Piezoelectric polymers in non-destructive dielectric evaluation

Thin films of polyvinylidene fluoride (PVF2) can be rendered piezoelectric by corona poling at suitably high electric fields. The mechanical strength of the film, together with its flexibility and reasonably flat piezo-electric response over a wide bandwidth, makes it useful for the detection of acoustic emission signals which may originate from deformation and flow propagation in a material under dynamic or static loading. Present work reports an evaluation of the piezoelectric response and the electro-mechanical coupling coefficient k332 in corona-poled PVF2 over a frequency range of 10 Hz to 1 MHz.