Enhancement of Electret Retention

Electrets are polymeric materials which can retain the electrostatic charge for long time. They have many applications such as microphones, filters and energy harvesters. 

High charge retention is required to enhance their use in the aforementioned areas. However, it is known that electret exposure in organic solvents or high relative humidity could detrimentally affect charge retention. A possible mechanism that can attribute to this behaviour is the increase of charge mobility due to the vapour condensation on the electret which leads to the swelling of the polymer.

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We have setup a system to charge the polymeric materials and monitor their discharge online (see Fig.). We study the charging mechanism which affects the charge retention properties due to the different natures of charge carriers. Electrets are charged with various mechanisms and a possible link among the charging mechanism, filter properties, and electret performance is investigated.
Prof. Dr. Jing Wang

Prof. Dr. Jing Wang
PI Nanoparticle Analysis

Phone: +41 58 765 6115

References

Gao, H.; He, W.; Zhao, Y. B.; Opris, D. M.; Xu, G.; Wang, J. Electret mechanisms and kinetics of electrospun nanofiber membranes and lifetime in filtration applications in comparison with corona-charged membranes. J. Membr. Sci. 2020, 600, 117879 (11 pp.). https://doi.org/10.1016/j.memsci.2020.117879
Detailed Record
He, W.; Zhao, Y. B.; Jiang, F.; Guo, Y.; Gao, H.; Liu, J.; Wang, J. Filtration performance and charge degradation during particle loading and reusability of charged PTFE needle felt filters. Sep. Purif. Technol. 2020, 233, 116003 (8 pp.). https://doi.org/10.1016/j.seppur.2019.116003
Detailed Record
Sun, Z.; Yue, Y.; He, W.; Jiang, F.; Lin, C. H.; Pui, D. Y. H.; Liang, Y.; Wang, J. The antibacterial performance of positively charged and chitosan dipped air filter media. Build. Environ. 2020, 180, 107020 (10 pp.). https://doi.org/10.1016/j.buildenv.2020.107020
Detailed Record
Chen, S. C.; Wang, J.; Bahk, Y. K.; Fissan, H.; Pui, D. Y. H. Carbon nanotube penetration through fiberglass and electret respirator filter and nuclepore filter media: experiments and models. Aerosol Sci. Technol. 2014, 48 (10), 997-1008. https://doi.org/10.1080/02786826.2014.954028
Detailed Record