Activation parameters of conjugated polyaniline electrolyte via dielectric relaxation technique

Abstract

The synthesis and relaxation mechanism of polyaniline electrolyte in form of thin film by oxidative polymerization in the presence of inorganic acid have been reported. The films have been characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, 2-point probe and UV-Vis absorption spectroscopy. The mechanism of electrical conductivity for the disordered system has been explained in terms of Mott’s variable-range hopping for the intrinsic conduction of the protonated long chain. The dielectric parameters including real part, imaginary part and loss tangent have been measured between the wavelength range 400 – 1100 nm. These have been employed in the determination of dielectric relaxation time τ which exhibits Arrhenius-like behaviour. Finally, the temperature dependent relaxation time which is a function of activation energy of dipole orientation otherwise known as Gibbs free energy ∆G^#, has been utilized in estimation of some thermodynamic parameters such as enthalpy ∆H^# and entropy ∆S^#. The SEM shows an aggregation of randomly oriented fibrous network of polyaniline on the surface of substrate. Fourier transform infrared confirms the acoustic vibrational modes of the long chain polymer.