Samantaray B. K.: Studies of dielectric relaxation and ac conductivity behaviour of plasticized polymer nanocomposite electrolytes

The frequency dependent dielectric and conductivity behavior of a plasticized polymer nanocomposite electrolytes (PPNCEs) based on poly(ethylene oxide) + NaClO4 with dodecyl amine modified montmorillonite (DMMT) as the filler and poly(ethylene glycol) as the plasticizer have been studied. The formation of nanocomposites and changes in the structural and microstructural properties of the materials were investigated by x-ray diffraction (XRD) and optical microscopy techniques. Studies of dielectric properties at lower frequencies show that the relaxation contribution is superimposed by electrode polarization effect. The appearance of peak for each concentration in the loss tangent suggests the presence of relaxing dipoles in the polymer nanocomposite electrolyte (PNCE) films. On addition of plasticizer, the peak shifts towards higher frequency side suggesting the speed up the relaxation time. The variation of ac conductivity with frequency obeys Jonscher power law except a small deviation in the low frequency region due to electrode polarization effect. The dc conductivity increases with increase in plasticizer concentration. Analysis of frequency dependence of dielectric and modulus formalism suggests that the ionic and polymer segmental motions are strongly coupled