Nonlinear conduction in aromatic polyurea thin films and its influence on dielectric applications over a broad temperature range

We investigate nonlinear conduction in aromatic polyurea thin films and its influence on the dielectric applications over a broad temperature range. The experimental data indicate that several high field conduction mechanisms coexist in the polymer films and one conduction mechanism may dominate over the others depending on different temperatures. The results also reveal that owing to the non-linear increase of the conduction loss with field, the dielectric loss at high field can be many orders of magnitude larger than that at low field. Therefore, besides the electrical breakdown strength, the conduction loss at high field and their temperature dependence behavior are other key factors in developing polymer dielectric materials for high energy density dielectric applications over a broad temperature range.