CRITICAL BREAKDOWN FIELD OF ELECTROCHEMICALLY PRODUCED POLYPHENYLENE OXIDE-FILMS

The electrical breakdown of thin films of polyphenylene oxide electrochemically deposited on stainless steel plane substrates has been studied. First it was examined the dependence of the medium surrounding the dielectric and the electrodes (nature, hydrostatic pressure) on the breakdown voltage and on its statistical distribution. Between sphere and plane electrodes, it appears that even for pressurified gases, breakdown of the film is caused by the gas breakdown. We have analysed the discharges occurring at atmosphere pressure in the test cell. Breakdown of the film occurred when the electric field due to the charge deposited on its surface was about 230 V/mu-m. We have also studied self-healing capacitors with PPO as a dielectric, and determined the life-time of this material.