Performance of Piezoelectrets Made of Non-porous Polytetrafluoroethylene and Fluoroethylenepropylene Layers

摘要

The thermal stability of piezoelectric d_33 coefficients and charge dynamics in the piezoelectret films with tailored microstructure, made of non-porous polytetrafluoroethylene (PTFE) and fluoroethylenepropylene (FEP) layers, are investigated by the measurements of the isothermal decay of piezoelectric dn coefficients at elevated temperatures and the analysis of thermally stimulated discharge (TSD) current spectra in short circuit, respectively. The results show that the quasi-static piezoelectric c/33 coefficient up to 300 pC/N is achieved and its Young's modulus is about 0.28 MPa. The c/33 values in the present studied films show improved thermal stability compared with the films without regular microstructure. The drift path for the most of detrapped charges in the films is through the solid dielectric layer.