Nonlinear enhancement of the dielectric properties of PVA-Al2O3 nanocomposites
Ram J. Sengwa, Shobhna Choudhary
Volume 2, Issue 4, Page 280-287, Year 2017 | DOI: 10.5185/amp.2017/415
Keywords: Polymer nanocomposites, dielectric properties, electrical conductivity, polymer dynamics, X-ray diffraction.
Abstract: Dielectric dispersion and relaxation behaviour of aqueous solution grown polymeric nanocomposite films consisting of poly(vinyl alcohol) (PVA) and alumina (Al2O3) (PVA–x wt% Al2O3 (x = 0, 1, 3 and 5)) have been studied in the frequency range from 20 Hz to 1 MHz by employing dielectric relaxation spectroscopy (DRS). It is found that at constant frequency, the real part of complex permittivity increases nonlinearly with the increase of Al2O3 nanoparticles concentrations in the PVA matrix, whereas it decreases with increase of frequency at constant concentration of Al2O3. The temperature dependent investigation on PVA–3 wt% Al2O3 film reveals that the dielectric properties increase with the increase of temperature confirming its thermally activated dielectric behaviour. The ac electrical conductivity of the nanocomposites increases and the impedance values decreases with the increase of frequency which are moderately affected by Al2O3 concentrations (x = 0 to 5 wt%) and temperatures (30 to 60 °C). The dc conductivity and relaxation time of PVA chain segmental motion of the nanocomposites obey the Arrhenius behaviour. The X-ray diffraction (XRD) study reveals that the crystallite size and amorphous phase of PVA increase with the increase of Al2O3 concentration in the PVA–Al2O3 nanocomposites. Results of this study confirm the suitability of PVA–Al2O3 nanocomposite materials as tunable nanodielectric for their use as insulator and substrate in the fabrication of microelectronic devices operated at audio and radio frequencies. Copyright © 2017 VBRI Press.