Polyaniline–calcium titanate perovskite hybrid composites: Structural, morphological, dielectric and electric modulus analysis

This paper reports hybrid composites based on polyaniline (PANI) and calcium titanate (CaTiO ₃ ) perovskite as a nanofiller synthesized by in-situ polymerization technique. Their structure and morphology were investigated by X-ray diffraction analysis and scanning electron microscopy. The XRD analysis shows that the addition of CaTiO ₃ in polyaniline reduced the amorphous structure of polyaniline transforming it into semi-crystalline nature, which agrees well with the higher conductivity. Scanning electron microscopy of composites showed a more compact and homogenous structure with uniform distribution of CaTiO ₃ in the polymer matrix. Dielectric parameters such as dielectric constant, loss factor, and dielectric loss, real and imaginary parts of electric modulus were measured and evaluated as a function of frequency and temperature as well. The variation of dielectric properties and ac conductivity reveals that the dispersion is due to the Maxwell-Wagner type of interfacial polarization. The observed ac conductivity behavior of polyaniline in the presence of calcium titanate was discussed in the framework of Jonscher’s power law. The result showed that ac conductivity increases with the rise of the frequency of applied field and temperature analogous to the semiconducting behavior of composites. Temperature-dependent behavior of frequency exponent seems to obey correlated barrier hopping conduction mechanism. The relaxation behavior of the synthesized samples was analyzed by the electric field modulus and was found to decrease with temperature and CaTiO ₃ content and increase with frequency.