The dynamic ionic conductivity and polarizing morphology of poly(ethylene oxide)10:LiClO4 (PEO10:LiClO4) electrolyte membranes under different direct current electric fields (EFs) were simultaneously investigated. PEO molecular chains were found to rearrange during the migration of charge carriers, and the rearrangement of PEO molecular chains dramatically affected the conductivity of the electrolyte membrane. No noticeable differences of conductivity and polarizing morphology between the heating and cooling process were observed when the EF was absent. However, the conductivity of the membrane was remarkably enhanced after applying an EF and after carrying out a heatingcooling loop. Differential scanning calorimetry and wide-angle X-ray diffraction of the sample with different treatments of both EFs and heatingcooling loops showed that the conductivity enhancement or reduction after loading special EFs and heatingcooling loops were attributed to the change of both the crystallite size of certain diffraction planes and the thickness of PEO lamellae. (C) 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012