Polyethylene oxide with lithium trifluoromethane sulphonate; an NMR study

A study of the NMR parameters of a range of high-molecular-weight poly(ethylene oxide) samples doped with substantial concentrations of lithium trifluoromethane sulphonate is reported. The measurements, taken over a range of temperatures from 100 to 370 K, include (i) the T 1 values of fluorine, protons, and lithium, (ii) the ratios of the amplitudes of the different types of signals from one nuclear species, measured for each of the nuclear species present, and (iii) the ratios of the amplitudes of the signals from the fluorine and lithium nuclei. The main impact of the study is to present evidence against the simple partition of the NMR signals into crystalline and elastomeric portions and to document the observation that significant numbers of lithium nuclei are not observed by the NMR technique, strongly suggesting that there are inequivalent lithium sites.