The poling process and distribution of polarization in double layered P(VDF/TrFE) and Teflon FEP films system

The novel piezoelectric material P(VDF-TrFE) were prepared on Teflon FEP films by casting from solution. These double layered films were charged by corona method. Surface potential decay, thermal pulse response curves, TSD current spectra and piezoelectric coefficient measurements were also used to analysis the space and dipole charges inside the films. The profile of polarization were found to be different in Teflon top-layered and P(VDF/TrFE) top-layered films. The distribution of polarization along the film thickness in polar polymer can be controlled by introducing a high stable electret layer.