Nanocomposite ultrasonic hydrophones

Needle-type hydrophones for the calibration of medical ultrasonic transduce rs have been fabricated using lead zirconate titanate (PZT)/poly(vinylidene fluoride-trifluoroethylene) (PZT/P(VDF-TrFE)) 0-3 nanocomposite films. The 0-3 nanocomposite film has been prepared by incorporating nanosized PZT po wder (derived from a sol-gel process) in a P(VDF-TrFE) matrix. Since the pi ezoelectric coefficients of PZT and P(VDF-TrFE) have opposite signs,the PZT and P(VDF-TrFE) phases In the nanocomposites have been poled in opposite d irections in order to give enhanced piezoelectric activity. A nanocomposite hydrophone with 0.2 volume fraction of PZT has been characterized and foun d to be more sensitive than a P(VDF-TrFE) hydrophone of similar structure. (C) 1999 Elsevier Science S.A. All rights reserved.