Charging temperature effect for corona charged Teflon FEP electret

The effect of charging temperature on charge storage of corona charged Teflon FEP (fluoroethylene propylene) electret is investigated. When the sample is negatively charged at elevated temperatures, a nonuniform charge distribution with the charge concentration in the near-surface that is greater than in the bulk is confirmed with the laser-induced pressure pulse method. By contrast, a uniform charge distribution throughout the bulk of the material is attainable so long as the sample is positively corona charged above 90 degrees C. According to the charge distribution and the trap structure, analysis shows that the charging temperature plays an important role in the charge stability for the Teflon FEP electret.<>