Abstract
This paper discusses the studies on the internal flow field of droplets traveling in a rectangular microchannel by means of microparticle image velocimetry, specifically concentrating on the effects of capillary number, viscosity ratio and interfacial tension. The flow topology is predominantly dependent on the capillary number. It shows that the evident transitions from three pairs of recirculation zones at lower capillary numbers to one pair of recirculation zones near the sidewalls with low velocity in the central area at intermediate capillary numbers, then to a pair of recirculation zones closest to the axial centerline with high velocity in the central area at higher capillary numbers. There are two critical capillary numbers increasing with viscosity ratio in the evolution of flow features. Droplet size only influences two velocity components values other than the flow topology within intervals separated by the critical values. The equilibrium mechanism of viscous friction force and Marangoni stress dominate the internal topological transition in a surfactant added system. The obtained internal fluid phenomena inside droplets are beneficial to provide a guideline for screening of biochemical reaction conditions in the device.
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References
Afkhami S, Leshansky AM, Renardy Y (2011) Numerical investigation of elongated drops in a microfluidic T-junction. Phys Fluids 23:022002. https://doi.org/10.1063/1.3549266
Baret J-C, Kleinschmidt F, El Harrak A, Griffiths AD (2009) Kinetic aspects of emulsion stabilization by surfactants: a microfluidic analysis. Langmuir 25:6088–6093. https://doi.org/10.1021/la9000472
Baroud CN, Gallaire F, Dangla R (2010) Dynamics of microfluidic droplets. Lab Chip 10:2032–2045. https://doi.org/10.1039/C001191F
Bauer WA, Fischlechner M, Abell C, Huck WT (2010) Hydrophilic PDMS microchannels for high-throughput formation of oil-in-water microdroplets and water-in-oil-in-water double emulsions. Lab Chip 10:1814–1819. https://doi.org/10.1039/c004046k
Bithi SS, Vanapalli SA (2015) Collective dynamics of non-coalescing and coalescing droplets in microfluidic parking networks. Soft Matter 11:5122–5132. https://doi.org/10.1039/c5sm01077b
Boukellal H, Selimovic S, Jia Y, Cristobal G, Fraden S (2009) Simple, robust storage of drops and fluids in a microfluidic device. Lab Chip 9:331–338. https://doi.org/10.1039/b808579j
Bourdon CJ, Olsen MG, Gorby AD (2005) The depth of correlation in Micro-PIV for high numerical aperture and immersion objectives. J Fluids Eng 128:883–886. https://doi.org/10.1115/1.2201649
Dore V, Tsaoulidis D, Angeli P (2012) Mixing patterns in water plugs during water/ionic liquid segmented flow in microchannels. Chem Eng Sci 80:334–341. https://doi.org/10.1016/j.ces.2012.06.030
Fuerstman MJ, Lai A, Thurlow ME, Shevkoplyas SS, Stone HA, Whitesides GM (2007) The pressure drop along rectangular microchannels containing bubbles. Lab Chip 7:1479–1489. https://doi.org/10.1039/b706549c
Hein M, Moskopp M, Seemann R (2015) Flow field induced particle accumulation inside droplets in rectangular channels. Lab Chip 15:2879–2886. https://doi.org/10.1039/c5lc00420a
Hodges S, Jensen O, Rallison J (2004) The motion of a viscous drop through a cylindrical tube. J Fluid Mech 501:279–301. https://doi.org/10.1017/S0022112003007213
Jakiela S, Korczyk PM, Makulska S, Cybulski O, Garstecki P (2012) Discontinuous transition in a laminar fluid flow: a change of flow topology inside a droplet moving in a micron-size channel. Phys Rev Lett 108:134501. https://doi.org/10.1103/PhysRevLett.108.134501
Jeong HH, Jin SH, Lee BJ, Kim T, Lee CS (2015) Microfluidic static droplet array for analyzing microbial communication on a population gradient. Lab Chip 15:889–899. https://doi.org/10.1039/c4lc01097c
Kang DK et al (2014) Rapid detection of single bacteria in unprocessed blood using integrated comprehensive droplet digital detection. Nat Commun. https://doi.org/10.1038/ncomms6427
Kantak C, Zhu Q, Beyer S, Bansal T, Trau D (2012) Utilizing microfluidics to synthesize polyethylene glycol microbeads for Forster resonance energy transfer based glucose sensing. Biomicrofluidics 6:22006–220069. https://doi.org/10.1063/1.3694869
Kinoshita H, Kaneda S, Fujii T, Oshima M (2007) Three-dimensional measurement and visualization of internal flow of a moving droplet using confocal Micro-PIV. Lab Chip 7:338–346. https://doi.org/10.1039/b617391h
Kurup GK, Basu AS (2012) Field-free particle focusing in microfluidic plugs. Biomicrofluidics 6:022008. https://doi.org/10.1063/1.3700120
Labrot V, Schindler M, Guillot P, Colin A, Joanicot M (2009) Extracting the hydrodynamic resistance of droplets from their behavior in microchannel networks. Biomicrofluidics 3:12804. https://doi.org/10.1063/1.3109686
Leong CM, Gai Y, Tang SKY (2016) Internal flow in droplets within a concentrated emulsion flowing in a microchannel. Phys Fluids 28:112001. https://doi.org/10.1063/1.4968526
Li Y, Reddy RK, Kumar CS, Nandakumar K (2014) Computational investigations of the mixing performance inside liquid slugs generated by a microfluidic T-junction. Biomicrofluidics 8:054125. https://doi.org/10.1063/1.4900939
Ma S, Sherwood JM, Huck WTS, Balabani S (2014) On the flow topology inside droplets moving in rectangular microchannels. Lab Chip 14:3611–3620. https://doi.org/10.1039/C4LC00671B
Ma S, Sherwood JM, Huck WT, Balabani S (2015) The microenvironment of double emulsions in rectangular microchannels. Lab Chip 15:2327–2334. https://doi.org/10.1039/c5lc00346f
Mazutis L, Gilbert J, Ung WL, Weitz DA, Griffiths AD, Heyman JA (2013) Single-cell analysis and sorting using droplet-based microfluidics. Nat Protoc 8:870–891. https://doi.org/10.1038/nprot.2013.046
Miessner U, Lindken R, Westerweel J (2008) Velocity measurements in microscopic two-phase flows by means of micro PIV. In: ASME 2008 6th International Conference on Nanochannels, Microchannels, and Minichannels, pp 1111–1118. https://doi.org/10.1115/ICNMM2008-62093
Oishi M, Kinoshita H, Fujii T, Oshima M (2011) Simultaneous measurement of internal and surrounding flows of a moving droplet using multicolour confocal micro-particle image velocimetry (Micro-PIV). Meas Sci Technol 22:105401. https://doi.org/10.1088/0957-0233/22/10/105401
Parthiban P, Khan SA (2013) Bistability in droplet traffic at asymmetric microfluidic junctions. Biomicrofluidics 7:44123. https://doi.org/10.1063/1.4819276
Piao Y, Han DJ, Azad MR, Park M, Seo TS (2014) Enzyme incorporated microfluidic device for in situ glucose detection in water-in-air microdroplets. Biosens Bioelectron 65:220–225. https://doi.org/10.1016/j.bios.2014.10.032
Sajeesh P, Doble M, Sen AK (2014) Hydrodynamic resistance and mobility of deformable objects in microfluidic channels. Biomicrofluidics 8:054112. https://doi.org/10.1063/1.4897332
Sarrazin F, Bonometti T, Prat L, Gourdon C, Magnaudet J (2008) Hydrodynamic structures of droplets engineered in rectangular micro-channels. Microfluid Nanofluid 5:131–137. https://doi.org/10.1007/s10404-007-0233-9
Seemann R, Brinkmann M, Pfohl T, Herminghaus S (2012) Droplet based microfluidics. Rep Prog Phys 75:016601. https://doi.org/10.1088/0034-4885/75/1/016601
Teh SY, Lin R, Hung LH, Lee AP (2008) Droplet microfluidics. Lab Chip 8:198–220. https://doi.org/10.1039/b715524g
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The authors gratefully acknowledge the support of National Natural Science Foundation of China (Grant nos. 11572013, 11702007).
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Liu, Z., Zhang, L., Pang, Y. et al. Micro-PIV investigation of the internal flow transitions inside droplets traveling in a rectangular microchannel. Microfluid Nanofluid 21, 180 (2017). https://doi.org/10.1007/s10404-017-2019-z
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DOI: https://doi.org/10.1007/s10404-017-2019-z