Asynchronous generation of oil droplets using a microfluidic flow focusing system

Thurgood, Peter; Baratchi, Sara; Arash, Aram; Pirogova, Elena; Jex, Aaron R.; Khoshmanesh, Khashayar

doi:10.1038/s41598-019-47078-8

Cited by 15 publications

(13 citation statements)

References 46 publications

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“…The increase in surface energy was evident at the polar component = + 234 % but also at the dispersive component = + 22 %, Figure 3. Measured and calculated values of the contact angle between both liquids and the surface of the polymer film and the values of surface energy are also confirmed by the literature [27][28][29][30].…”

Section: Wettability Of Surfaces -Determination Of the Contact Angle ...supporting

confidence: 80%

Application of diffuse coplanar surface barrier plasma discharge to polymeric materials

Janík¹,

Kohutiar

Pajtášová³

et al. 2022

Materialwissenschaft Werkst

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The KPR 200 mm plasma reactor is a device designed for the surface modification of various materials. Such a modification occurs by applying a unique type of plasma – plasma generated on a ceramic dielectric. The ceramic dielectric is a durable system with which it is possible to continuously modify the surfaces of materials with such a plasma. The advantage of applying this unique type of plasma is that the modification of the materials occurs at room temperature and atmosphere. However, it is necessary to monitor and observe certain parameters, for example: the selected power, the exposure time of the surfaces of the modified materials, and the distance of the surface from the ceramic dielectric itself. Therefore, in the present paper, the effect of diffuse coplanar surface barrier discharge (DCSBD) plasma discharge on selected polymeric materials was investigated. Plasma impact assessment was also performed using image analysis, that could provide relevant information in the process of plasma‐chemical modification. Changes in the surfaces of the investigated thin polyvynil chloride material, before and after exposure to plasma discharge, were also observed (changes in contact angle, atomic force microscopy).

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Section: Wettability Of Surfaces -Determination Of the Contact Angle ...supporting

confidence: 80%

Application of diffuse coplanar surface barrier plasma discharge to polymeric materials

Janík¹,

Kohutiar

Pajtášová³

et al. 2022

Materialwissenschaft Werkst

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show abstract

“…Consequently, as the total flow rate increases, the bubbles form with a higher frequency through the squeezing process forced by the shear stress and resistance. In other words, the pressure-driven flow by controlling Q Pump determines the flow rate of each fluid through the flow channel, and allows liquid slugs to dynamically be changed such as length or frequency 65 . Further, the air bubble, which can be considered as a gap between neighboring slugs, also varies with different vacuum pressure.…”

Section: Discussionmentioning

confidence: 99%

“…One of the areas is the effect of surface property in the channel. It can affect the generation process of gas–liquid segmented flow 68 , and the configuration of liquid slugs can be altered by the channel surface such as wetting properties via coating 65 . 3D printing channel is also considered as research field in terms of influence of surface affinity on droplet generator 69 .…”

Section: Discussionmentioning

confidence: 99%

Quantitative study for control of air–liquid segmented flow in a 3D-printed chip using a vacuum-driven system

Hong

Song

Yeom

2022

Sci Rep

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The formation of droplets or bubbles in a microfluidic system is a significant topic requiring device miniaturization and a small volume of samples. Especially, a two-phase segmented flow can be applied to micro-mixing for chemical reactions and the treatment of heat and mass transfer. In this study, a flow of liquid slugs and bubbles was generated in a 3D-printed chip and controlled by a single pump creating a vacuum at the outlet. The pump and chip device were integrated to form a simple and portable system. The size and flow rate of liquid slugs, obtained through image processing techniques, were analyzed considering several parameters related to hydraulic resistance and pressure drop. In addition, the effect of segmentation on mixing was observed by measuring the intensity change using two different colored inks. The hydraulic resistance of air and liquid flows can be controlled by changing the tube length of air flow and the viscosity of liquid flow. Because the total pressure drop along the channel was produced using a single pump at the outlet of the channel, the size and flow rate of the liquid slugs showed a near linear relation depending on the hydraulic resistances. In contrast, as the total pressure varied with the flow rate of the pump, the size of the liquid slugs showed a nonlinear trend. This indicates that the frequency of the liquid slug formation induced by the squeezed bubble may be affected by several forces during the development of the liquid slugs and bubbles. In addition, each volume of liquid slug segmented by the air is within the range of 10–1 to 2 µL for this microfluidic system. The segmentation contributes to mixing efficiency based on the increased homogeneity factor of liquid. This study provides a new insight to better understand the liquid slug or droplet formation and predict the segmented flow based on the relationship between the resistance, flow rate, and pressure drop.

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“…Such platforms offer improved turnaround times because of the elimination of physical photomasks, user-friendly interfaces, and reduced prototyping times [36]. For example, Heidelberg maskless aligners have been used to produce biosensors and microfluidic devices [39][40][41][42]. DMD-based systems in general, therefore, offer tremendous potential to improve the prototyping stages of device microfabrication.…”

Section: Introductionmentioning

confidence: 99%

Rapid Prototyping of Organ-on-a-Chip Devices Using Maskless Photolithography

et al. 2021

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Organ-on-a-chip (OoC) and microfluidic devices are conventionally produced using microfabrication procedures that require cleanrooms, silicon wafers, and photomasks. The prototyping stage often requires multiple iterations of design steps. A simplified prototyping process could therefore offer major advantages. Here, we describe a rapid and cleanroom-free microfabrication method using maskless photolithography. The approach utilizes a commercial digital micromirror device (DMD)-based setup using 375 nm UV light for backside exposure of an epoxy-based negative photoresist (SU-8) on glass coverslips. We show that microstructures of various geometries and dimensions, microgrooves, and microchannels of different heights can be fabricated. New SU-8 molds and soft lithography-based polydimethylsiloxane (PDMS) chips can thus be produced within hours. We further show that backside UV exposure and grayscale photolithography allow structures of different heights or structures with height gradients to be developed using a single-step fabrication process. Using this approach: (1) digital photomasks can be designed, projected, and quickly adjusted if needed; and (2) SU-8 molds can be fabricated without cleanroom availability, which in turn (3) reduces microfabrication time and costs and (4) expedites prototyping of new OoC devices.

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Asynchronous generation of oil droplets using a microfluidic flow focusing system

Cited by 15 publications

References 46 publications

Application of diffuse coplanar surface barrier plasma discharge to polymeric materials

Application of diffuse coplanar surface barrier plasma discharge to polymeric materials

Quantitative study for control of air–liquid segmented flow in a 3D-printed chip using a vacuum-driven system

Rapid Prototyping of Organ-on-a-Chip Devices Using Maskless Photolithography

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