Influence of ionic liquid on the dielectric relaxation behavior of SWCNT reinforced poly(vinyl alcohol) based nanocomposites

Abstract

Polymer nanocomposites based on single-walled carbon nanotubes (SWCNT) and poly(vinyl alcohol) have been successfully prepared using a solvent casting approach. The dispersion pattern of SWCNT in the PVA matrix has been analyzed by a high-resolution transmission electron microscope (HRTEM). The mechanical and thermal stability of the films were assessed. The effect of SWCNT loading and imidazolium-based ionic liquid on the dielectric relaxation behavior of the PVA-based nanocomposites has been explored in the frequency range of 1 to 106 Hz at room temperature. The dielectric properties such as dielectric permittivity (εʹ), real and imaginary impedance (Zʹ and Zʹʹ), AC conductivity (σac) as well as Nyquist plot of the fabricated nanocomposites were explored in the presence and absence of ionic liquid (IL). The dielectric permittivity and AC conductivity increased with an increase in SWCNT loading and presence of IL due to the enhanced interfacial polarization of the SWCNT at the interface and proper dispersion of SWCNT throughout the polymer matrix. The decrease in impedance (Zʹ and Zʹʹ) with the increase in SWCNT loading is due to the enhanced proximity between the conductive channels. The reduction in semicircular area under the Nyquist plot in presence of IL and increasing SWCNT loading indicated the capacitive nature of fabricated nanocomposites and a decrease in bulk resistivity.