Comparative analysis of isothermal decay of the surface potential of fluoroethylenepropylene electrets and of the sensitivity of electret microphones at elevated temperature
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...
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| Format: | Article |
| Language: | English |
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AIP Publishing LLC
2020-09-01
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| Series: | AIP Advances |
| Online Access: | http://dx.doi.org/10.1063/5.0016219 |
| _version_ | 1818049192520581120 |
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| author | André Gerlach Marko Liebler Gerhard M. Sessler Heinz von Seggern Bernd Scheufele Erhard Hirth |
| author_facet | André Gerlach Marko Liebler Gerhard M. Sessler Heinz von Seggern Bernd Scheufele Erhard Hirth |
| author_sort | André Gerlach |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-12-10T10:33:40Z |
| format | Article |
| id | doaj.art-820ae0025c5141fd9d94bbafd42417b9 |
| institution | Directory Open Access Journal |
| issn | 2158-3226 |
| language | English |
| last_indexed | 2024-12-10T10:33:40Z |
| publishDate | 2020-09-01 |
| publisher | AIP Publishing LLC |
| record_format | Article |
| series | AIP Advances |
| spelling | doaj.art-820ae0025c5141fd9d94bbafd42417b92022-12-22T01:52:30ZengAIP Publishing LLCAIP Advances2158-32262020-09-01109095313095313-1110.1063/5.0016219Comparative analysis of isothermal decay of the surface potential of fluoroethylenepropylene electrets and of the sensitivity of electret microphones at elevated temperatureAndré Gerlach0Marko Liebler1Gerhard M. Sessler2Heinz von Seggern3Bernd Scheufele4Erhard Hirth5Corporate Sector Research and Advance Engineering, Robert Bosch GmbH, Robert-Bosch-Campus 1, 71272 Renningen, GermanyCorporate Sector Research and Advance Engineering, Robert Bosch GmbH, Robert-Bosch-Campus 1, 71272 Renningen, GermanyInstitute for Telecommunications Technology, Darmstadt University of Technology, Merckstrasse 25, 64283 Darmstadt, GermanyDepartment of Materials and Earth Sciences, Darmstadt University of Technology, Merckstrasse 25, 64283 Darmstadt, GermanyCorporate Sector Research and Advance Engineering, Robert Bosch GmbH, Robert-Bosch-Campus 1, 71272 Renningen, GermanyCorporate Sector Research and Advance Engineering, Robert Bosch GmbH, Robert-Bosch-Campus 1, 71272 Renningen, GermanyIt 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.http://dx.doi.org/10.1063/5.0016219 |
| spellingShingle | André Gerlach Marko Liebler Gerhard M. Sessler Heinz von Seggern Bernd Scheufele Erhard Hirth Comparative analysis of isothermal decay of the surface potential of fluoroethylenepropylene electrets and of the sensitivity of electret microphones at elevated temperature AIP Advances |
| title | Comparative analysis of isothermal decay of the surface potential of fluoroethylenepropylene electrets and of the sensitivity of electret microphones at elevated temperature |
| title_full | Comparative analysis of isothermal decay of the surface potential of fluoroethylenepropylene electrets and of the sensitivity of electret microphones at elevated temperature |
| title_fullStr | Comparative analysis of isothermal decay of the surface potential of fluoroethylenepropylene electrets and of the sensitivity of electret microphones at elevated temperature |
| title_full_unstemmed | Comparative analysis of isothermal decay of the surface potential of fluoroethylenepropylene electrets and of the sensitivity of electret microphones at elevated temperature |
| title_short | Comparative analysis of isothermal decay of the surface potential of fluoroethylenepropylene electrets and of the sensitivity of electret microphones at elevated temperature |
| title_sort | comparative analysis of isothermal decay of the surface potential of fluoroethylenepropylene electrets and of the sensitivity of electret microphones at elevated temperature |
| url | http://dx.doi.org/10.1063/5.0016219 |
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