Piezoelectricity of Uniaxially Oriented Polyvinylidene Fluoride

Piezoelectric polyvinylidene fluoride (PVDF) shows promise as a material for ultrasonic a pplications. The development of piezoelectric transducers requires the knowledge of their dielectric, elastic and piezoelectric properties. I nvestigations of the material parameters are usually carried out by exciting piezoelectric resonances.However, piezoelectric resonances of PVDF films, showing high mechanical and dielectric losses,cannot be evaluated by standard methods. The material parameters were determined by means of network analysis. Additionally, quasistatic measurements of the elastic and piezoelectric p roperties were carried out. The observed frequency dependence of the elastic and piezoelectric constants is discussed. Using an interferometric method the Poisson ratios p3,and ~3~ are measured. These data are used to determine a complete set of elastic constants with the exception of the shear coefficients. The quasistatically measured elastic and piezoelectric data enabled us to calculate the i mportant piezoelectric constantse3,ande,,that could not be measured directly. The experimental results are compared with t heoretical models.