Performances of regular structure piezoelectrets made by template

摘要

Preparation of piezoelectret films with regular void structure by using a rigid template method is described in this paper. Laminated piezoelectret films with regular void structure are prepared by using porous polytetrafluoroethylene (PTFE) and fluoroethylenepropylene (FEP). The Young's modulus of the laminated regular structure films is determined by dielectric resonance spectra. The quasi-static piezoelectric coefficient d₃₃ is measured by direct piezoelectric effect. The thermal stability of the piezoelectric d₃₃ coefficients is characterized by measuring the decay of d₃₃ at elevated temperatures. The charge dynamics in such regular structure piezoelectrets is investigated by analyzing the thermally stimulated discharge current spectrum in short circuit. The results indicate that the Young's modulus of five-layer structure piezoelectret films is about 0.48 MPa. The quasi-static piezoelectric coefficient d₃₃ is not only up to 500 pC/N, but also shows good thermal stability. The de-trap charges mainly migrate along the surface of holes and ultimately recombinate with opposite charges which deposited on the same hole's relative hole wall.