PROPERTIES OF TRANSVERSE ULTRASONIC TRANSDUCERS OF FERROELECTRIC POLYMERS WORKING IN THICKNESS-SHEAR MODES

Shear piezoelectric properties of poly(vinylidene fluoride) (PVDF) and copolymer of vinylidene fluoride and trifluoroethylene [P(VDF/TrFE)] have been studied precisely in a wide temperature range from 10 to 400 K. It was found that these polymers have the shear electromechanical coupling factors k(15) and k(24) large enough to be utilized for trans verse ultrasonic transducers operating in a wide frequency range and i n a wide temperature range below 400 K. Shear mode ultrasonic transduc ers of P(VDF/TrFE) were fabricated and their performances were studied both experimentally and theoretically. The shear polymer transducers are useful for generation and detection of transverse ultrasonic waves .