Electro-Active Polymers in Non-Destructive Dielectric Evaluation

The piezoelectric nature and acoustic coupling constant K33 of corona-poled polyvinylidenefluoride (PVF2) have been investigated as a function of freqency extending in the MHz region, using different techniques. The frequency response of an electrostatic transducer using corona-poled polypropylene film (PP), as the sensing element, has also been studied and compared with that of corona-poled piezoelectric PVF2 film. The sensitivity and frequency response of piezoelectric PVF2 transducer appear to be comparable to those of electrostatic transducer using polypropylene and employing a large bias field.