Significantly enhanced dielectric properties and chain segmental dynamics of PEO/SnO2 nanocomposites

Abstract

Poly(ethylene oxide) (PEO) matrix- and tin oxide (SnO2) nanofiller-based polymer nanocomposite films were prepared by solution cast followed by melt press. The effect of SnO2 concentration (i.e. 1, 3, and 5 wt%) on the structure, dielectric permittivity, and chain segmental motion of PEO was investigated with X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and dielectric relaxation spectroscopy (DRS) techniques. Results reveal that the dispersion of SnO2 nanoparticles has enormously altered the contents of different crystallite phases of the PEO and some amount of the degree of crystallinity. The DRS study in the range of 20 Hz–1 MHz at 30 °C confirmed that the complex dielectric permittivity and electrical conductivity at lower frequencies increased largely on the dispersion of SnO2 nanoparticles in the PEO matrix which was attributed to the contribution of interfacial polarization effect, moreover, a significant increase was also noted in the molecular polarization at higher frequencies. The relaxation processes corresponding to Maxwell–Wagner–Sillars mechanism and PEO chain segmental motion were analysed from the electric modulus spectra. The chain segmental dynamics and dc electrical conductivity have nonlinearly enhanced with the increase in SnO2 content in the polymer structure. The temperature-dependent dielectric and relaxation behaviour of PEO-3 wt% SnO2 film was also reported. It was observed that the relaxation time and electrical conductivity of the film exhibited Arrhenius behaviour of low activation energies.