Photostimulated discharge in electret polymers: An alternative approach for investigating deep traps

Axel Mellinger, Francisco Camacho González, Reimund Gerhard-Multhaupt

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

The stability of space charge in electrets such as polytetrafluoroethylene (PTFE), polyethylene terephthalate (PETP) and polypropylene (PP) under ultraviolet irradiation has been investigated using photostimulated discharge spectroscopy. While only weak discharge currents were observed in PTFE coated with semitransparent gold electrodes, up to 15 pA/cm2 were found in PETP around the UV absorption edge near 310 nm. Space charge profiles obtained with the piezoelectrically generated pressure step method indicate that near-surface charges were almost completely removed. In PP foam, recent findings of a UV-reduced d33 coefficient were confirmed for exposure times of up to 3.5 h, and a discharge peak at 200 nm could be assigned to the charges stored on the surfaces of the voids. The unique morphology and the (quasi-) piezoelectric properties of cellular PP make it a role model for the future investigation of charge storage in electrets.

Original languageEnglish
Pages (from-to)218-226
Number of pages9
JournalIEEE Transactions on Dielectrics and Electrical Insulation
Volume11
Issue number2
DOIs
StatePublished - Apr 2004

Keywords

  • Electret polymers
  • Photostimulated discharge
  • Piezoelectric coefficient
  • Piezoelectric resonances
  • Piezoelectricity
  • Polyethylene terephthalate
  • Polypropylene
  • Polytetrafluoroethylene
  • Thickness extension resonance
  • UV spectroscopy
  • Voided polymer

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