EFFECT OF OLIGO(ETHYLENEOXY)CYCLOTRIPHOSPHAZENES, TETRAGLYME, AND OTHER SMALL MOLECULES ON THE IONIC-CONDUCTIVITY OF THE POLY[BIS(METHOXYETHOXYETHOXY)PHOSPHAZENE] (MEEP) LITHIUM TRIFLATE SYSTEM/
Hr. Allcock et al., EFFECT OF OLIGO(ETHYLENEOXY)CYCLOTRIPHOSPHAZENES, TETRAGLYME, AND OTHER SMALL MOLECULES ON THE IONIC-CONDUCTIVITY OF THE POLY[BIS(METHOXYETHOXYETHOXY)PHOSPHAZENE] (MEEP) LITHIUM TRIFLATE SYSTEM/, Macromolecules, 30(11), 1997, pp. 3184-3190
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.