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

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