| US 7,540,991 B2 | ||
| Ion conductive polymer electrolyte membrane and production method for the same | ||
| Naoyuki Shimoyama, Saitama (Japan); Fumio Saitoh, Tokyo (Japan); Toru Kimura, Funabashi (Japan); and Masayuki Tobita, Isesaki (Japan) | ||
| Assigned to Polymatech Co., Ltd., Tokyo (Japan) | ||
| Filed on Jul. 01, 2005, as Appl. No. 11/173,721. | ||
| Claims priority of application No. 2004-198608 (JP), filed on Jul. 05, 2004. | ||
| Prior Publication US 2006/0004112 A1, Jan. 05, 2006 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. H05B 6/00 (2006.01) | ||
| U.S. Cl. 264—436 [264/435; 521/27; 429/33] | 5 Claims |
| 1. A method for manufacturing an electrolyte membrane formed of an ion conductive composition containing a lyotropic liquid
crystalline polymer having an ionic dissociative group and molecular chains orientated in a specific direction in which a
degree of orientation α of the liquid crystalline polymer is in a range of 0.45 or more and less than 1, as defined by an
equation (1) as follows:
Degree of orientation α=(180−Δβ)/180 (1) wherein Δβ 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; and wherein an anisotropy ratio of ionic conductivity of the membrane determined
from equation (2) below falls within a range of more than 1 and less than 60,
anisotropy ratio of ionic conductivity γ=(ionic conductivity in thickness direction)/(ionic conductivity in direction parallel
to surface) (2), the method comprising:
preparing the ion conductive composition containing the lyotropic liquid crystalline polymer having an ionic dissociative
group and a solvent, each molecular chain including a main chain and the ionic dissociative group being bonded to the main
chain;
developing liquid crystallinity of the liquid crystalline polymer in the composition, wherein said developing includes heating
the composition once to a temperature range in which liquid crystallinity is not developed in order to transform the lyotropic
liquid crystalline polymer into a uniform isotropic phase and then cooling the composition to a temperature range in which
liquid crystallinity is developed;
orientating the molecular chains of the lyotropic liquid crystalline polymer having developed liquid crystallinity, in a thickness
direction of the membrane; and
solidifying the ion conductive composition while the orientation of the molecular chains of the liquid crystalline polymer
is maintained.
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