The pulsed field gradient spin echo technique has been used to measure
the self-diffusion coefficients of both the cation and anion in LiCF3
SO3 PEO(n) systems as a function of concentration and temperature. In
addition, the ionic conductivities were determined by ac conductivity
measurements. The temperature dependence of both conductivity and ion
diffusivities could be very well described by the Vogel-Tamman-Fulcher
equation. Predicted values for ionic conductivity were obtained from
the NMR diffusivities using the Nernst-Einstein equation and compared
with those from direct measurement. It is clear that at higher reduced
temperatures and/or lower salt concentrations, there is an increasing
degree of ionic association or correlated motions of neighbouring cat
ions and anions which give rise to deviations from the Nernst-Einstein
equation. The molecular mobility of the polymer chains in these syste
ms has also been studied by NMR measurements of the proton transverse
relaxation behaviour. It has been found that the addition of salt does
not affect the critical entanglement molecular weight of the polymer
but it does increase the segmental relaxation time. Below the entangle
ment molecular weight the polymer chain dynamics can be described by t
he Rouse model. Above the critical entanglement molecular weight, a mo
del due to Brereton can be used, and the NMR data have been shown to b
e consistent with a constant chain length between entanglements, the r
elaxation times varying with salt concentration in a manner predicted
from the conductance measurements. It is concluded that the dissolved
salt increases the energy barriers to polymer segmental motion, but no
t the entangled structure of the polymer.