Orientation effects on dielectric and piezoelectric properties of polyvinylidene fluoride films

The dielectric constant and loss of polyvinylidene fluoride (PVF∼) films is a strong function of the manufacturing conditions. Degree of orientation and processing temperatures affect the crystalline and mechanical properties of the resulting films. Piezoelectric activity for a given set of poling conditions is also dependent upon the type of film. Dielectric, structural and piezoelectric data are presented for unoriented, uniaxially oriented and biaxially oriented films prepared by a variety of techniques. Theoretical models are discussed which account for the experimental observations.