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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 flow rate as a function of pore diameter for an evaporation driven flow through an outlet with 37 pores with different pore diameters; the pitch between the pores is kept constant at 500 μm. The experimental values presented are the average and standard deviation values determined from ten recorded videos with duration of one minute. The theoretical values are calculated from evaporation theory
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Fig9: The flow rate as a function of pore diameter for an evaporation driven flow through an outlet with 37 pores with different pore diameters; the pitch between the pores is kept constant at 500 μm. The experimental values presented are the average and standard deviation values determined from ten recorded videos with duration of one minute. The theoretical values are calculated from evaporation theory

Mentions: Furthermore, the influence of the diameter of the pores on the evaporation driven flow rate is studied. A set of pore diameters varying from 50 to 250 μm is used in the evaporation driven flow experiments. The theoretical values can again be estimated by Eqs. 2 to 7. The results are presented in Fig. 9. The flow rate increases when the diameter of the pores gets larger. The relation between the flow rate and diameter of pores is not linear, again due to the reduction of the evaporation correction factor. The experimental data show a good agreement with the theoretical values. Only for the smallest pore diameter, the results deviate. Most probably, this is due to the influence of the vertical pore wall, see Fig. 3a, which is 100 μm high in our measurements, and which becomes more important for smaller pore diameters. As explained in section 3.1, this effect is not accounted for in the theory.Fig. 9


A microfluidic device based on an evaporation-driven micropump.

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

The flow rate as a function of pore diameter for an evaporation driven flow through an outlet with 37 pores with different pore diameters; the pitch between the pores is kept constant at 500 μm. The experimental values presented are the average and standard deviation values determined from ten recorded videos with duration of one minute. The theoretical values are calculated from evaporation theory
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig9: The flow rate as a function of pore diameter for an evaporation driven flow through an outlet with 37 pores with different pore diameters; the pitch between the pores is kept constant at 500 μm. The experimental values presented are the average and standard deviation values determined from ten recorded videos with duration of one minute. The theoretical values are calculated from evaporation theory
Mentions: Furthermore, the influence of the diameter of the pores on the evaporation driven flow rate is studied. A set of pore diameters varying from 50 to 250 μm is used in the evaporation driven flow experiments. The theoretical values can again be estimated by Eqs. 2 to 7. The results are presented in Fig. 9. The flow rate increases when the diameter of the pores gets larger. The relation between the flow rate and diameter of pores is not linear, again due to the reduction of the evaporation correction factor. The experimental data show a good agreement with the theoretical values. Only for the smallest pore diameter, the results deviate. Most probably, this is due to the influence of the vertical pore wall, see Fig. 3a, which is 100 μm high in our measurements, and which becomes more important for smaller pore diameters. As explained in section 3.1, this effect is not accounted for in the theory.Fig. 9

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.