Electrical characterization of PEN films using TSDC and PEA measurements

Thermo-stimulated depolarization current (TSDC) measurements have been performed on poly(ethylene naphthalene 2,6-dicarboxylate) (PEN), an aromatic polyester. The aim is to develop the understanding of trapping mechanisms at play in this material, and particularly to understand the effect of temperature. Experimental results of TSDC are interpreted with the help of space charge measurements using the pulsed electroacoustic method (PEA) on PEN samples. For TSDC measurements, samples were polarized at temperatures of 130°C and 170°C. In both cases, the sub-glass transition and the glass transition relaxations are observed. However, in the case of a polarization temperature of 170°C, one more TSDC peak, so-called ρ-peak is observed at temperatures above the glass transition. From space charge results, it is shown that the ρ-peak has not a dipolar origin; it has been associated to charge detrapping in the material.