CONTACT ION-PAIR FORMATION AND ETHER OXYGEN COORDINATION IN THE POLYMER ELECTROLYTES M[N(CF3SO2)(2)](2)PEO(N) FOR M=MG, CA, SR AND BA

The polymer electrolytes M[N(CF3SO2)(2)](2)PEO(n) for M = Mg, Ca, Sr a nd Ba have been investigated using infra-red spectroscopy, differentia l scanning calorimetry and impedance spectroscopy. The effects of vary ing concentration (n = 6-40) and temperature (25-95 degrees C) on the contact ion pair formation and cation coordination have been studied. Contact ion pairs are only found for the most concentrated samples (n < 9). Ion pairs occur with two types of structures: one type is found far samples containing Mg2+ and the other for samples with Ca2+, Sr2and Ba2+. The conductivities of the samples are discussed in terms of radii and coordination numbers of the cations.