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Acoustofluidic Measurements on Polymer-Coated Microbubbles: Primary and Secondary Bjerknes Forces
- Source :
- Micromachines, Volume 9, Issue 8, Micromachines, Vol 9, Iss 8, p 404 (2018)
- Publication Year :
- 2018
-
Abstract
- The acoustically-driven dynamics of isolated particle-like objects in microfluidic environments is a well-characterised phenomenon, which has been the subject of many studies. Conversely, very few acoustofluidic researchers looked at coated microbubbles, despite their widespread use in diagnostic imaging and the need for a precise characterisation of their acoustically-driven behaviour, underpinning therapeutic applications. The main reason is that microbubbles behave differently, due to their larger compressibility, exhibiting much stronger interactions with the unperturbed acoustic field (primary Bjerknes forces) or with other bubbles (secondary Bjerknes forces). In this paper, we study the translational dynamics of commercially-available polymer-coated microbubbles in a standing-wave acoustofluidic device. At increasing acoustic driving pressures, we measure acoustic forces on isolated bubbles, quantify bubble-bubble interaction forces during doublet formation and study the occurrence of sub-wavelength structures during aggregation. We present a dynamic characterisation of microbubble compressibility with acoustic pressure, highlighting a threshold pressure below which bubbles can be treated as uncoated. Thanks to benchmarking measurements under a scanning electron microscope, we interpret this threshold as the onset of buckling, providing a quantitative measurement of this parameter at the single-bubble level. For acoustofluidic applications, our results highlight the limitations of treating microbubbles as a special case of solid particles. Our findings will impact applications where knowing the buckling pressure of coated microbubbles has a key role, like diagnostics and drug delivery.
- Subjects :
- 47.35.Rs
43.25.Qp
Interaction forces
Materials science
lcsh:Mechanical engineering and machinery
Microfluidics
43.25.Yw
QC0221
02 engineering and technology
01 natural sciences
Article
microbubbles
62.20.mq
0103 physical sciences
lcsh:TJ1-1570
Electrical and Electronic Engineering
Sound pressure
010301 acoustics
TA0365
chemistry.chemical_classification
Acoustic field
Solid particle
Mechanical Engineering
Polymer
Mechanics
021001 nanoscience & nanotechnology
Bjerknes forces
chemistry
acoustofluidics
Control and Systems Engineering
Compressibility
Microbubbles
compressibility
43.25.+y
0210 nano-technology
Subjects
Details
- ISSN :
- 2072666X
- Volume :
- 9
- Issue :
- 8
- Database :
- OpenAIRE
- Journal :
- Micromachines
- Accession number :
- edsair.doi.dedup.....e1b8aa650ea30e229b5fc340e45a6117