Efficient mixing of viscoelastic fluids in a microchannel at low Reynolds number

Gan, Hiong Yap; Lam, Yee Cheong; Nguyen, Nam‐Trung; Tam, Kam Chiu; Yang, Chun

doi:10.1007/s10404-006-0109-4

Cited by 69 publications

(85 citation statements)

References 13 publications

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“…Due to laminar flow in our experimental conditions (Reynolds number Re < 1) [59], mixing between the two adjacent streams happens only by diffusion. With increasing length of the channel the streams have more time to interact and one can observe the development of a concentration profile at the interface between the streams over time.…”

Section: (D-e) and Supplementary Information)mentioning

confidence: 98%

The performance of 2D array detectors for light sheet based fluorescence correlation spectroscopy

et al. 2013

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Abstract:Single plane illumination microscopy based fluorescence correlation spectroscopy (SPIM-FCS) is a new method for imaging FCS in 3D samples, providing diffusion coefficients, transport, flow velocities and concentrations in an imaging mode. SPIM-FCS records correlation functions over a whole plane in a sample, which requires array detectors for recording the fluorescence signal. Several types of image sensors are suitable for FCS. They differ in properties such as effective area per pixel, quantum efficiency, noise level and read-out speed. Here we compare the performance of several low light array detectors based on three different technologies: (1) Single-photon avalanche diode (SPAD) arrays, (2) passive-pixel electron multiplying charge coupled device (EMCCD) and (3) active-pixel scientific-grade complementary metal oxide semiconductor cameras (sCMOS). We discuss the influence of the detector characteristics on the effective FCS observation volume, and demonstrate that light sheet based SPIM-FCS provides absolute diffusion coefficients. This is verified by parallel measurements with confocal FCS, single particle tracking (SPT), and the determination of concentration gradients in space and time. While EMCCD cameras have a temporal resolution in the millisecond range, sCMOS cameras and SPAD arrays can extend the time resolution of SPIM-FCS down to 10 μs or lower. References and links1. K. M. Berland, P. T. So, and E. Gratton, "Two-photon fluorescence correlation spectroscopy: method and application to the intracellular environment," Biophy. J. 68, 694-701 (1995). 2. P. Schwille, U. Haupts, S. Maiti, and W. W. Webb, "Molecular dynamics in living cells observed by fluorescence correlation spectroscopy with one-and two-photon excitation," Biophy. J. 77, 2251-2265 (1999). 3. R. Brock, G. Vàmosi, G. Vereb, and T. M. Jovin, "Rapid characterization of green fluorescent protein fusion proteins on the molecular and cellular level by fluorescence correlation microscopy," Proc. Natl. Acad. Sci. U.S.A. 96, 10123-10128 (1999 0-1 (2010). 53. Z. Petrásek, P. Schwille, and Z. Petrášek, "Precise measurement of diffusion coefficients using scanning fluorescence correlation spectroscopy," Biophy.

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Section: (D-e) and Supplementary Information)mentioning

confidence: 98%

The performance of 2D array detectors for light sheet based fluorescence correlation spectroscopy

et al. 2013

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“…The formation of these asymmetrical vortices based on empirical observations was discussed in our previous works. 15,16 Figure 4 presents the consecutive velocity fields of viscoelastic two-fluid flow at Q =10 ml/ h ͑De= 434.6 and Re= 0.02͒. Salient and large corner vortices with viscoelastic "whipping" at upstream of the contraction were evident.…”

Section: A Measurement Of the Velocity Fieldmentioning

confidence: 99%

“…15,16 We have reported our experimental observations of streak flow in silicon-glass microchip. 16 Our mixing experiments have very high values of elasticity numbers ͑a ratio of elastic to inertial forces of the system͒, which are approximately 932 and 5070. At such a high elasticity number, inertial effects were negligible.…”

Section: Introductionmentioning

confidence: 99%

Micromixer based on viscoelastic flow instability at low Reynolds number

et al. 2009

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We exploited the viscoelasticity of biocompatible dilute polymeric solutions, namely, dilute poly͑ethylene oxide͒ solutions, to significantly enhance mixing in microfluidic devices at a very small Reynolds number, i.e., ReϷ 0.023, but large Peclet and elasticity numbers. With an abrupt contraction microgeometry ͑8:1 contraction ratio͒, two different dilute poly͑ethylene oxide͒ solutions were successfully mixed with a short flow length at a relatively fast mixing time of Ͻ10 s. Microparticle image velocimetry was employed in our investigations to characterize the flow fields. The increase in velocity fluctuation with an increase in flow rate and Deborah number indicates the increase in viscoelastic flow instability. Mixing efficiency was characterized by fluorescent concentration measurements. Our results showed that enhanced mixing can be achieved through viscoelastic flow instability under situations where molecular-diffusion and inertia effects are negligible. This approach bypasses the laminar flow limitation, usually associated with a low Reynolds number, which is not conducive to mixing.

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“…19 According to Eq. ͑4͒ and for the given geometries W = 200 m, H =50 m, the elasticity number in our experiment is El= 1690 in the case of 15°structure and El= 611 in the case of other opening angles.…”

Section: -4 Nguyen Et Al Biomicrofluidics 2 034101 ͑2008͒mentioning

confidence: 99%

Improvement of rectification effects in diffuser/nozzle structures with viscoelastic fluids

Nguyen

Lam

et al. 2008

Biomicrofluidics

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This paper reports the improvement of rectification effects in diffuser/nozzle structures with viscoelastic fluids. Since rectification in a diffuser/nozzle structure with Newtonian fluids is caused by inertial effects, micropumps based on this concept require a relatively high Reynolds numbers and high pumping frequencies. In applications with relatively low Reynolds numbers, anisotropic behavior can be achieved with viscoelastic effects. In our investigations, a solution of dilute polyethylene oxide was used as the viscoelastic fluid. A microfluidic device was fabricated in silicon using deep reactive ion etching. The microfluidic device consists of access ports for pressure measurement, and a series of ten diffuser/nozzle structures. Measurements were carried out for diffuser/nozzle structures with opening angles ranging from 15°to 60°. Flow visualization, pressure drop and diodicity of de-ionized water and the viscoelastic fluid were compared and discussed. The improvement of diodicity promises a simple pumping concept at low Reynolds numbers for lab-on-a-chip applications.

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Efficient mixing of viscoelastic fluids in a microchannel at low Reynolds number

Cited by 69 publications

References 13 publications

The performance of 2D array detectors for light sheet based fluorescence correlation spectroscopy

The performance of 2D array detectors for light sheet based fluorescence correlation spectroscopy

Micromixer based on viscoelastic flow instability at low Reynolds number

Improvement of rectification effects in diffuser/nozzle structures with viscoelastic fluids

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