Thermally stimulated discharge current studies of acrylic-acid-doped polystyrene films

Thermally stimulated discharge currents in thin cylindrical films (30 μm thick) of polystyrene either undoped or doped with acrylic acid were measured under various polarizing conditions. It was found that the undoped samples give rise to a single peak around 105 °C which is due to the release of space charges present in the material. In the doped samples this peak is shifted to 58 °C and another peak appears at around 150 °C. The peak at the lower temperature is due to the superposition of the dipolar peak of the dopant and the space-charge-limited peak of the matrix, whereas the peak at the higher temperature has been attributed to the space charge of the material retained in the double bonds of the dopant, as a result of interaction between the dopant and the matrix.