The dielectric properties and charge transport mechanism of π-conjugated segments decorated with intrinsic conducting polymer

In this study, flexible solid polymeric composite (FSPC) films comprised the poly-blend of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) decorated with different dosing of the intrinsic conducting polymer (ICP), polyaniline (PANI) have been fabricated via solution casting. FESEM was carried out to monitor the morphology and dispersion of PANI in the FSPC films and the roughness of the films were further studied using SPIP imaging software. The electrical ac conductivity, dielectric constant, loss tangent and electric modulus of the films have been investigated using BDS over a wide frequency range of 0.1 Hz to 10 MHz and a temperature range of 0-100 degrees C. The high dielectric constant was observed to be 1.69 x 10(3) at 1 kHz and 70.1 at 10 MHz for 20% of PANI at room temperature. The relaxation peaks in the loss tangent spectrum were observed for the polymer composite films corresponding to the segmental motion of the polymers and therefore the chain dynamics of the polymers are faster in the FSPC's films. Upon increasing the fraction of PANI, the relaxation peaks are observed in the tan delta spectra, which are associated with the phenomena of trapped electric charge appearing at the polymers interface. The enhancement in conductivity from 10(-7) S cm(-1) to 10(-4) S cm(-1) (1000 times) was observed, which follows the universal power law of frequency. The frequency assisted ac electrical conductivity for various temperatures was used to infer the charge transfer mechanism in the composite with the help of different models. These results support the hopping of the positive charged state of polarons and bipolarons.