Poly(ionic liquid)s as new materials for CO₂ absorption

Abstract

Abstract A series of imidazolium‐based ionic liquid monomers and their corresponding polymers (poly(ionic liquid)s) were synthesized, and their CO 2 sorption was studied. The poly(ionic liquid)s had enhanced CO 2 sorption capacities and fast sorption/desorption rates compared with room temperature ionic liquids. The effects of the chemical structures, including the types of anion, cation, and backbone of the poly(ionic liquid)s on their CO 2 sorption have been discussed. In contrast to room temperature ionic liquids, the polymer with PF anions had the highest CO 2 ‐sorption capacity, while those with BF or Tf 2 N − anions had the same capacities. The CO 2 sorption and desorption of the polymers were fast and reversible, and the sorption was selective over H 2 , N 2, and O 2 . The measured Henry's constants of P[VBBI][BF 4 ] and P[MABI][BF 4 ] were 26.0 bar and 37.7 bar, which were lower than those of similar room temperature ionic liquids. The preliminary study of the mechanism indicated that the CO 2 sorption of the polymer particles was more absorption (the bulk) but less adsorption (the surface). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5477–5489, 2005