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 N2 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.