Electrical characterization of PEN films using TSDC and PEA measurements

Abstract

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, socalled 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.

Effect of Cumyl Alcohol in Multilayer Dielectric on Space Charge Build Up

“…For the sample with cumyl alcohol it is 10 -13 S/m as obtained for a field of 30 kV/mm. Considering these values and value of the conductivity for PEN of 2.6 x 10 -17 S/m [11], it can be anticipated that the field is contained essentially in the PEN layers, and is very high (300 kV/mm or more) even for the unsoaked LDPE. This is consistent with the large interface charge found at the PEN/LDPE interface.…”

“…The space charges found in this configuration is rather complex and may have several origins: i) orientation polarisation of PEN, which is a polar material [11]; ii) charges migrating into LDPE and being blocked at the interface with PEN; iii) charges injected in the PEN layer; iv) interface charge build-up due to the difference in permittivity of the two materials. Finally, because of mismatch of acoustic properties of the materials, multiple reflection in the PEN layers may produce apparent acoustic signal in the bulk.…”

Rate Theory and Relaxation Map Analysis of Iodine-Doped Poly(Ethyl Methacrylate) composite films using Thermally Stimulated Depolarization Current-Thermal Sampling (TSDC-TS) Technique

“…It is a powerful technique because of its low equivalent frequency ~ 10 -3 Hz and its ability to decompose complicated dielectric relaxation behaviour. Relaxation behaviour in polymeric materials is usually interpreted in terms of relaxation time distribution, so that TSDC global spectrum analysis is carried out by fitting the parameter associated to symmetry and shape of relaxation times distribution that characterize these patterns [8][9][10]. To decompose complex TSDC spectra experimentally and hence, relaxation times distribution, thermal sampling (TS) method has been used, demonstrating the ability of decomposing complex TSDC spectrum into elementary peaks with narrow range of distribution of relaxations [11][12][13][14][15].…”