Ionic Conduction in Polyphosphazene Solids and Gels:  <SUP>13</SUP>C, <SUP>31</SUP>P, and <SUP>15</SUP>N NMR Spectroscopy and Molecular Dynamics Simulations

Polyphosphazene single-substituent polymers were synthesized with the general formula [NP(OCH<INF>2</INF>CH<INF>2</INF>OCH<INF>2</INF>CH<INF>2</INF>XCH<INF>3</INF>)<INF>2</INF>] where X = oxygen for polymer <BO>5</BO> or X = sulfur for polymer <BO>6</BO>. 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 LiSO<INF>3</INF>CF<INF>3</INF> and AgSO<INF>3</INF>CF<INF>3</INF> 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<INF>1</INF>) for d<INF>7</INF>-DMF solutions. Molecular dynamics simulations were also carried out in order to investigate the interactions within the polymer−salt−DMF complexes.