Electric modulus based relaxation dynamics, ac-conductivity and I–V characteristics in PTh/[Co(EDTA)NH₃Cl] H₂O nanocomposite prepared by chemical oxidation method

A thread like nanocomposite material based on PTh/[Co(EDTA)NH₃Cl] H₂O has been successfully prepared by in-situ chemical oxidative polymerization for the investigation of dielectric properties. XRD reflects its crystalline nature with a particle size of 40 nm. TEM clearly showed a two phase system consisting of [Co(EDTA)NH₃Cl] H₂O (photoadduct) particles immersed in PTh threads. Thermogravimetry exhibits an increase in its thermal stability than pristine PTh. Enhanced dielectric constant of around (ε′ = 500 at 10⁴ Hz) has been observed than many other systems reported recently. This is of conducive value for energy storage and has been attributed to (1) Maxwell–Wagner interfacial polarization and (2) increased aspect ratio due to the thread like structure. Moreover, the losses observed in the material are dominated by dc-conduction as has been confirmed by the electric modulus formalism. Frequency dependent conductivity (σ_ac) has been found to be of higher value (~10⁸ S/m), which saturates at high frequencies. Electric modulus formalism shows a change over from dc- to ac-conduction. I–V characteristics showed a typical ohmic behavior of nanocomposite with a resistance of 2.7 × 10⁴ Ω, thereby excluding RS/PF or SCLC conduction mechanisms. Such a material can provide absorption and reflection to EMI shielding.