Microfluid applications

In some microfluidic applications liquid is transported with a comparatively low velocity. In such cases, a liquid volume co-moving with the flow experiences inertial forces which are small compared with the viscous forces acting on it. The terms appearing on the left-hand side of Eq. (16) can then be neglected and the creeping flow approximation is valid... 

Gijs, M.A.M., Lacharme, F. and Lehmann, U. (2010) Microfluidic applications of magnetic particles for biological analysis and catalysis. Chemical Reviews, 110 (3), 1518-1563. 

Chabinyc M.L., Chiu D.T., McDonald J.C., Stroock A.D., Christian J.F., Karger A.M., Whitesides G.M., An integrated fluorescence detection system in poly(dimethylsiloxane) for microfluidic applications, Anal. Chem. 2001 73 4491-4498. 

Ohno K, Tachikawa K, Manz A (2008) Microfluidics applications for analytical purposes in chemistry and biochemistry. Electrophoresis 29 4443 1453... 

Biological weed control, 73 331—332 Biologies, manufacture of, 3 826 Biology, microfluidic applications in, 26 968-973... 

M. Pollack, R.B. Fair, and A.D. Shenderov Electrowetting-Based Actuation of Liquid Droplets for Microfluidic Applications. Appl. Phys. Lett. 77(11), 1725... 

Chastek TQ, Beers KL, Amis EJ (2007) Miniaturized dynamic light scattering instrumentation for use in microfluidic applications. Rev Sci Instrum 78 072201... 

K. M. Walsh, and R. S. Keynton, Fully Integrated On-Chip Electrochemical Detection for Capillary Electrophoresis in a Microfabricated Device, Anal. Chem. 2002, 74, 3690 M. L. Chabinyc, D. T. Chiu, J. C. McDonald, A. D. Strook, J. F. Christian, A. M. Karger, and G. M. Whitesides, An Integrated Fluorescence Detection System in Poly(dimethylsiloxane) for Microfluidic Applications, Anal. Chem 2001, 73, 4491. 

For a microfluidic application, a capillary of 10 fim radius and 5 cm length was fabricated in glass. The zeta potential of this glass in 0.01 M KC1 aqueous solution at neutral pH is —30 mV. A potential of 5 V is applied along the capillary. How fast and in which direction does the liquid flow ... 

Silicon is undoubtedly the material which has been most often applied for microfluidic applications, especially in the field of analysis systems. Detailed information has also been obtained for a number of microreactor components and some of them are already commercially available. Even more striking, first experiments with integrated systems have been reported by DuPont [8]. However, silicon components did not find a broad use in industrial applications, especially in the field of synthetic chemistry. For this purpose, future developments have to address a broader variety of components than those mentioned above, including e.g. heat exchangers, extractors and others, and the feasibility of the fabrication of integrated systems has to be demonstrated in more detail. 

Erickson, D., Sinton, D., Li, D.Q., A miniaturized high-voltage integrated power supply for portable microfluidic applications. Labchip 2004, 4, 87-90. 

Conventional solid-state actuators and valves such as peristaltic pumps and solenoid valves require external power and complex fabrication schemes which limit their use in many microfluidic applications. Of particular interest at the moment is the development of low-cost, efficient, polymer-based actuators and valves for sample handling in microfluidics systems. 

M. Barbie, J.J. Mock, A.P. Gray and S. Schultz, Electromagnetic micromotor for microfluidic applications, AppZ. Phys. Lett., 79 (2001) 1399—1401. 

Abstract In sensor and microfluidic applications, the need is to have an adequate solvent resistance of polymers to prevent degradation of the substrate surface upon deposition of sensor formilations, to prevent contamination of the solvent-containing sensor formulations or contamination of organic liquid reactions in microfluidic channels. Unfortunately, no comprehensive quantitative reference solubility data of unstressed copolymers is available to date. In this study, we evaluate solvent-resistance of several polycarbonate copolymers prepared from the reaction of hydroqui-none (HQ), resorcinol (RS), and bisphenol A (BPA). Our high-throughput polymer evaluation approach permitted the construction of detailed solvent-resistance maps, the development of quantitative structure-property relationships for BPA-HQ-RS copolymers and provided new knowledge for the further development of the polymeric sensor and microfluidic components. 

Solvent-resistant polymers are attractive for a variety of microanalytical applications. For chemical sensing, solvent-resistant polymers are important as supports for deposition of solvent-based polymeric sensing formulations.1 Otherwise, a solvent that is used for the preparation of the sensor formulation can attack a plastic substrate of choice forcing the use of either less attractive substrate materials or the use of a complicated sensor-assembly process.2 3 Solvent-resistant polymers also attract interest for microfluidic applications as an alternative to glass and silicon.43 Examples of solvent-resistant polymeric microfluidic systems include those for organic-phase synthesis,6 polymer synthesis,7 studies of polymeric and colloidal... 

Pollack, M.G. Fair, R.B. Shenderov, A.D. Electrowetting-based actuation of liquid droplets for microfluidic applications. Appl. Phys. Lett. 2000, 77 (11), 1725. 

From the 1970s, a large number of imaging studies of non-Brownian suspensions flowing in mm- to cm-sized channels have been performed via Laser Doppler Veiocimetry [120-123] and NMRI [124,125], but little information has been obtained at the single-particle level. Optical microscopy experiments on channel flows of colloids have only recently started to appear, often in relation to microfluidics applications [126]. To avoid image distortions, channels witli square or rectangular cross sections are preferred to cylindrical capillaries. 

The sections below describe three representative capacitive interfaces. The single-ended parallel-plate style is used in inertial and pressure sensors where fabrication constraints preclude a complementary design. Many microfluidic applications, such as particle sorting or fluid level detection, and proximity sensors fall into this category also. Section 6.1.2.3 describes the advantages of complementary interfaces. The last section is devoted to comb style sensors. 

Therefore the emphasis is placed here on the accurate computations of interfacial flows in complex geometries as the complex geometries are ubiquitous in microfluidic applications. For this purpose, the FV/FT method that is designed to compute multiphase flows in complex geometries is first validated against the FD/FT method that can simulate flows only in simple... 

Surfactants are either present as impurities that are difficult to remove from the system or are added deliberately to the bulk fluid to manipulate the interfacial flows [24]. Surfactants may also be created at the interface as a result of chemical reaction between the drop fluid and solutes in the bulk fluid [25, 26]. Surfactants usually reduce the surface tension by creating a buffer layer between the bulk fluid and droplet at the interface. Non-uniform distribution of surfactant concentration creates Marangoni stress at the interface and thus can critically alter the interfacial flows. Surfactants are widely used in numerous important scientific and engineering applications. In particular, surfactants can be used to manipulate drops and bubbles in microchannels [2, 25], and to synthesize micron or submicron size monodispersed drops and bubbles for microfluidic applications [27]. 

Other microfluidic applications based on the manipulation of magnetic microparticles with external permanent magnets have been shown. One example is the ifee-flow magnetophoresis [108, 109], which can be utilized to sort magnetic microparticles by size. 

P. Skafte-Pedersen, D. Sabourin, M. DufVa and D. Snakenborg, Multi-channel peristaltic pump for microfluidic applications featuring monohthic pdms inlay. Lab on a Chip, 9(20), 3003—3006 (2009). 

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