Temperature behavior of electric relaxational effects due to ionic conductivity in liquid lactones

Abstract

This paper concerns the studies of temperature and frequency behavior of the complex impedance, electric modulus, and electric conductivity due to an ionic current in liquid γ-butyrolactone (GBL) and γ-valerolactone (GVL). The frequency of the applied electric stimulus (500Hz to 5MHz) corresponds to the static dielectric regime of the lactones. The studies were performed in the temperature range of 263K to 313 K. It was shown that in the static dielectric case, the dc ionic conductivity (σ DC ) and the static dielectric permittivity (ε s ) determine the relaxational behavior of the impedance (Z*) and the electric modulus (M*) of the molecular liquids and both spectra are of the Debye-type characterized by the same conductivity relaxation time (τ σ ). Both σ DC and τ σ of GBL and GVL fairly well fulfill an Arrhenius temperature dependence with very similar values of the thermal activation energy E σDC ~ Eτ σ ~ 25 kJ · mol -1 . The temperature dependence of the static dielectric permittivity and its temperature derivative is analyzed and interpreted in terms of the dipolar aggregation in the studied lactones. © Springer Science+Business Media, LLC 2012.