Ionic Polyimides: New Dimensions in the Design of Polymer Gas Separation Membranes

Ionic liquids (ILs) and polyimides (amond several other classes of materials) have been at the forefront of gas separation membrane materials in recent years. Although ILs and polyimides are seemingly disparate classes of materials, ILs and polyimides can be covalently attached via condensation polymerization reactions to form "ionic polyimides". Based on rational selection of precursors and reagents, there are 10,000's of feasible ionic polyimide structures along with the potential to incorporate elements from PIMs and TR polymers as well. We have already developed several unique ionic polyimide materials based on monomers formed from aminopropylimidazoles with PMDA, 6-FDA and other dianydrides. These diimide monomers are then reacted with dihalides through the imidazole moeities via SN2 reactions to form the ionic polyimides. Our first-generation ionic polyimides show excellent processability and display increased ordering in the presence of ILs. This presentation will discuss our design strategies, polymer characterization and performances as membranes in the separation of CO2, H2, N2 and CH4.