Dielectric relaxation behavior of three-phase MWCNTs-PANI polystyrene nanocomposites

Abstract

Polymer nanocomposites consisting of multiwalled carbon nanotubes (MWCNTs), polyaniline (PANI), and polystyrene (PS) were prepared at different MWCNT weight ratios and fixed amount of PANI (0.2 wt%). Impedance, dielectric constant, dielectric loss, and electrical conductivity for these composites were investigated as a function of applied field and MWCNTs content at room temperature. Obtained results indicated that adding 0.2 wt% PANI polymer to MWCNTs-PS system will enhance electrical conductivity and polar character while reduce the percolation threshold from 0.8% to 0.2% MWCNTs of nanocomposites. Relaxation behavior of prepared nanocomposites showed interesting results. In general, impedance results showed that all samples contain capacitor and resistor elements. Increasing of MWCNTs amount will reduce the distance between CNTs–CNTs in the CNTs–polymer network, and the resistor element become more pronounced. Moreover, at high level of MWCNTs content the relaxation behavior is mostly due to conductivity relaxation with single value of relaxation time. The addition of PANI (0.2% PANI) to CNT–polymer or CNT–CNT networks will introduce easy pathway for carriers to transfer through network leading to increase the electrical conduction for composites. Relaxation results indicated that the relaxation behavior of prepared nanocomposite is mostly due to conductivity relaxation above 0.2 wt% nanocomposite.