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A microfluidic device based on an evaporation-driven micropump.

Nie C, Frijns AJ, Mandamparambil R, den Toonder JM - Biomed Microdevices (2015)

Bottom Line: Typical results show that with 1 to 61 pores (diameter = 250 μm, pitch = 500 μm) flow rates of 7.3 × 10(-3) to 1.2 × 10(-1) μL/min are achieved.The results are theoretically analyzed using an evaporation model that includes an evaporation correction factor.The theoretical and experimental results are in good agreement.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.

ABSTRACT
In this paper we introduce a microfluidic device ultimately to be applied as a wearable sweat sensor. We show proof-of-principle of the microfluidic functions of the device, namely fluid collection and continuous fluid flow pumping. A filter-paper based layer, that eventually will form the interface between the device and the skin, is used to collect the fluid (e.g., sweat) and enter this into the microfluidic device. A controllable evaporation driven pump is used to drive a continuous fluid flow through a microfluidic channel and over a sensing area. The key element of the pump is a micro-porous membrane mounted at the channel outlet, such that a pore array with a regular hexagonal arrangement is realized through which the fluid evaporates, which drives the flow within the channel. The system is completely fabricated on flexible polyethylene terephthalate (PET) foils, which can be the backbone material for flexible electronics applications, such that it is compatible with volume production approaches like Roll-to-Roll technology. The evaporation rate can be controlled by varying the outlet geometry and the temperature. The generated flows are analyzed experimentally using Particle Tracking Velocimetry (PTV). Typical results show that with 1 to 61 pores (diameter = 250 μm, pitch = 500 μm) flow rates of 7.3 × 10(-3) to 1.2 × 10(-1) μL/min are achieved. When the surface temperature is increased by 9.4°C, the flow rate is increased by 130 %. The results are theoretically analyzed using an evaporation model that includes an evaporation correction factor. The theoretical and experimental results are in good agreement.

No MeSH data available.


The evaporation correction factor vs. number of pores for different diameters D (μm) in a hexagonal array with a pitch of 500 μm
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Fig6: The evaporation correction factor vs. number of pores for different diameters D (μm) in a hexagonal array with a pitch of 500 μm

Mentions: In the devices, the pores are distributed hexagonally. The evaporation correction factor is calculated through Equations 4 to 6. The pitch of the matrix of pores is set to 500 μm. Figure 6 shows the reduction of the mean evaporation correction factor when the number of pores increases. The evaporation correction factor also reduces for increasing pore size (while keeping the pitch constant) due to enhanced interaction between the pores. Although the evaporation flux per pore decreases with the number of pores, still the total evaporation rate increases slowly by adding more pores into the matrix because of the factor N in Equation 7.Fig. 6


A microfluidic device based on an evaporation-driven micropump.

Nie C, Frijns AJ, Mandamparambil R, den Toonder JM - Biomed Microdevices (2015)

The evaporation correction factor vs. number of pores for different diameters D (μm) in a hexagonal array with a pitch of 500 μm
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4372687&req=5

Fig6: The evaporation correction factor vs. number of pores for different diameters D (μm) in a hexagonal array with a pitch of 500 μm
Mentions: In the devices, the pores are distributed hexagonally. The evaporation correction factor is calculated through Equations 4 to 6. The pitch of the matrix of pores is set to 500 μm. Figure 6 shows the reduction of the mean evaporation correction factor when the number of pores increases. The evaporation correction factor also reduces for increasing pore size (while keeping the pitch constant) due to enhanced interaction between the pores. Although the evaporation flux per pore decreases with the number of pores, still the total evaporation rate increases slowly by adding more pores into the matrix because of the factor N in Equation 7.Fig. 6

Bottom Line: Typical results show that with 1 to 61 pores (diameter = 250 μm, pitch = 500 μm) flow rates of 7.3 × 10(-3) to 1.2 × 10(-1) μL/min are achieved.The results are theoretically analyzed using an evaporation model that includes an evaporation correction factor.The theoretical and experimental results are in good agreement.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.

ABSTRACT
In this paper we introduce a microfluidic device ultimately to be applied as a wearable sweat sensor. We show proof-of-principle of the microfluidic functions of the device, namely fluid collection and continuous fluid flow pumping. A filter-paper based layer, that eventually will form the interface between the device and the skin, is used to collect the fluid (e.g., sweat) and enter this into the microfluidic device. A controllable evaporation driven pump is used to drive a continuous fluid flow through a microfluidic channel and over a sensing area. The key element of the pump is a micro-porous membrane mounted at the channel outlet, such that a pore array with a regular hexagonal arrangement is realized through which the fluid evaporates, which drives the flow within the channel. The system is completely fabricated on flexible polyethylene terephthalate (PET) foils, which can be the backbone material for flexible electronics applications, such that it is compatible with volume production approaches like Roll-to-Roll technology. The evaporation rate can be controlled by varying the outlet geometry and the temperature. The generated flows are analyzed experimentally using Particle Tracking Velocimetry (PTV). Typical results show that with 1 to 61 pores (diameter = 250 μm, pitch = 500 μm) flow rates of 7.3 × 10(-3) to 1.2 × 10(-1) μL/min are achieved. When the surface temperature is increased by 9.4°C, the flow rate is increased by 130 %. The results are theoretically analyzed using an evaporation model that includes an evaporation correction factor. The theoretical and experimental results are in good agreement.

No MeSH data available.