Investigation of the lamellar grains of graft-type polymer electrolyte membranes for hydrogen fuel cell application using ultrasmall-angle x-ray scattering

This observation indicates: i) The formation of the lamellar grains; ii) The rapid changes in characteristic sizes of the lamellar grains compared with the lamellar stacks; and iii) The newly generated phases consisting of only the graft materials. These findings explain why the lamellar grains and the graft chains play an important role in the higher proton conductivity and compatible tensile strengths of the membranes, compared with Nafion, at the immersed and severe operating conditions.