The electret nehavior of poly(vinylidene/chlorotrifluoethy-lene) (P(VDF/CTFE)) 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 heat pulse technology, the electret characters of the copolymer P(VDF/CTFE), polymerized from vinylidenefluoride (VDF) and chlorotrifluoroethylene (CTFE), have been first studied. The result points out: the space charge storage capability of P(VDF/CTFE) was significantly improved than that of PVDF. P(VDF/CTFE) was a polar material, namely, there exit both dipoles and space charges in the material. Moreover the space charge storage ability between positively and negatively corona charged samples has been compared; and the geometric distribution of traps was studied. Finally, the shift of mean charge depth at different charging temperatures has been investigated.