Dielectric Spectroscopy of Pani-CaTiO3 Composites

Abstract

The stability, processability and electrical and optical properties of polyaniline (PANI) have led to its being investigated for use in a wide variety of applications. Much of the initial work centered on the wide range of conductivity that can be achieved, covering some 20 orders of magnitude. Although (PANI) can indeed form highly conductive materials upon doping, the long-term stability of these materials may be a problem. It is probable that it will be the semi conductive and photoconductive properties of this polymer that will prove more useful in nature. In the present work, synthesis of polyaniline (PANI) is carried out by chemical oxidation method by using various percentages (10, 20, 30, 40 and 50 wt%) of CaTiO 3 in PANI by in situ polymerization. The composites are characterized by using various techniques such as XRD, IR and SEM spectroscopy. From these studies it is observed that CaTiO 3 is homogeneously distributed in PANI. The dielectric constant and dielectric tangent loss are studied by sandwiching the pellets of these composites between the silver electrodes. It is observed from these studies of the dielectric constant that, it decreases exponentially with frequency. From the studies of dielectric tangent loss, it is observed that PANI-CaTiO3 decreases as a function of frequency. Both PANI and its composites exhibit the small value of dielectric loss at higher frequency. The AC conductivity is studied in the frequency range from 10 2 –10 7 Hz. From these studies it is found that, AC conductivity remain constant at low frequency and increase rapidly at higher frequency, which is characteristic behaviour of disordered materials.