Dielectric and conductivity studies of 90 MeV O7+ ion irradiated poly(ethylene oxide)/montmorillonite based ion conductor

In the present work effect of 90 MeV O7+ ions with five different fluences on poly(ethylene oxide) (PEO)/Na+-montmorillonite (MMT) nanocomposites has been investigated. PEO/MMT nanocomposites were synthesized by solution intercalation technique. With the increase in irradiation fluence, gallery spacing of MMT increases in the composite and an exfoliated nanostructure is obtained at the fluence of 5 x 10(12) ions/cm(2) as revealed by X-ray diffraction results. Highest room temperature ionic conductivity of 4.2 x 10(-6) S cm(-1) was found for the fluence 5 x 10(12) ions/cm(2), while the conductivity for unirradiated polymer electrolyte was found to be 7.5 x 10(-8) S cm(-1). The increase in intercalation of PEO chains inside the galleries of MMT results in the increase in interaction between Na+ cation and oxygen heteroatom leading to the increase in ionic conductivity of the composites. Surface morphology and interactions among the various constituents in the nanocomposites at different fluence have been examined by scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The appearance of peak for each fluence in the loss tangent suggests the presence of relaxing dipoles in the polymer nanocomposite electrolyte films. With the increase in ion fluence the peak shifts towards higher frequency side, suggesting decrease in the relaxation time.