Effects of surfactants on the formation of microdroplets in the flow focusing microfluidic device

Wu, Nan; Zhu, Yonggang; Leech, Patrick W.; Sexton, B.A.; Brown, Sue; Easton, Christopher D.

doi:10.1117/12.769326

Cited by 8 publications

(3 citation statements)

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“…Use of surfactants in T-junction microchannels results in a decrease in droplet diameter compared with those systems without surfactants (van der Graaf et al, 2005). Furthermore, droplet size decreases with an increasing concentration of surfactant in the continuous phase, and even smaller droplets are formed in the presence of surfactants in the dispersed phase in flow-focusing microchannels (Wu et al, 2008). The influence of surfactant concentration in straight-through MC emulsification varies with the viscosity of the dispersed phase Z d .…”

Section: Effect Of Phase Parametersmentioning

confidence: 98%

Two-phase microfluidic flows

Zhao

Middelberg

2011

Chemical Engineering Science

342

201

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Section: Effect Of Phase Parametersmentioning

confidence: 98%

Two-phase microfluidic flows

Zhao

Middelberg

2011

Chemical Engineering Science

342

201

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“…Currently, microdroplet generation frequently adopts the technology of droplet-based microfluidics or digital microfluidics, which is a subclass of microfluidic devices, wherein droplets are generated using T-junctions [ 7 , 8 , 9 ] or flow-focusing devices [ 10 , 11 ]. In a microfluidic flow-focusing device, the microdroplets or plugs streak under an oil layer.…”

Section: Introductionmentioning

confidence: 99%

Size-Adjustable Microdroplets Generation Based on Microinjection

Zheng

et al. 2017

Micromachines

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Microinjection is a promising tool for microdroplet generation, while the microinjection for microdroplets generation still remains a challenging issue due to the Laplace pressure at the micropipette opening. Here, we apply a simple and robust substrate-contacting microinjection method to microdroplet generation, presenting a size-adjustable microdroplets generation method based on a critical injection (CI) model. Firstly, the micropipette is adjusted to a preset injection pressure. Secondly, the micropipette is moved down to contact the substrate, then, the Laplace pressure in the droplet is no longer relevant and the liquid flows out in time. The liquid constantly flows out until the micropipette is lifted, ending the substrate-contacting situation, which results in the recovery of the Laplace pressure at the micropipette opening, and the liquid injection is terminated. We carry out five groups of experiments whereupon 1600 images are captured within each group and the microdroplet radius of each image is detected. Then we determine the relationship among microdroplet radius, radius at the micropipette opening, time, and pressure, and, two more experiments are conducted to verify the relationship. To verify the effectiveness of the substrate-contacting method and the relationship, we conducted two experiments with six desired microdroplet radii are set in each experiment, by adjusting the injection time with a given pressure, and adjusting the injection pressure with a given time. Then, six arrays of microdroplets are obtained in each experiment. The results of the experiments show that the standard errors of the microdroplet radii are less than 2% and the experimental errors fall in the range of ±5%. The average operating speed is 20 microdroplets/min and the minimum radius of the microdroplets is 25 μm. This method has a simple experimental setup that enables easy manipulation and lower cost.

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“…The generation and manipulation of droplets are achieved by either passive or active means. Passive methods generate and manipulate droplets with different channel configurations such as a T-junction [8][9][10][11][12][13][14] and flow focusing [15][16][17][18][19][20][21]. However, these fixed channel configurations only allow the 3 To whom correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

Formation and manipulation of ferrofluid droplets at a microfluidicT-junction

Tan

Nguyen

Yobaş

et al. 2010

J. Micromech. Microeng.

128

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This paper reports the formation and manipulation of ferrofluid droplets at a microfluidic T-junction in the presence of a permanent magnetic field. A small circular permanent magnet with a diameter of 3 mm is used to controls the size of the ferrofluid droplets within a microfluidic device. In the absence of a magnetic field, the size of the ferrofluid droplets decreases linearly with the increase of the flow rate of the continuous phase. In the presence of a magnetic field, the size of the droplets depends on the magnetic field strength, magnetic field gradient and the magnetization of the ferrofluid. The magnetic field strength is adjusted in our experiment by the location of the magnet. The induced attractive magnetic force affects the droplet formation process leading to the change in size of the formed droplets. Experimental observation also shows that the relative change in the size of the droplet depends on the flow rate of the continuous phase. Furthermore, the paper compares the evolving shape of the ferrofluid droplet during the formation process with and without the magnetic field.

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Effects of surfactants on the formation of microdroplets in the flow focusing microfluidic device

Cited by 8 publications

References 0 publications

Two-phase microfluidic flows

Two-phase microfluidic flows

Size-Adjustable Microdroplets Generation Based on Microinjection

Formation and manipulation of ferrofluid droplets at a microfluidicT-junction

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