Ionic conductivity of PEO-NH4ClO4 films by admittance spectroscopy: Correlation with crystallinity and morphology

In this paper we present a study of ionic conductivity versus salt fraction for PEO-NH4ClO4 films. Films with salt concentration x in the range 0 - 0. 35 (x is the weight fraction of the salt) were prepared for the study. X-ra y diffraction and differential scanning calorimetry were done to detect the different species present and to estimate the crystallinity of the films. The films have a wide variety of structures and exhibit a transformation fr om fractal to nonfractal morphology as x is increased. We attempt a correla tion of ionic conductivity with crystallinity and morphology of films with varying x and find that the fractal to compact crossover region has the hig hest ionic conductivity. [S0163-1829(99)12825-X].