A novel poly (ethylene glycol)-imidazolium-functionalized 6FDA-durene polyimides (PEG-Im-PIs) with various PEG chain lengths and PEG-IM contents have been developed as novel polymer membranes for high performance CO2-separation. The synthesis, characterization of these materials, together with the properties of the corresponding polymer membranes, including gas separation properties, will be discussed in detail.