Piezoelectricity of PVDF/PUE, PVDF/PMMA and PVDF/(PMMA+BaTiO3 ) laminates

The author suggests the preparation of piezoelectric laminates using PVDF (polyvinylidene fluoride) polymer film (a), polyester urethane elastomer (PUE) film (b), PMMA (polymethyl methacrylate) film (c), and (PMMA+BaTiO₃) composite film (d). Systems of three-layered structure of (aba), (aca), and (ada) have been made, and then conventional electrets based on these laminates have been prepared. The modification of internal layers in the systems leads to a change in their dielectric properties and also in the mechanical parameters which determine the piezoelectricity. The origins of piezoelectricity in these systems have been considered on the basis of TSD thermograms. It is shown that the initial piezoelectric constant d₃₃ is the highest for the PVDF-PMMA/BaTiO₃ system but the better piezoelectric stability can be obtained in electretized PVDF-PUE-PVDF laminate