Comparative analysis of isothermal decay of the surface potential of fluoroethylenepropylene electrets and of the sensitivity of electret microphones at elevated temperature
| Autor: | Heinz von Seggern, Marko Liebler, Gerhard M. Sessler, Andre Gerlach, Erhard Hirth, Bernd Scheufele |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Materials science Microphone Drop (liquid) Time constant General Physics and Astronomy 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Isothermal process lcsh:QC1-999 Computational physics 0103 physical sciences Electret Fluorocarbon Exponential decay 0210 nano-technology Sensitivity (electronics) lcsh:Physics |
| Zdroj: | AIP Advances, Vol 10, Iss 9, Pp 095313-095313-11 (2020) |
| ISSN: | 2158-3226 |
| Popis: | It is well known that fluorocarbon electrets, although thermally very stable, suffer a surface potential decay if exposed to high temperatures. This potential decay is of considerable interest in applications, for example, in the so-called prepolarized microphones. As a result, these devices suffer a loss in sensitivity approximately proportional to the decay of the electret surface potential. Since the potential and the related sensitivity losses are very slow at room temperature, a common approach in the literature is to perform accelerated isothermal depolarization experiments at elevated temperatures, and extrapolate the results to lower temperatures by assuming an Arrhenius-type behavior. In this paper, we investigate experimentally the potential decay of differently pre-annealed fluoroethylenepropylene electrets of different thicknesses, as well as the drop of sensitivity of commercially available measurement microphones from several manufacturers by the exposure to an ambient temperature of 95 °C for up to three years. Until now, no other reports compare electret and microphone decays over such a long period. The experimental data presented here could not be fitted with only one exponential decay function over the whole time-span investigated. However, assuming two or more discharge processes results in a good agreement between measurement and model functions. The time constants of these decay processes are specified in the text. |
| Databáze: | OpenAIRE |
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