PVDF copolymer transducers used to evaluate microparticle suspensions

The ability of using high frequency ultrasonic transducers made from piezoelectric polymers, to characterize microparticle suspensions, has been investigated both in an experimental setup and in a numerical model. Both investigations, which consider microparticles settled on a glass substrate, show that the backscattered frequency spectra contain a number of minima values arising from wave resonances in the microparticles. The locations of these resonances are in the experiments, found to be independent of the particle concentration, but strongly dependent on the particle size. A comparison to previous results for floating microspheres, show that the material properties of the glass substrate, also has to be included for obtaining the correct resonance frequencies for settled particles.