Abstract. Radio-frequency conductivity measurements on ethylene glycol-water mixtures at 298, 308 and 323 K under a 1 MHz electrical field have been used to evaluate the semiconduction activation energy . Two mathematical expressions have been formulated to represent the temperature and concentration variations of the rf conductivity and to calculate the rf conductivity for a dipolar mixture like ethylene glycol-water in terms of the conductivities of its components. These relations can satisfactorily explain the observed experimental results. The dielectric relaxation time and the corresponding energy parameters (, and ) for the process of dipolar orientation have also been computed for the mixtures using rf conductivity data. Analysis of the evaluated values shows that the semiconduction activation energy and dielectric relaxation time for such liquid mixtures obey a simple mixing rule.

Print publication: Issue 7 (7 April 1999)
Received 31 March 1998, in final form 16 October 1998