Ion conductive polymer electrolyte membrane and production method for the same

The present invention provides an electrolyte membrane (11) formed of an ion conductive composition. Said composition contains a liquid crystalline polymer having an ionic dissociativegroup. Molecular chains of the liquid crystalline polymer are orientated in a specific direction. The degree of orientation ± of the liquid crystalline polymer is in a range of 0.45 or more and less than 1, as defined by equation (1) as follows; Degree of orientation ± = (180-B/180) (1), wherein B is a full width at half maximum of a peak in an X-ray diffraction intensity distribution pattern obtained by measuring an intensity distribution from 0 to 360 degrees in the azimuthal angle direction, at a peak scattering angle, in an X-ray diffraction image of the electrolyte membrane (11). Ionic conductivity in a thickness direction of the membrane (11) is higher than the ionic conductivity in a direction parallel to a surface of the membrane (11). The present invention also provides a method for manufacturing an electrolyte membrane (11) formed of an ion conductive composition.