Theory of the Structure of lonomeric Membranes

  • Anton J. Hopfinger
  • Kenneth A. Mauritz
Part of the Comprehensive Treatise of Electrochemistry book series (volume 2)


Ionomers are two-phase materials which show considerable promise as ion-selective membranes. Nafion,† in particular, is being used on a limited commercial basis in chloralkali separation processes. Its chemical structure, shown in Figure 1, is typical of ionomers. Pendant side chains, each containing an ionizable group, are essentially spaced uniformly along a linear chain composed of relatively nonpolar groups. The number of nonpolar units is far greater than the number of polar-ionizable groups. This leads to the particular two-phase structure. Polar groups self-associate to form hydrophilic clusters in a sea of nonpolar material. In general, ionomeric structure has been studied by X-ray diffraction, dielectric and mechanical spectroscopies, and by electron microscopy.(1–3) The polar clusters of Nafion have also been investigated by infrared(4) and NMR(5) spectroscopies. Figure 2 shows a transmission electron micrograph of Nafion stained with silver ions. The clusters appear as dark dots.


Hydration Shell Decrease Water Content Polar Cluster Perfluorosulfonic Acid Elastic Deformation Energy 
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  1. 1.
    S. C. Yeo and A. Eisenberg, J. Appl. Polym. Sci. 21, 875 (1977).CrossRefGoogle Scholar
  2. 2.
    A. Eisenberg and M. King, in Ion-Containing Polymers, Vol. 2. Physical Properties and Structure, R. S. Stein, ed., Academic, New York (1977).Google Scholar
  3. 3.
    L. Holliday, ed., Ionic Polymers, Applied Science Publishers Ltd., London (1975).Google Scholar
  4. 4.
    K. A. Mauritz and S. R. Lowry, Polym. Prep. Am. Chem. Soc. Div. Polym. Chem. 19 (2), 336 (1978).Google Scholar
  5. 5.
    R. A. Komoroski and K. A. Mauritz, J. Am. Chem. Soc. 100, 7487 (1978).CrossRefGoogle Scholar
  6. 6.
    A. Eisenberg, Macromolecules 3, 147 (1970).CrossRefGoogle Scholar
  7. 7.
    O. A. Ponomarev and I. A. Ionova, Vysokomol. Soedin. Ser. A 16, 1023 (1974).Google Scholar
  8. 8.
    T. D. Gierke, Ionic clustering in Nafion perfluorosulfonic acid membranes and its relationship to hydroxyl rejection and chlor-alkali current efficiency, presented at 152nd National Meeting, The Electrochemical Society, Atlanta, Georgia, October 10–14, 1977.Google Scholar
  9. 9.
    S. G. Cutler, Polym. Prep. Am. Chem. Soc. Div. Polym. Chem. 19 (2), 330 (1978).Google Scholar
  10. 10.
    K. A. Mauritz, C. J. Hora, and A. J. Hopfinger, Polym. Prep. Am. Chem. Soc. Div. Polym. Chem. 19 (2), 324 (1978).Google Scholar
  11. 11.
    K. A. Mauritz, C. J. Hora, and A. J. Hopfinger, in Ions in Polymers, Advances in Chemistry Series, A. Eisenberg, ed., No. 187, American Chemical Society, Washington, D.C. (1980), p. 123.Google Scholar
  12. 12.
    W. G. F. Grot, G. E. Munn, and P. N. Walmsley, Perfluorinated ion exchange membranes, presented at the 141st National Meeting of the Electrochemical Society, Houston, Texas, May 7–11, 1972.Google Scholar
  13. 13.
    H. Diebler and M. Eigen, Z. Phys. Chem. (Frankfurt) 20, 299 (1959).CrossRefGoogle Scholar
  14. 14.
    M. Eigen and K. Tamm, Z. Elektrochem. 66 (93), 107 (1962).Google Scholar
  15. 15.
    N. Bjerrum, Kgl. Danske Videnskab. Mat-Fys. Medd. 7 (9) (1926).Google Scholar

Copyright information

© Plenum Press, New York 1981

Authors and Affiliations

  • Anton J. Hopfinger
    • 1
  • Kenneth A. Mauritz
    • 2
  1. 1.Department of Macromolecular ScienceCase Western Reserve UniversityClevelandUSA
  2. 2.T. R. Evans Research CenterDiamond Shamrock CorporationPainesvilleUSA

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