The waterborne polyurethane (WPU) dispersions synthesized from poly(ethylene glycol) (PEC), dimethylol propionic acid (DMPA), and isophorone diisocyanate (IPDI) with various DMPA contents were prepared from our modified acetone process. Differential scanning calorimeter (DSC), Fourier transform infrared spectroscopy (FT-i.r.), and wide-angle X-ray diffraction spectroscopy (WAXD) were utilized to characterize WPU films for the behavior of their crystallinity and H-bonding. Alternating current (AC) impedance experiments were performed to determine the ionic conductivities of WPU films and their corresponding gel electrolytes. One of the investigated WPU gel electrolytes exhibits an ionic conductivity as high as similar to 10(-5) S/cm at room temperature.