A new series of solid polymer electrolyte materials based on the poly(organophosphazene) system has been designed and synthesized. The new polymers contain linear or branched oligoethyleneoxy side chains. The polymers were characterized by 31 P, 13 C, and 1 H-NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry, and elemental analysis. The ambient temperature (25°C) ionic conductivities of the polymers complexed with lithium triflate were measured by complex impedance analysis. The polymers that bear linear oligoethyleneoxy side chains [NP{O(CH2CH2O)n-CH3}2], have low glass transition temperatures that range from -84 to -75°C. These polymers have properties that are similar to those of the classical counterpart poly[bis(2-(2-methoxyethoxy)ethoxy)-phosphazene. They have low dimensional stabilities and undergo viscous flow even at room temperature. The polymers with branched oligoethyleneoxy side chains (podands) have similar glass transition temperatures, in the range of -82 to -79°C. However, the bulk dimensional stabilities of the branched polymers are significantly higher than those of the corresponding linear side chain series. The branched side chain polymers resist viscous flow and readily form thin, free-standing films. The podand polymers also dissolve lithium triflate to form ionically conducting materials with conductivity levels similar to those of the polymers bearing linear side chains.

A series of mixed-substituent poly(organophosphazenes) with the general structure {NP[OCH2CH2OCH2CH2OCH3] x [O(CH2) y CH3]2-x } n , where x = 1 and y = 2−9 was synthesized. These polymers are candidates for use as solid polymeric, ionic conduction media. The polymers were characterized by 1H, 13C, and 31P nuclear magnetic resonance spectroscopy, gel permeation chromatography, elemental microanalysis, infrared spectroscopy, and differential scanning calorimetry. The polymers were complexed with LiSO3CF3 and ambient temperature (25 °C) ionic conductivity studies were performed with the use of complex impedance analysis. The effect of changes in the length of the alkyl component of the alkoxy groups on conductivity was examined. A maximum conductivity as a function of the concentration of lithium triflate was found for each system. The conductivity decreased with an increase in the alkyl group side-chain length. These polymers were compared to the polyphosphazene single-substituent polymer [NP(OCH2CH2OCH2CH2OCH3)2] n , as well as to the n-alkyloxy single-substituent polymers {NP[O(CH2) x CH3]2} n , where x = 2−9.

A series of mixed-substituent poly(organophosphazenes) with ethyleneoxy side groups has been synthesized. These polymers possess multiple electron-donor coordination sites that can form complexes with metal salts and generate "solid electrolyte" behavior. The polymers were characterized by 31 P, 1 H, and 13 C NMR spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and elemental analysis. All the mixed-substituent polymers have low glass transition temperatures, from -70 to -56 °C, as well as at least one melting transition. Several polymer-lithium triflate complexes were examined by impedance analysis. The maximum conductivities for these polymers ranged from 1.6 × 10 -6 to 3.9 × 10 -5 S cm -1 .

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Polyphosphazene single-substituent polymers were synthesized with the general formula [NP(OCH2CH2OCH2CH2XCH3)2] where X = oxygen for polymer 5 or X = sulfur for polymer 6. Characterization of these materials made use of 1H, 13C, 15N, and 31P nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry, gel permeation chromatography, and elemental microanalysis. The polymers were complexed with LiSO3CF3 and AgSO3CF3 and examined both as solid electrolyte media and in the presence of dimethylformamide solvent. The ionic conductivities of these materials were determined at 25 °C through the use of complex impedance analysis. The mechanism of ionic conduction in the polymer−salt complexes was probed through an examination of 13C, 31P, and 15N NMR shifts and 13C NMR spin−lattice relaxation times (T 1) for d 7-DMF solutions. Molecular dynamics simulations were also carried out in order to investigate the interactions within the polymer−salt−DMF complexes.