PEG–imidazolium-functionalized 6FDA–durene polyimide as a novel polymeric membrane for enhanced CO2 separation

A series of poly(ethylene glycol)–imidazolium-functionalized 6FDA–durene polyimides (PEG–Im-PIs) with a range of PEG chain lengths was developed. The structures and properties of this series, as well as the gas separation properties of the corresponding polymer membranes, were studied. A PEG group and an imidazolium-based ionic group, both of which acted as CO2-solubilizing groups, were incorporated onto a rigid polyimide backbone to yield a very high CO2 solubility and, hence, excellent CO2/CH4 (49.2) and CO2/N2 (40.1) permselectivities while maintaining a good permeability of polyimide.