Material characterization of thin film piezoelectric polymers

摘要

The paper describes an experimental program developed to characterize the material properties of thin film piezoelectric polymers PVF{sub}2, a co-polymer of PVDF (polyvinylidene fluoride). These unidirectional materials have been used as activeelements in composite devices for noise suppression and position control. Static and dynamic test results presented in the paper indicate that the mechanical response of PVF{sub}2 thin films at room temperature is time-dependent. The creep rates tend toaccelerate at elevated temperatures. It is shown that within certain limits, i.e., approximately 57% of yield stress, the properties of the material can be described by the constitutive equations of linear hereditary viscoelasticity. Above this limit, astress-dependent nonlinear viscoelastic theory must be used to characterize the properties of piezoelectric thin films.