the optimized cross-linked matrix at different loading levels to further enhance gas-transport properties.