The electret behavior of poly(vinylidenefluoride/chlorotrifluorethylene) film

By positively and negatively corona charging at room and elevated temperatures, measurements of surface potential decay, thermally stimulated discharge (TSD) current spectra in combination with the heat pulse technology, the electret character of the copolymer P(VDF/CTFE) film, polymerized from vinylidenefluoride (VDF) and chlorotrifluorethylene (CTFE), has been studied. The space charge storage capability of P(VDF/CTFE) is significantly greater than that of PVDF. P(VDF/CTFE) is a polar material, i.e. it contains both dipoles and space charges in the material. Moreover the space charge storage ability of positively and negatively corona charged samples has been compared, and the geometric distribution of traps has been studied. Finally, the shift of mean charge depth with charging temperature has been investigated.