Effect of PANI rate percentage on morphology, structure and charge transport mechanism in PANI-PVDF composites above percolation threshold

Polyaniline-Poly(vinylidene) fluoride (PANI-PVDF) composites were prepared by adding PANI to the PVDF by different weight percentages p % (p = 0, 5, 10, 20, ... until 100%). The dc and ac electrical conductivity were studied as a function of PANI percentage in the temperature range 303-453 K. The percolation threshold was found to be equal to 2.95%. When the amount of PANI varies from 5 to 30%, the charge transport mechanism was found to be governed by Mott's three-dimensional variable range hopping model and the dc conductivity decreases within this range. For p > 30%, the conductivity increases and the charge transport mechanism are better fitted by a fluctuation induced tunnelling model (FIT). By calculating the distance 's' between two successive clusters (the distance between two active imines centres (=N+H-) of PANI) from the FIT model, we deduce that electron charge transfer is done by inter-chain hopping for the range [p = 40 to 60%] and by intra-chain hopping for p = 70 to 90%. Some insights about the contribution of the ionic charge transport for PANI concentrations in the interval 5% < p < 30% were obtained using impedance measurements at different frequencies. X-ray diffraction measurements, Fourier transform infrared spectroscopy and scanning electron microscopy were used to investigate the effect of PANI on the structure and morphology of composites.