PHASE-DIAGRAM OF THE POLY(ETHYLENE OXIDE)CA(CF3SO3)2 SYSTEM

Variable-temperature powder X-ray diffraction (VTXRD) and differential scanning calorimetry (DSC) have been used to determine the poly(ethyl ene oxide):Ca(CF3SO3)2 phase diagram. A new crystalline complex with a stoichiometry corresponding to 6 ether oxygens/Ca2+ ion has been iden tified. The data show that this complex exhibits a phase transition at approximately 200-degrees-C between a low temperature, alpha and high temperature, beta, polymorph; at higher temperature the beta polymorp h melts incongruently. At lower salt contents, precipitation of Ca(CF3 SO3)2 from the amorphous phase upon increasing the temperature is obse rved, indicating a negative entropy for the dissolution of the salt in the polymer. Finally, temperature dependent conductivities are presen ted for a range of compositions.