The waterborne polyurethane (WPU) dispersions from the reaction of cycloaliphatic diisocyanates [4,4’-methylenebis(
cyclohexyl isocyanate) (H12MDI) and isophorone diisocyanate (IPDI)] and polyethylene glycol (PEG) with various
molecular lengths were synthesized using our modified acetone process. Differetial scanning calorimeter (DSC) and
Fourier transform infrared spectroscopy (FTIR) were utilized to characterize WPU films for the behavior of their crystallinity
and H-bonding of WPU films. The Tg value of WPU increases with increasing the molecular length of PEG,
whereas the Tm of WPU decreases with increasing PEG length. Alternating current (AC) impedance experiments were performed
to determine the ionic conductivities of WPU films. The WPU gel electrolytes exhibits an ionic conductivity as high
as ~10–5 S/cm at room temperature.