International Journal of Science, Engineering and TechnologyAuthors: Sandeep K M, J S Ashwajeet, Raghavendra M N.
Abstract: In this study, polypyrrole/tungsten trioxide (PPy/WO₃) nanocomposites were synthesized by chemical oxidative polymerization and systematically analyzed for their frequency-dependent AC conductivity and dielectric properties. X-ray diffraction confirmed the successful integration of nanocrystalline WO₃ within the amorphous PPy matrix, with crystallite sizes between 61.9 and 74.5 nm. Dielectric measurements showed that increasing WO₃ content significantly enhanced both permittivity (ε′) and dielectric loss (ε″), particularly at low frequencies—an effect attributed to Maxwell–Wagner–Sillars interfacial polarization. AC conductivity increased monotonically with frequency, followed Jonscher’s universal power law (0.22 ≤ s ≤ 0.50), and rose from ~10⁻3 to 10⁻1 S·cm⁻¹ with frequency and optimal WO₃ loading, consistent with hopping and tunneling of localized charge carriers through percolative pathways. Electric modulus and Nyquist impedance analyses revealed pronounced non-Debye relaxation, a broad distribution of relaxation times, and strong composition dependence of bulk and interfacial resistances. Notably, an intermediate WO₃ content offered the best balance between enhanced interfacial polarization and the formation of continuous conducting networks. These results demonstrate that precise control of WO₃ loading enables effective tuning of polarization mechanisms, relaxation dynamics, and AC conduction in PPy, positioning PPy/WO₃ nanocomposites as promising candidates for frequency-tunable dielectric components, capacitive sensors, and compact energy storage devices.
DOI: http://doi.org/10.5281/zenodo.17722005
