EP1112301-A1  See references of WO 0015691A1US6828353-B1  AB J 09245818.;  Bauer et al; "Electrochemical characterisation of sulfonated polyetherketone membranes"; Journal of New Materials for Electrochemical Systems, 3 pp. 93-98 (2000).;  Chunxiao et al; "The Microstructure of Polyetheretherketone Containing Biphenyl Linkages and the Properties of the Sulphonated Polymer"; Chemical Journal of Chinese Universities, vol. 15, No. 2, pp. 240-243 (1994) including English translation.;  Clark et al; "Trifluoromethylated poly(ether sulfone)s"; Polymer vol. 35 No. 11; pp. 2432-2437 (1994).;  Lloyd et al and Wightman et al; "Poly(aryl ether) Membranes for Reverse Osmosis"; ACS Symposium Series 153, Synthetic Membranes: vol. 1, Desalination, pp. 326-349. (1981).;  Shobha, et al; "Synthesis and Characterization of Sulfonated Poly(Arylene Ether)s Based on Functionalized Triphenyl Phosphine Oxide for Proton Exchange Membranes"; Polymer Preprints 2000, 41(1), pp. 180-181; and pp. 236-239.;  Ueda et al; "Synthesis and Characterization of Aromatic Poly (ether Sulfone)s Containing Pendant Sodium Sulfonate Groups"; Journal of Polymer Science, Part A: Polymer Chemistry, vol. 31, pp. 853-859 (1993).;  Wang et al; "Sodium sulfonate-functionalized poly(ether ether ketone)s"; Macromol. Chem. Phys. 199, pp. 1421-1426 (1998).;  Wang et al; "Synthesis of poly(ether ether ketone) containing sodium sulfonate groups as gas dehumidification membrane material"; Macromol. Rapid Commun. 19; pp 135-137 (1998).;  Wang et al; "Synthesis of poly(ether ether ketone) with high content of sodium sulfonate groups and its membrane characteristics"; Polymer 40 (1999); pp. 795-799.US6969755-B2  Bauer et al; "Electrochemical characterisation of sulfonated polyetherketone membranes"; Journal of New Materials for Electrochemical Systems, 3 pp. 93-98 (2000).;  Chunxiao et al; "The Microstructure of Polyetheretherketone Containing Biphenyl Linkages and the Properties of the Sulphonated Polymer"; Chemical Journal of Chinese Universities, vol. 15, No. 2, pp. 240-243 (1994) including English translation.;  Clark et al; "Trifluoromethylated poly(ether sulfone)s"; Polymer vol. 35 No. 11; pp. 2432-2437 (1994).;  Lloyd et al and Wightman et al; "Poly(aryl ether) Membranes for Reverse Osmosis"; ACS Symposium Series 153, Synthetic Membranes: vol. 1, Desalination, pp. 326-349. (1981).;  Shobha, et al; "Synthesis and Characterization of Sulfonated Poly(Arylene Ether)s Based on Functionalized Triphenyl Phosphine Oxide for Proton Exchange Membranes"; Polymer Preprints 2000, 41(1), pp. 180-181; and pp. 236-239.;  Ueda et al; "Synthesis and Characterization of Aromatic Poly (ether Sulfone)s Containing Pendant Sodium Sulfonate Groups"; Journal of Polymer Science, Part A: Polymer Chemistry, vol. 31, pp. 853-859 (1993).;  Wang et al; "Sodium sulfonate-functionalized poly(ether ether ketone)s"; Macromol. Chem. Phys. 199, pp. 1421-1426 (1998).;  Wang et al; "Synthesis of poly(ether ether ketone) containing sodium sulfonate groups as gas dehumidification membrane material"; Macromol. Rapid Commun. 19; pp135-137 (1998).;  Wang et al; "Synthesis of poly(ether ether ketone) with high content of sodium sulfonate groups and its membrane characteristics"; Polymer 40 (1999); pp. 795-799.