(JP11250922-A)   NOVELTY - A proton exchange membrane comprising a perfluorosulfonic acid having silica particles embedded in it in a concentration comprised 0.01-50 wt% and dimensions comprised 0.001-10 microns is characterized in that the membrane comprises both an amorphous and a crystalline phase and the ratio is adjusted by means of a controlled thermal treatment at a temp higher than Tg.    USE - It is claimed that the cell is a fuel cell.    ADVANTAGE - The membrane contains both an amorphous and a crystalline phase where the ratio can be adjusted by means of a controlled thermal treatment at a temperature higher than the glass transition temperature, controlled by an X-ray spectrometer. The fuel cells can be operated at temperatures of 100-160degreesC. There is a large flexibility of choice of fuel to be fed to the anode (light alcohols, hydrogen from steam reforming or partial oxidation of alcohols or fossil hydrocarbon fuels, or natural gas). The thermal treatment produces a controlled transition phase of part of the polymer with the degree of conversion from the amorphous phase to the crystalline phase controlled by X-ray diffraction during the thermal treatment. The mechanical properties of the film are markedly improved. Operation of the fuel cell at 100-160 degreesC is possible for prolonged periods without any risk of dehydration or non-controlled transition phases. Poisoning of noble metal based catalysts by carbon monoxide and other organic compounds is eliminated and the oxidation kinetics of fuels such as methanol and ethanol is increased. In the case of cells fed with light alcohols, migration of these fuels through the membrane is reduced as indirectly demonstrated by the open circuit voltage which reaches high values. The diffusion coefficient of the methanol species is about one thousand times lower than the conventional value.    (US6156184-A)   NOVELTY - A proton exchange membrane comprising a perfluorosulfonic acid having silica particles embedded in it in a concentration comprised 0.01-50 wt% and dimensions comprised 0.001-10 microns is characterized in that the membrane comprises both an amorphous and a crystalline phase and the ratio is adjusted by means of a controlled thermal treatment at a temp higher than Tg.    USE - It is claimed that the cell is a fuel cell.    ADVANTAGE - The membrane contains both an amorphous and a crystalline phase where the ratio can be adjusted by means of a controlled thermal treatment at a temperature higher than the glass transition temperature, controlled by an X-ray spectrometer. The fuel cells can be operated at temperatures of 100-160degreesC. There is a large flexibility of choice of fuel to be fed to the anode (light alcohols, hydrogen from steam reforming or partial oxidation of alcohols or fossil hydrocarbon fuels, or natural gas). The thermal treatment produces a controlled transition phase of part of the polymer with the degree of conversion from the amorphous phase to the crystalline phase controlled by X-ray diffraction during the thermal treatment. The mechanical properties of the film are markedly improved. Operation of the fuel cell at 100-160 degreesC is possible for prolonged periods without any risk of dehydration or non-controlled transition phases. Poisoning of noble metal based catalysts by carbon monoxide and other organic compounds is eliminated and the oxidation kinetics of fuels such as methanol and ethanol is increased. In the case of cells fed with light alcohols, migration of these fuels through the membrane is reduced as indirectly demonstrated by the open circuit voltage which reaches high values. The diffusion coefficient of the methanol species is about one thousand times lower than the conventional value.