POLY 137 |
| Metallized polymer film capacitors with thin layers of deposited electrodes exhibit the unique function of 'self-healing' or 'clearing' upon the application of voltage. These self-healing events electrically isolate the flawed sites from the rest of the device; while there is a small loss of capacitance due to each one of these localized breakdown or energy discharge events, the capacitor will continue to operate, showing enhanced tolerance to increasing applied voltage till the occurrence of catastrophic electrical breakdown. This paper reports on the self-healing behavior of a high temperature, amorphous cardo-type polyester film spin-coated on a metallized substrate. The I-V characteristics of the M-I-M (Metal-Insulator-Metal) device were monitored in steps, with sequential increase in the maximum dc voltage that was applied across the electrodes. I-V scans indicated a hierarchical pattern of clearing of defects, characterized by surges in the observed current, as a function of the applied voltage. While electrical self-healing was demonstrated during the breakdown (I-V) experiments, indirect evidence for 'clearing' as well as for the catastrophic failure of the device was provided by the measurements of device capacitance and dielectric loss factor. The signature of self-healing characteristics in metallized thin insulating films enhancing operational voltage sustainability of the capacitor device as a consequence of 'clearing' was evident from these experiments. |
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General Papers: Functional Materials
6:00 PM-8:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Polymer Chemistry |