Abstract
We investigated the influence of an alternate current (AC) electric field on droplet generation in a T-junction device. We used sodium chloride solution with various conductivities to adjust the response time of the fluidic system. At constant flow rates of both continuous and dispersed phases, the critical parameters for the droplet formation process are the magnitude, the frequency of the applied voltage and the conductivity of the dispersed phase. The response of the droplet formation process to AC excitation is characterised by the relative area of the formed droplet. The relative response time of the fluidic system to the applied AC voltage is characterised by the relative response time that is proportional to the ratio of the AC frequency to the conductivity of the dispersed phase. An accurate prediction of the breakdown voltage for the walls also proved robustness of our model. Furthermore, experiments were repeated with 0.5 g/L and 1 g/L xanthan gum solutions as non-Newtonian fluids. The results reveal the negligible influence of viscoelasticity on the droplet formation process. On-demand size controllable generation of non-Newtonian droplets is subsequently demonstrated following the same trend of the Newtonian counterparts.
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References
Abate AR et al (2013) DNA sequence analysis with droplet-based microfluidics. Lab Chip 13:4864–4869. https://doi.org/10.1039/c3lc50905b
Aleksandrov AA, Dzhuraeva E, Utenkov V (2012) Viscosity of aqueous solutions of sodium chloride. High Temp 50:354–358
Baret J-C et al (2009) Fluorescence-activated droplet sorting (FADS): efficient microfluidic cell sorting based on enzymatic activity. Lab Chip 9:1850–1858. https://doi.org/10.1039/b902504a
Castro-Hernández E, García-Sánchez P, Tan SH, Gañán-Calvo AM, Baret J-C, Ramos A (2015) Breakup length of AC electrified jets in a microfluidic flow-focusing junction. Microfluid Nanofluid 19:787–794. https://doi.org/10.1007/s10404-015-1603-3
Chaudhuri J, Timung S, Dandamudi CB, Mandal TK, Bandyopadhyay D (2017) Discrete electric field mediated droplet splitting in microchannels: Fission, Cascade, and Rayleigh modes. Electrophoresis 38:278–286
Chong ZZ, Tor SB, Gañán-Calvo AM, Chong ZJ, Loh NH, Nguyen N-T, Tan SH (2016) Automated droplet measurement (ADM): an enhanced video processing software for rapid droplet measurements. Microfluidics Nanofluidics 20:1–14
Christopher GF, Anna SL (2007) Microfluidic methods for generating continuous droplet streams. J Phys D Appl Phys 40:R319
Gañán-Calvo AM, Guo W, Xi H-D, Teo AJ, Nguyen N-T, Tan SH (2018) Pressure-driven filling of liquid metal in closed-end microchannels. Phys Rev E 98:032602
Garstecki P, Fuerstman MJ, Stone HA, Whitesides GM (2006) Formation of droplets and bubbles in a microfluidic T-junction—scaling and mechanism of break-up. Lab Chip 6:437–446. https://doi.org/10.1039/b510841a
Gu H, Malloggi F, Vanapalli SA, Mugele F (2008) Electrowetting-enhanced microfluidic device for drop generation. Appl Phys Lett 93:183507. https://doi.org/10.1063/1.3013567
Guo W, Teo AJT, Gañán-Calvo AM, Song C, Nguyen N-T, Xi H-D, Tan SH (2018) Pressure-driven filling of closed-end microchannel: realization of comb-shaped transducers for acoustofluidics. Phys Rev Appl 10:054045. https://doi.org/10.1103/PhysRevApplied.10.054045
Huang Y, Wang YL, Wong TN (2017) AC electric field controlled non-Newtonian filament thinning and droplet formation on the microscale. Lab Chip 17:2969–2981. https://doi.org/10.1039/C7LC00420F
Katzbauer B (1998) Properties and applications of xanthan gum. Polym Degrad Stab 59:81–84. https://doi.org/10.1016/S0141-3910(97)00180-8
Li X-B, Li F-C, Yang J-C, Kinoshita H, Oishi M, Oshima M (2012) Study on the mechanism of droplet formation in T-junction microchannel. Chem Eng Sci 69:340–351. https://doi.org/10.1016/j.ces.2011.10.048
Link DR et al (2006) Electric control of droplets in microfluidic devices. Angew Chem Int Ed 45:2556–2560
Ma Z, Teo AJT, Tan SH, Ai Y, Nguyen N-T (2016) Self-aligned interdigitated transducers for acoustofluidics. Micromachines 7:216
Malloggi F, Vanapalli SA, Gu H, van den Ende D, Mugele F (2007) Electrowetting-controlled droplet generation in a microfluidic flow-focusing device. J Phys Condensed Matter 19:462101
Rochefort WE, Middleman S (1987) Rheology of xanthan gum: salt, temperature, and strain effects in oscillatory and steady shear experiments. J Rheol 31:337–369
Saville D (1997) Electrohydrodynamics: the Taylor-Melcher leaky dielectric model. Annu Rev Fluid Mech 29:27–64
Schneider T, Kreutz J, Chiu DT (2013) The potential impact of droplet microfluidics in biology. Anal Chem 85:3476–3482
Shojaeian M, Hardt S (2018) Fast electric control of the droplet size in a microfluidic T-junction droplet generator. Appl Phys Lett 112:194102
Tam K, Tiu C (1989) Steady and dynamic shear properties of aqueous polymer solutions. J Rheol 33:257–280
Tan SH, Nguyen N-T (2011) Generation and manipulation of monodispersed ferrofluid emulsions: The effect of a uniform magnetic field in flow-focusing and T-junction configurations. Phys Rev E 84:036317
Tan SH, Maes F, Semin B, Vrignon J, Baret J-C (2014a) The Microfluidic Jukebox. Sci Rep 4:4787. https://doi.org/10.1038/srep04787
Tan SH, Semin B, Baret J-C (2014b) Microfluidic flow-focusing in ac electric fields. Lab Chip 14:1099–1106
Teo AJT et al (2017) Negative pressure induced droplet generation in a microfluidic flow-focusing device. Anal Chem. https://doi.org/10.1021/acs.analchem.6b05053
Thiam AR, Bremond N, Bibette J (2009) Breaking of an emulsion under an ac electric field. Phys Rev Lett 102:188304
Whitesides GM (2006) The origins and the future of microfluidics. Nature 442:368
Xi H-D, Guo W, Leniart M, Chong ZZ, Tan SH (2016) AC electric field induced droplet deformation in a microfluidic T-junction. Lab Chip 16:2982–2986. https://doi.org/10.1039/C6LC00448B
Xu J, Li S, Tan J, Luo G (2008) Correlations of droplet formation in T-junction microfluidic devices: from squeezing to dripping. Microfluid Nanofluid 5:711–717
Yeo LY, Lastochkin D, Wang S-C, Chang H-C (2004) A new ac electrospray mechanism by maxwell-wagner polarization and capillary resonance. Phys Rev Lett 92:133902. https://doi.org/10.1103/PhysRevLett.92.133902
Yoon DH et al (2014) Active microdroplet merging by hydrodynamic flow control using a pneumatic actuator-assisted pillar structure. Lab Chip 14:3050–3055. https://doi.org/10.1039/C4LC00378K
Acknowledgements
The authors acknowledge the Australian Research Council for funding support through the grant DE170100600. This work was performed in part at the Queensland node of the Australian National Fabrication Facility, a company established under the National Collaborative Research Infrastructure Strategy to provide nano- and micro-fabrication facilities for Australia’s researchers.
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Teo, A.J.T., Yan, M., Dong, J. et al. Controllable droplet generation at a microfluidic T-junction using AC electric field. Microfluid Nanofluid 24, 21 (2020). https://doi.org/10.1007/s10404-020-2327-6
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DOI: https://doi.org/10.1007/s10404-020-2327-6