Influence of charge injection on the formation of remanent polarization in P(VDF-TrFE) copolymers

The influence of charge injection on the formation of remanent polarization of P(VDF-TrFE) copolymers was studied by inserting an insulating barrier between the metal electrodes and the P(VDF-TrFE) copolymer during the poling process. The resulting remanent polarization is significantly smaller than that of identically poled samples for the same field strength and time duration, but with directly contacting metal electrodes. This shows that the orientation of the dipoles alone is not a sufficient condition for the formation of remanent polarization in PVDF and its copolymers. The experiments indicate that the stabilization of the polarization is mediated by charge injection and charge trapping at polarized crystallite surfaces