Electric-field profiles in corona- or electron-beam-charged andthermally treated Teflon PTFE, FEP, and PFA films

摘要

Charge spreading in three different types of Teflon electrets wasstudied by means of piezoelectrically generated pressure steps, FEP andPFA samples corona-charged at room temperature usually exhibited only asurface charge layer. Uniform charge spreading throughout the bulk wasfound in FEP charged at or heated to high temperatures. Charge spreadingwas much less prominent in PFA because of a smaller retrappingefficiency. In PTFE (polytetrafluorethylene), charges from the surfaceand the rear electrode were injected into the bulk during charging atany temperature. Electron-beam-deposited charge layers broadenedsignificantly upon heating