Effect of copolymer composition, temperature, and carbon dioxide fugacity on pure- and mixed-gas permeability in poly(ethylene glycol)-based materials: Free volume interpretation

Haiqing Lin, Benny D. Freeman, Sumod Kalakkunnath, Douglass S. Kalika

Research output: Contribution to journalArticlepeer-review

74 Scopus citations


Network copolymers, prepared by photopolymerizing poly(ethylene glycol) diacrylate (PEGDA: CH2{double bond, long}CHCOO(CH2CH2O)14OCCH{double bond, long}CH2) and poly(ethylene glycol) methyl ether acrylate (PEGMEA: CH2{double bond, long}CHCO(OCH2CH2)8OCH3), have been studied for mixed-gas CO2/H2 and CO2/CH4 separations. Gas separation properties in the networks are sensitive to copolymer composition, temperature, and carbon dioxide fugacity in the feed. In conventional approaches, the effect of temperature can be described by the Arrhenius equation, while the influence of copolymer composition and fugacity can only be described empirically; the corresponding models require a large number of adjustable parameters. However, as shown here, the three factors influencing gas transport correlate well with free volume, and a simplified free volume model with only two adjustable parameters can satisfactorily describe the effects of copolymer composition, temperature, and CO2 fugacity on pure- and mixed-gas transport properties. Copolymer composition and temperature can be directly related to the fractional free volume, while CO2 fugacity of the feed can be correlated with free volume via the glass transition temperature of the polymer-gas mixture, which is computed using Chow's model.

Original languageEnglish
Pages (from-to)131-139
Number of pages9
JournalJournal of Membrane Science
Issue number1-2
StatePublished - Mar 15 2007

Bibliographical note

Funding Information:
Activities at the University of Kentucky were supported by a grant from the Kentucky Science and Engineering Foundation as per Grant Agreement KSEF-148-502-05-130 with the Kentucky Science and Technology Corporation. We are also pleased to acknowledge support provided through a Kentucky Opportunity Fellowship administered by the University of Kentucky Graduate School (S.K.).

Funding Information:
We gratefully acknowledge partial support of this work by the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy (Grant No. DE-FG03-02ER15362). This research was also partially supported by the United States Department of Energy's National Energy Technology Laboratory under a subcontract from Research Triangle Institute through their Prime Contract No.: DE-AC26-99FT40675. This work was prepared with the partial support of the U.S. Department of Energy, under Award No. DE-FG26-01NT41280. However, any opinions, findings, conclusions, or recommendations expressed herein are those of the authors and do not necessarily reflect the views of the DOE. Partial support from the National Science Foundation under grant number CTS-0515425 is also acknowledged.


  • Carbon dioxide
  • Free volume
  • Membrane
  • Model
  • Poly(ethylene oxide)

ASJC Scopus subject areas

  • Biochemistry
  • General Materials Science
  • Physical and Theoretical Chemistry
  • Filtration and Separation


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