Electrical transport properties and thermoelectric power studies of polyaniline–CaTiO 3 composites

In situ polymerization of aniline was carried out with calcium titanate, in order to synthesize polyaniline/calcium titanate composites by the chemical oxidation in the presence of ammonium persulfate as an oxidizing agent. To study the effect of calcium titanate on the properties of polyaniline (PANI), PANI/calcium titanate (CaTiO 3 ) composites were synthesized with different weight percentages (15, 25, and 35 wt %) of calcium titanate. The structural and morphological analysis was carried out by XRD and SEM, while their electrical properties were studied by temperature-dependent dc conductivity. Thermal properties were also studied, and seebeck coefficient and thermoelectric power studies demonstrated a strong dependence on the weight percentage of calcium titanate in the pure polyaniline. The charge transport mechanism was investigated by temperature-dependent dc electrical conductivity measurements in the temperature range of 303–483 K. Further, an increase in dc conductivity was found on the inclusion of calcium titanate at all temperatures, and the most probable model of charge transport was found to be three-dimensional variable range hopping (3D-VRH) for pure polyaniline while switching to one-dimensional variable range hopping (1D-VRH) in the case of its composites with calcium titanate that has been interpreted in terms of linearization and straightening of polymer chains. The calcium titanate content not only influenced the electrical conductivity but the thermoelectric properties of the resulting composites as well. Graphical abstract