Dielectric and electrical behaviour over the static permittivity frequency regime, the refractive indices and viscosities of PC-PEG binary mixtures

The complex permittivity, alternating current electrical conductivity, electric modulus and the impedance dispersion over the frequency range from 20 Hz to 1 MHz for the propylene carbonate (PC) and poly(ethylene glycol) (PEG; molecular weight 200 g mol(-1)) mixtures spanning the entire mixing range have been investigated. The Nyquist plots of electric modulus and impedance for these polar liquid mixtures exhibit the Debye-type dispersion corresponding to the conductivity and electric double layers relaxation processes, respectively. The values of static permittivity, dc electrical conductivity, refractive index and viscosity of the PC-PEG mixtures in the temperature range 5-55 degrees C have been reported. The excess properties of static permittivity, refractive index, and viscosity confirm the hydrogen-bond interactions between the PC and PEG molecules in their mixtures. The temperature dependent dc conductivity and viscosity of the PC-PEG mixtures obey the Arrhenius behaviour, and the activation energies of the mixtures decrease with an increase of PC concentration. The Stokes-Einstein relation for the conductivity in viscous media holds only for the PC-rich of PC-PEG mixtures. (C) 2018 Elsevier B.V. All rights reserved.