Alternating current conductivity and dielectric relaxation of PANI:PVDF composites

Photovoltaic Laboratory Research and Technology Centre of Energy, Borj-Cedria Science and Technology Park, BP 95, 2050 Hammam-Lif, Tunisia

^a e-mail: saidisami@ymail.com

Received: 17 May 2013
Revised: 18 December 2013
Accepted: 3 February 2014
Published online: 21 April 2014

Abstract

In this work, PANI:PVDF composites films were prepared with different PANI contents (p = 1, 2, 3, 4 and 5%). The resulting films were dried at various temperatures such as 30, 90 and 120 °C. The alternating current mechanisms and dielectric relaxation and of PANI:PVDF films were studied using complex impedance spectroscopy over a wide range of temperature (303–453 K) and a frequency range (1 kHz to 1 MHz). We found that the ac conductivity in PANI:PVDF composite is governed by correlated barrier hopping (CBH) model. In dielectric loss modulus study, two relaxation processes were identified. The first peak was associated to Maxwell Wagner-Sillas (MWS) relaxation whereas the second one which obtained at higher frequency was attributed to the α_c relaxation. For PANI:PVDF film which dried at 30 °C, the MWS relaxation appears only at higher temperature. The temperature dependence of α_c relaxation was suitably fitted according to Vogel Flucher Temman model whereas MWS relaxation follows Arrhenius type behavior. The effect of drying temperature on microstructure and phase crystallization of PVDF in the composites was carried out using atomic force microscopy (AFM) and Fourier transform infrared (FTIR) spectroscopy. These results were used to find a reasonable correlation between microstructure and electrical properties.