EFFECT OF OLIGO(ETHYLENEOXY)CYCLOTRIPHOSPHAZENES, TETRAGLYME, AND OTHER SMALL MOLECULES ON THE IONIC-CONDUCTIVITY OF THE POLY[BIS(METHOXYETHOXYETHOXY)PHOSPHAZENE] (MEEP) LITHIUM TRIFLATE SYSTEM/

Four small molecule cyclotriphosphazenes bearing linear and branched e thyleneoxy units have been synthesized as ion transport assistance (IT A) species to improve the ionic conductivity of poly[bis(methoxyethoxy ethoxy)phosphazene] (MEEP)-lithium triflate systems. The cyclotriphosp hazenes were characterized by (31)p, H-1, and C-13 nuclear magnetic re sonance spectroscopy and infrared spectroscopy. MEEP was complexed wit h lithium triflate and combined with different amounts of each of the ITA molecules. Room temperature conductivity measurements and differen tial scanning calorimetry experiments were carried out on each of thes e mixtures. The effect of concentration of the ITA molecules and salt on the ionic conductivity of MEEP is reported. The general trend obser ved is an increased conductivity with increasing ITA molecule concentr ation. The effect of branching in the ITA molecule on the ionic conduc tivity was studied by comparing influence of branched versus linear si de groups; Differential scanning calorimetry indicate that these small molecules play a role in ionic cross-linking. The influence of high d ielectric solvents on the ionic conductivity of MEEP/LiSO3CF3 systems was also studied. These solvents generated higher conductivities at th e same concentration than did the cyclotriphosphazene ITA species.