Thermally stimulated depolarization current and dielectric spectroscopy used to study dipolar relaxations and trap level distribution in PMMA polymer

Electronic Structure of Polymer Dielectrics: The Role of Chemical and Morphological Complexity

“…Because of the higher concentration and the higher conformational freedom associated with the OCOC groups, deep trap depths (of about 1 eV) are introduced in PMMA, which is close to the β relaxation of the OCO C group measured by the TSDC at 50 °C. 38 For PET and PBT, however, shallow trap depths were obtained. This is consistent with the results derived from SCLC spectroscopy (0.2−0.4 eV) 39 and TSC (0.33, 0.76 eV) 37 measurements in the case of PET.…”

“…Available experimental values are also provided, which are believed to be electron trap depths. 12,[37][38][39]58 In the case of amorphous PE and PP, our results indicate introduction of shallow hole and deep electron trap depths, which is consistent with the available experimental values. 12,39 While the former is caused by the conformational disorder in the polymer chains, the latter is due to the low physical density (0.85 g/cm 3 , as opposed to ≃1.1 g/cm 3 for the crystalline phase) of the amorphous phase that substantially increases interchain distances and thus reduces the hybridization of the antibonding orbitals discussed earlier.…”

Thermally stimulated depolarization current characteristic of EVA–conductive PPy composites

“…The resulting current is a function of temperature, and the recorded TSDC thermograms present several peaks, indicating that several processes are operative including mainly the depolarization of permanent dipoles and the release of charges from traps. 20,21 The data were taken by the average of three different samples.…”

Biaxially oriented silica–polypropylene nanocomposites for HVDC film capacitors: morphology-dielectric property relationships, and critical evaluation of the current progress and limitations

“…Thermally stimulated depolarization current (TSDC) Figure 9a presents the TSDC spectra of selected compounds along with a commercial capacitor BOPP film reference from 18,77 . The TSDC spectra comprise of a superposition of homo-and heterocharge components 80,81 : in principle, the homocharge component is associated with the de-trapping of space charge formed by (bipolar) charge injection from the electrodes 18,82 , while the heterocharge component is associated with dipolar species 83 , dissociation of ions 80 and, assuming that high electro-thermal stress was applied for sufficient time during the preceding poling step under high electric field, heterocharge which can be formed by slow migration of the injected homocharge towards the opposing electrode 84 . Thus, for non-polar polymers such as PP, the TSDC peak temperature and amplitude are mostly related to the depth and density of (occupied) traps.…”