PZT/P(VDF-TrFE) nanocomposites for ultrasonic hydrophone application

0-3 composites with nanosized lead zirconate titanate (PZT) powder imbedded in a vinylidene fluoride-trifluoroethylene copolymer (P(VDF-TrFE)) matrix have been fabricated. Since the piezoelectric coefficients of PZT and P(VDF-TrFE) have opposite signs, the PZT and P(VDF-TrFE) phases in the nanocomposites were poled in opposite directions in order to enhance the piezoelectric activity. The PZT powder, prepared by a sol-gel process, has a tetragonal structure. The ratio of the (002) and (200) X-ray diffraction peaks was used as a measure of the degree of poling in the ceramic phase. The piezoelectric coefficient of the nanocomposite film was measured by a laser interferometry technique. A needle type hydrophone for the calibration of medical ultrasonic transducers was fabricated using the nanocomposite as the sensing element and its performance was evaluated