TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The blend membrane is additionally doped with a specific quantity of phosphoric acid. The phosphoric acid exhibits a degree of doping of 40-300%.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Claimed): The preparation of phosphonated monomers and polymers, comprises carrying out aromatic nucleophilic substitution reaction of Arbuzov type by replacing fluorine atoms with phosphonic acid groups, comprising dissolving or suspending partial or perfluorinated low or high molecular weight aromatic compounds in phosphonating agent, heating the mixture to a temperature of 60-200 degrees C for 30 minutes to 12 hours optionally under the addition of a further solvent or a combination of different solvents, distilling or removing the excess of phosphonating agent, cooling the reaction mixture, mixing the phosphonated monomer or polymer with water and/or an alcohol, and isolating the phosphonated monomer or polymer by recrystallization and/or dialysis or precipitation. Preferred Components: The phosphonating agent is tris(trialkylsilyl)phosphite, preferably tris(trimethylsilyl)phosphite.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The phosphonated polymer comprises perfluorinated and phosphonated aromatic groups in its main and/or side chain. The degree of phosphonation of the polymer is upto 1 phosphonic acid per fluorinated phenyl group. The polymer to be phosphonated is poly(2,3,4,5,6-pentafluorostyrene) or poly( alpha -methyl-2,3,4,5,6-pentafluorostyrene), which is present in pure form or as a random copolymer or a block copolymer (linear (multi)block copolymer or graft copolymer), where 2,3,4,5,6-pentafluorophenyl group of the polymer is phosphonated in 4th position. The proton conductivity of the obtained polymeric phosphonic acid is several times higher than the proton conductivity of a non-fluorinated aromatic high molecular weight phosphonic acid. The basic polymer comprises polybenzimidazole. The mixing ratio of phosphonated polymer and basic polymer is 99 mole% of phosphonated polymer and 1 mole% of basic polymer or 1 mole% of phosphonated polymer and 99 mole% of basic polymer. The blend is additionally added with a specific quantity of sulfonated polymer. EXAMPLE - Poly(pentafluorostyrene) (6.817 g) and tris(trimethylsilyl)phosphite (20.96 g) were heated to 170 degrees C in an oil bath for 8 hours under stirring to obtain a clear solution. Then the reaction mixture was worked up to obtain phosphonated poly(pentafluorostyrene).