Frequency-dependent conductivity and dielectric permittivity of polyaniline/CeO2 composites

The PANI/CeO2 composites were synthesized using in situ deposition technique by placing fine graded CeO2 in polymerization mixture of aniline. This is the single step polymerization process for the direct synthesis of emeraldine salt phase of polymer. Low frequency dielectric studies were carried out on pressed pellets of PANI/CeO2 with various concentrations of cerium oxide (10, 20, 30, 40, and 50 wt % of CeO2 in PANI). The results are interpreted in terms of polarons and bipolarons, which are responsible for the dielectric relaxation mechanism and frequency dependence of conductivity. It is found that a.c. measurements at room temperature may well serve as a parallel way to the time consuming d.c. conductivity versus temperature technique, to detect the thermal degradation of the transport properties in conducting polymers. It is observed that the charge motion via creation/annihilation of polarons and bipolarons increases as the weight percentage of the composite is increased.