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Title: Ionic liquid compatibility in polyethylene oxide/siloxane ion gel membranes

Ion gel films were prepared by incorporating eight commercially available ionic liquids in two different cross-linked polymer matrices to evaluate their phase miscibility, gas permeability and ionic conductivity for potential applications as gas separation membranes and solid electrolyte materials. The ionic liquids cations were 1-ethyl-3-methylimidazolium, 1-ethyl-3-methylpyridinium, 1-butyl-1-methylpyrrolidinium, tributylmethylphosphonium, and butyltrimethylammonium with a common anion (bis(trifluoromethylsulfonyl)imide). In addition, ionic liquids with 1-ethyl-3-methylimidazolium cation with acetate, dicyanamide and tetrafluoroborate counterions were evaluated. The two polymers were cross-linked poly(ethylene oxide) and cross-linked poly(ethylene oxide)/siloxane copolymer. Differential scanning calorimetry, X-ray diffractometry and visual observations were performed to evaluate the ion gels’ miscibility, thermal stability and homogeneity. Ionic liquids with the least basic anion (bis(trifluoromethylsulfonyl)imide) and aromatic cations containing acidic proton (e.g. imidazolium and pyridinium) gave the most stable and miscible ion gels. Phase stability was shown to be a function of both ionic liquid content and temperature, with phase separation observed at elevated temperatures. In conclusion, gas permeability testing with carbon dioxide and nitrogen and ionic conductivity measurements confirmed that these ionic liquids increased the gas permeability and ionic conductivity of the polymers.
 [1] ;  [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2]
  1. National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); AECOM Corporation, Pittsburgh, PA (United States)
  2. National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0376-7388; PII: S0376738817316873
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Membrane Science
Additional Journal Information:
Journal Volume: 545; Journal Issue: C; Journal ID: ISSN 0376-7388
Research Org:
National Energy Technology Lab. (NETL), Pittsburgh, PA, and Morgantown, WV (United States)
Sponsoring Org:
Country of Publication:
United States
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Ion gel; Cross-linked poly(ethylene oxide); Carbon dioxide permeability; Gas separation membrane; Solid electrolyte
OSTI Identifier: