Measurements of spatial charge in nonhomogeneous dielectrics with nanofillers

The subject of the research were non-homogeneous PVDF based dielectrics filled with nanoparticles. The aim of the study was to investigate the influence of polarization conditions on the value of accumulated space charge and its relaxation time (lifetime). Measurements were carried for various types of electrets obtained by contact polarization, with varying parameters (voltage value and polarity, process duration, temperature). Thermally stimulated depolarization current method (TSDC) has been used to determine space charge of dielectrics. Based on the measured j(T) characteristics, the activation energies and relaxation time of the electrical charge were calculated. Significant influence of the material structure (type of nanocomposite) and polarization conditions, especially voltage and temperature, on the determined space charge was observed.