Term: electret
https://doi.org/10.1351/goldbook.08795

Definition:
Dielectric material with a permanent or quasi-permanent electric dipole.

Notes:
1) A real-charge electret is obtained by the charge carrier injection onto the surface or into a parent dielectric material. It may contain either positive or negative excess charges or both, which must be trapped so that a good insulating parent dielectric material such as a fluoropolymer must be used.
2) An oriented-dipole electret is obtained by poling a parent dielectric material with dipolar groups at a temperature above the glass transition temperature \(T_{\rm{g}}\), and eventual next stabilization of the structure by cooling the electret down below \(T_{\rm{g}}\) or by crosslinking.
3) Electrets are electric equivalents of magnets; electric magnets. Some oriented-dipole electrets are ferroelectric polymers and piezoelectric polymers. Quartz is an example of the natural electret.

Link: 
Related Term: dielectric material (http://doi.org/10.1351/goldbook.08790).
Related Term: charge carrier (http://doi.org/10.1351/goldbook.08775).
Related Term: dielectric material (http://doi.org/10.1351/goldbook.08790).
Related Term: poling (http://doi.org/10.1351/goldbook.08857).

Source: PAC, 2022, 94, 15. 'Glossary of terms relating to electronic, photonic and magnetic properties of polymers (IUPAC Recommendations 2021)' on page 25 (https://doi.org/10.1515/pac-2020-0501)

Citation: 'electret' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.08795

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