Dynamics of Poly(ethylene oxide) around Its Melting Temperature

This study has focused on the ionic conductivity (of impurities) and the changes in relaxation behavior of semicrystalline poly(ethylene oxide) (PEO) around its melting temperature of the crystalline regions. Our main aim was to understand the implications of nucleation and growth of spherulitic structures on the general dynamical properties of the polymer chains and how these dynamical alterations affect the ionic conductivity. Impedance data have been scaled and analyzed under conductivity and modulus formalisms over wide ranges of frequency and temperature. The analysis of the scaled formalisms indicates that both the conductivity and the structural relaxation mechanisms are temperature independent above the melting point of PEO. However, below the melting, point, the slow crystallization of PEO leads to growth of spherulites and also to the formation of interphase regions. These morphological changes result in a hindered long-range dc conductivity, which, in turn, leads to a decoupling of the dc conductivity and the structural relaxation below the melting point of PEO.