ABA-triblock copolymer ion gels for CO 2 separation applications

Yuanyan Gu, Edward L. Cussler, Timothy P. Lodge

Research output: Contribution to journalArticle

48 Scopus citations


The gas separation performance of two block copolymer ion gel systems were examined for CO 2/N 2 and CO 2/CH 4 gas pairs. The ion gels were formed by self-assembly of 10-15wt% poly(styrene-b-ethylene oxide-b-styrene) (SOS) and poly(styrene-b-methyl methacrylate-b-styrene) (SMS) triblock copolymers in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMIM][TFSA]), via association of the insoluble S blocks. Due to the high ionic liquid (IL) concentration, these gels exhibit rapid gas transport properties as well as high selectivity. The selectivity for both gas pairs was influenced by the type of polymer midblock: the SOS gel shows higher selectivity than both pure IL and SMS gels. Gas solubility tests on [EMI][TFSA]/PEO solutions indicate that poly(ethylene oxide) can suppress the solubility of N 2 and CH 4, and thereby increase the selectivity for CO 2. This important result qualitatively agrees with the gel gas separation performance, and confirms the importance of the midblock chemistry. Additionally, since the selectivity mainly stems from the differential gas solubility rather than gas diffusivity, the real selectivities obtained from mixed gas experiments are almost the same as the ideal selectivities. Ion gels show favorable separation performance in comparison with the corresponding "upper bound" on the Robeson plots for CO 2/N 2 and CO 2/CH 4, highlighting the potential of these gels in future CO 2-selective membrane separation.

Original languageEnglish (US)
Pages (from-to)20-26
Number of pages7
JournalJournal of Membrane Science
StatePublished - Dec 15 2012


  • Block copolymer ion gels
  • CO separation
  • Ionic liquids
  • Membranes

Fingerprint Dive into the research topics of 'ABA-triblock copolymer ion gels for CO <sub>2</sub> separation applications'. Together they form a unique fingerprint.

  • Cite this