Determination of Lorenz number of composite films based on copper chloride(II) in polyvinyl alcohol matrix

Abstract

The electrical and thermal conductivities as well as Lorenz number of polyvinyl alcohol (PVA) composites have been investigated at different concentrations of the copper chloride II (0, 1, 3, 5, 7 and 12 wt-%). The powder of copper chloride II (CuCl2) was casted with the PVA polymer1. The electrical conductivity was measured by using the impedance technique, and it was studied as functions of the CuCl2 concentrations, applied frequency range of 100–7000 kHz, and temperature range of 30–100 °C. The activation energy ( Ea) was also determined for all the studied samples at applied frequency of 1000 kHz. It was found that the Ea decreased with increasing the CuCl2 concentration. Moreover, the thermal conductivity of the samples was studied as functions of the CuCl2 concentration and temperature. It was found that the thermal conductivity increased with increasing the CuCl2 concentrations and temperature. Using the measured values of the thermal and electrical conductivities of the studied samples, the relationship between the Lorenz number ( L) of the PVA and CuCl2 concentrations with constant temperature was also studied based on the Wiedemann–Franz law. The results showed that the L number increased with CuCl2 concentrations increase at constant temperature.