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A droplet-based microfluidic system capable of droplet formation and manipulation

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Abstract

Formation of emulsion droplets is crucial for a variety of industrial and scientific applications. This study presents a new droplet-based microfluidic system capable of generating tunable and uniform-sized droplets and subsequently deflecting these droplets at various inclination angles using a combination of flow-focusing and moving-wall structures. A pneumatic air chamber was used to activate the moving-wall structures, located nearby the outlet of the flow-focusing microchannels, such that the sheath flows can be locally accelerated. With this approach, the size of the droplets can be fine-tuned and sorted without adjusting the syringe pumps. Experimental data showed that droplets with diameters ranging from 31.4 to 146.2 μm with a variation of less than 5.39% can be generated. Besides, droplets can be sorted upwards or backwards with an inclination angle ranging from 0° to 53.5°. The development of this emulsion system may be promising for the formation and collection of emulsion products for applications in the pharmaceutical, cosmetics and food industries.

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Abbreviations

CCD:

Charge-coupled device

CV:

Coefficient of variation

EMV:

Electromagnetic valve

MEMS:

Micro-electro-mechanical-systems

PDMS:

Polydimethylsiloxane

P 1 :

Air pressure injected to the upper moving-wall

P 2 :

Air pressure injected to the lower moving-wall

SEM:

Scanning electron microscope

V 1 :

Sample flow velocity

V 2 :

Sheath flow velocity

o/w:

Oil-in-water

w/o:

Water-in-oil

o/w/o:

Oil-in-water-in-oil

w/o/w:

Water-in-oil-in-water

δ1 :

Deformation of the upper moving-wall

δ2 :

Deformation of the lower moving-wall

θ:

Inclination angle of emulsion droplets

φ:

Outlet angle of the orifice

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Acknowledgments

The authors would like to thank the National Science Council in Taiwan for their financial support (NSC 96-2120-M-006-008).

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Authors and Affiliations

  1. Institution of Nanotechnology and Microsystems Engineering, National Cheng Kung University, Tainan, 701, Taiwan

    Chen-Yi Lee & Gwo-Bin Lee

  2. Department of Engineering Science, National Cheng Kung University, Tainan, 701, Taiwan

    Yen-Heng Lin & Gwo-Bin Lee

  3. Medical Electronics and Device Technology Center, Industrial Technology Research Institute, Hsinchu, 310, Taiwan

    Gwo-Bin Lee

Authors
  1. Chen-Yi Lee
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  2. Yen-Heng Lin
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Correspondence to Gwo-Bin Lee.

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Lee, CY., Lin, YH. & Lee, GB. A droplet-based microfluidic system capable of droplet formation and manipulation. Microfluid Nanofluid 6, 599–610 (2009). https://doi.org/10.1007/s10404-008-0340-2

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  • DOI: https://doi.org/10.1007/s10404-008-0340-2

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