US Patent 7307138 Polymer electrolytes and process for their preparation

A sulfonated aromatic polyether ketone of the formula (II)[Ar—O—Ar′—CO—Ar′—O—Ar—CO—Ar″—CO—]   (II)in which from 1% to 100% of the O-phenylene-CO units are substituted with an SO3M group and sulfonated and unsulfonated O-phenylene-CO units can be in any desired sequence with respect to one another, the radicals Ar, Ar′ and Ar″ independently of one another are substituted or unsubstituted 1,2-, 1,3- or 1,4-phenylene rings, andM, taking into account the ionic valencies, comprises one or more elements selected from the following group: H, NR4+, where R is H or C1-C4-alkyl, or an alkali metal or alkaline earth metal or a metal from subgroup 8, and is preferably H, NR4+, Li, Na, K, Ca, Mg, Fe or Pt.