POLARIZATION OF VDF-TRFE COPOLYMER FILMS AT ELEVATED-TEMPERATURE

The buildup of the polarization of VDF-TrFE copolymer films, at room t emperature and after various thermal treatments, has been studied usin g the PWP method. This method allows the nondestructive measurement of the homogeneity of the piezoelectric coefficient. In this paper, we h ave polarized the samples at 100-degrees-C and analyzed the influence of different thermal treatments before polarization, and of the insula tor-electrode interfaces. The behavior of the copolymer is compared to that described previously for poling experiments made at room tempera ture. The effect of electron injection at the cathode by non-blocking electrodes is clearly proved.