Measurements of the response of gas-filled micropores to ultrasound by using PVDF transducers

Abstract

Techniques that use hydrophobic polycarbonate thin sheets containing randomly spaced, fairly uniform small holes, immersed in water to trap air bubbles, have been found useful in biophysical experiments. Using such sheets, the scattering from a stable array of small air-filled holes exposed to ultrasound has been investigated [D. L. Miller, J. Acoust. Soc. Am. 71, 471–476 (1982)]. A set of piezoelectric crystal transducers of high-quality factor were used during the earlier study, which allowed measurements to be made at a discrete set of frequencies. In the present work, utilization of PVDF transducers, which have flat frequency response in the range of interest, makes it possible to study the continuous frequency response of the trapped bubbles. Results of the new experiments will be presented and discussed. [Work supported by institutional funds of University of Vermont.]