Influence of SnO2 nanoinclusions on the structural and dielectric properties of (PVA–PEO)/SnO2 nanocomposites

Abstract

Nanofiller concentration dependent, tunable-type structural, dielectric, thermo-mechanical, and optical properties of the polymer nanocomposites (PNCs) have established them as technologically smart multifunctional materials for advances in stretchable and flexible-type organoelectronic, optoelectronic, and energy harvesting/storage devices. In this work, organic-inorganic hybrid PNC films comprising poly(vinyl alcohol) (PVA) and poly(ethylene oxide) (PEO) blend as host matrix (PVA–PEO; 50–50 wt%) dispersed with varying concentration of tin oxide (SnO2) nanoparticles up to 5 wt% have been prepared by the solution-cast method. The influence of SnO2 loading on the percent crystallinity of the host matrix and the structural parameters of the PEO crystallites has been examined by the X-ray diffraction (XRD) measurements of the PNC films. The results reveal that the percent crystallinity of the semicrystalline (PVA–PEO) matrix gradually enhanced, whereas the interlayer spacing, crystallite size, and interchain separation of the PEO crystallites varied anomalously with the increase of SnO2 concentration in the PNC films. The complex dielectric permittivity, alternating current (ac) electrical conductivity, and electric modulus dispersion over the broad frequency range (20 Hz–1 MHz) of these (PVA–PEO)/SnO2 films has been characterized by employing the dielectric relaxation spectroscopy (DRS). It has been observed that 1 wt% SnO2 nanoinclusion abruptly reduced the interfacial, dipole polarizations, and also electrical conduction of the host matrix, whereas considerably enhanced hindrance to the PEO chain segmental motion studied at 30 °C. The temperature dependent study (30–60 °C) of the representative PNC film of 3 wt% nanofiller reveals its thermally activated non-linear dielectric polarization at fixed frequency and also Arrhenius behaviour of the dielectric relaxation processes of significantly low activation energy (≃ 0.14 eV). The structural, dielectric, and electrical properties of the (PVA–PEO)/SnO2 films have been critically analyzed for their suitability as controllable low dielectric permittivity polymer nanodielectric (PNDs) materials for biodegradable electronic devices.