Mechanism of ion transport in YSZ-dispersed polymer nanocomposite films: an analysis by vibrational spectroscopy approach

We report a novel and interesting finding on nanoceramic filler-induced symmetry lowering of ClO ₄ ^? anion from ( {T_d} leftrightarrow {C_{2nu }} ) in polymer nanocomposite films, based on poly(ethylene oxide)₈–LiClO₄?+?x wt.% nano-Yttria-stabilized zirconia (YSZ) in sharp contrast to the lowering pattern from ( {T_{text{d}}} leftrightarrow {C_{{3}nu }} ) in the polymer–salt complex (undispersed) film. This is evidenced by a systematic absence of E ₁ mode in YSZ-dispersed nanocomposite films. Based on the experimental evidences from Fourier transform infrared, conductivity, and transmission electron microscopy analysis, an ion conduction mechanism has been proposed to probe the interaction prevailing among various components of the nanocomposite film. An explanation for the concentration dependence of ion transport phenomena has been proposed in terms of filler–ion–polymer interaction. The central idea of the proposed ion transport mechanism lies in a practically feasible Lewis acid–base type interaction between dipolar nanofiller having Lewis acid characteristics with the anions (ClO ₄ ^? ) and ether oxygen sites of the host polymer acting as the Lewis base.