Polarization of VDF-TrFE copolymer films at elevated temperature

The buildup of the polarization of VDF-TrFE copolymer films, at room temperature and after various thermal treatments, is studied using the PWP (pressure wave propagation) method. This method allows the nondestructive measurement of the homogeneity of the piezoelectric coefficient. The samples are polarized at 100 degrees C, and the influence of different thermal treatments before polarization, and of the insulator-electrode interfaces, are analyzed. The behavior of the copolymer is compared to that described previously for poling experiments made at room temperature. The effect of electron injection at the cathode by nonblocking electrodes is clearly shown.<
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