Measurement of all the elastic and dielectric constants of poled PVDF films

As opposed to conventional piezoceramics, PVDF is a piezoelectric material, in polymer form. However, its properties are not well characterized due to the availability of poled PVDF only as a thin film. In the design of piezoelectric devices, properties such as all the components of the elastic stiffness tensor, dielectric tensor, and the electromechanical coupling tensor are needed. Poled PVDF is of mm2 symmetry. The frequency dependences of all nine complex elastic constants as well as the three complex dielectric constants were measured using a thin film and stacked, cubical samples of PVDF film. The elastic constants C^D₄₄ and C^D₅₅ as well as the dielectric constant ε^T₁₁ and ε^T₂₂ reported here are new. Ultrasonic measurements and an impedance analyzer were used to obtain the measured data.