Positron annihilation and ion-conductivity studies of PEO–NH4ClO4 complexes

We present positron annihilation lifetime spectroscopy (PALS) results on the polymer electrolyte [PEO](1−x)–[NH4ClO4](x), for different x, denoting weight fraction and their correlation to other properties. Variation of composition through change in x causes the ion conductivity and crystallinity to vary. We find that the changes are well reflected in variation of the positron annihilation lifetime components and their intensities. Although three distinct positron lifetime components have been identified, most of the earlier work considered only the longest component arising out of the noncrystalline regions in their explanation of ion-conductivity variation with temperature. Our room temperature study shows a new correlation. The average and bulk lifetimes, calculated from the two shorter lifetime components, is less at compositions with higher ion conductivity, suggesting some contribution of the crystalline regions to conductivity.