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dc.contributor.author
Lamprecht, Andreas
dc.contributor.author
Goering, Christoph
dc.contributor.author
Schaap, Iwan A.T.
dc.contributor.author
Dual, Jürg
dc.date.accessioned
2021-03-04T08:51:49Z
dc.date.available
2021-03-04T04:21:43Z
dc.date.available
2021-03-04T08:51:49Z
dc.date.issued
2021-03
dc.identifier.issn
0960-1317
dc.identifier.issn
1361-6439
dc.identifier.other
10.1088/1361-6439/abde92
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/472823
dc.description.abstract
Two orthogonal standing acoustic waves, generated by piezoelectric excitation, can form a two-dimensional pressure field in microfluidic devices. A phase difference of the excitation waves can be employed to rotate spherical µm-sized silica particles by a torque mediated through the viscous boundary δ around the particle. The measurement of the rotational rate is, so far, limited to high-speed cameras and their frame rate, and gets increasingly difficult when the sphere gets smaller. We report here a new method for measuring the rotational rate of µm sized spherical particles. We utilize an optical trap with high-speed position detection to overcome the frame rate limitation of wide field image recording. The power spectrum of an optically trapped, rotating particle reveals additional peaks corresponding to the rotational frequencies—compared to a non-rotating particle. We validate our method at low rotational rates against high-speed video observation. To demonstrate the potential of this method we addressed a recent controversy about the rotation of particles with a relatively large viscous boundary layer δ. We measured steady-state rotational rates up to 229 Hz (13.8 × 103 rpm) for a particle with a radius R ≈ δ. Recent numerical research suggests that in this regime the existing theoretical approach (valid for $R\gg\delta$) overpredicts the steady-state rotational rate by a factor of 10. With our new method we also confirm the numerical results experimentally. © 2021 IOP Publishing
en_US
dc.language.iso
en
en_US
dc.publisher
Institute of Physics
en_US
dc.subject
optical tweezers
en_US
dc.subject
acoustofluidic
en_US
dc.subject
acoustic viscous torque
en_US
dc.subject
microfluidics
en_US
dc.subject
rotation measurement
en_US
dc.title
Rotational speed measurements of small spherical particles driven by acoustic viscous torques utilizing an optical trap
en_US
dc.type
Journal Article
dc.date.published
2021-02-10
ethz.journal.title
Journal of Micromechanics and Microengineering
ethz.journal.volume
31
en_US
ethz.journal.issue
3
en_US
ethz.journal.abbreviated
J. micromechanics microengineering
ethz.pages.start
034004
en_US
ethz.size
11 p.
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Bristol
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02130 - Dep. Maschinenbau und Verfahrenstechnik / Dep. of Mechanical and Process Eng.::02618 - Institut für Mechanische Systeme / Institute of Mechanical Systems::03307 - Dual, Jürg (emeritus) / Dual, Jürg (emeritus)
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02130 - Dep. Maschinenbau und Verfahrenstechnik / Dep. of Mechanical and Process Eng.::02618 - Institut für Mechanische Systeme / Institute of Mechanical Systems::03307 - Dual, Jürg (emeritus) / Dual, Jürg (emeritus)
ethz.date.deposited
2021-03-04T04:21:51Z
ethz.source
SCOPUS
ethz.eth
yes
en_US
ethz.availability
Metadata only
en_US
ethz.rosetta.installDate
2021-03-04T08:51:59Z
ethz.rosetta.lastUpdated
2022-03-29T05:36:41Z
ethz.rosetta.exportRequired
true
ethz.rosetta.versionExported
true
ethz.COinS
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