Ionic conduction in polyphosphazene solids and gels: 13C, 31P, and 15N NMR spectroscopy and molecular dynamics simulations

摘要

Polyphosphazene single-substituent polymers were synthesized with the general formula [NP(OCH2CH2OCH2CH2XC H3)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 (T1) for d7-DMF solutions. Molecular dynamics simulations were also carried out in order to investigate the interactions within the polymer-salt-DMF complexes.