The breakdown threshold of dielectric barrier discharges in piezoelectric polymer foams

The piezoelectric activity of charged cellular foams (so-called ferroelectrets) is compared against simulations based on a multi-layer electromechanical model and Townsend´s model of Paschen breakdown, with the distribution of void heights determined from scanning electron micrographs. While the calculated space charge hysteresis curves are in good agreement with experimental data, the onset of piezoelectric activity is observed at significantly higher electric fields than predicted by Paschen´s law. In addition, the model suggests that optimized charging should be possible by varying the gas pressure while the charging field is applied.