Ionic conductivity and plasticizing effect in the system poly(ethyleneoxide)9/Li(CF3SO3)-poly(perfluoroethylmethyloxide)

The ionic conductivity of the system P(EO)(9)/LiCF3SO3 may be increased by two orders of magnitude at room temperature by adding poly(perfluorinated ethylenmethylenoxide) (PPFEMO). The highest conductivity at 20 degrees C, 4.0 x 10(-5) Omega(-1) cm(-1), was obtained for a ratio PPFEMO/PEO = 1.00. The conductivity is enhanced when the amount of plasticizer is increased, however the effect is more pronounced at the lower concentration of PPFEMO. The Tg of the system decreases from -21.5 degrees C to -45 degrees C by the addition of the PPFEMO and the transition is more clearly observable at higher concentration of plasticizer. The dielectric measurements indicate that phase Separation takes place in these materials and, in contrast to more "conventional" plasticizers, the salt is completely insoluble in the perfluorinated polymer. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.