Microparticle Acoustophoresis in Aluminum-Based Acoustofluidic Devices with PDMS Covers

William Naundrup Bodé*, Lei Jiang, Thomas Laurell, Henrik Bruus

*Corresponding author for this work

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Abstract

We present a numerical model for the recently introduced simple and inexpensive micromachined aluminum devices with a polydimethylsiloxane (PDMS) cover for microparticle acoustophoresis. We validate the model experimentally for a basic design, where a microchannel is milled into the surface of an aluminum substrate, sealed with a PDMS cover, and driven at MHz frequencies by a piezoelectric lead-zirconate-titanate (PZT) transducer. Both experimentally and numerically we find that the soft PDMS cover suppresses the Rayleigh streaming rolls in the bulk. However, due to the low transverse speed of sound in PDMS, such devices are prone to exhibit acoustic streaming vortices in the corners with a relatively large velocity. We predict numerically that in devices, where the microchannel is milled all the way through the aluminum substrate and sealed with a PDMS cover on both the top and bottom, the Rayleigh streaming is suppressed in the bulk thus enabling focusing of sub-micrometer-sized particles.
Original languageEnglish
Article number292
JournalMicromachines
Volume11
Issue number3
Number of pages15
ISSN2072-666X
DOIs
Publication statusPublished - 2020

Keywords

  • Acoustofluidics
  • Microparticle acoustophoresis
  • Numerical modeling
  • Aluminum microdevices
  • Polydimethylsiloxane (PDMS) covers

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