Design and fabrication of microfluidic devices for multiphase mixing and reaction

Losey, Matthew W.; Jackman, Rebecca J.; Firebaugh, Samara L.; Schmidt, Martin; Jensen, Klavs F.

doi:10.1109/jmems.2002.803416

Cited by 222 publications

(186 citation statements)

References 39 publications

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“…Such phase diagrams have been often presented in the coordinates of velocities (or volumetric flow rates) of the two fluids [2,4,7,22]. We have replotted the data shown in Fig.…”

Section: Forming Plugs Of Solutions With Viscosity Higher Than Watermentioning

confidence: 99%

Effects of viscosity on droplet formation and mixing in microfluidic channels

Tice

Lyon

Ismagilov

2004

Analytica Chimica Acta

326

254

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This paper characterizes the conditions required to form nanoliter-sized droplets (plugs) of viscous aqueous reagents in flows of immiscible carrier fluid within microfluidic channels. For both non-viscous (viscosity of 2.0 mPa s) and viscous (viscosity of 18 mPa s) aqueous solutions, plugs formed reliably in a flow of water-immiscible carrier fluid for Capillary number less than 0.01, although plugs were able to form at higher Capillary numbers at lower ratios of the aqueous phase flow rate to the flow rate of the carrier fluid (in all the experiments performed, the Reynolds number was less than 1). The paper also shows that combining viscous and non-viscous reagents can enhance mixing in droplets moving through straight microchannels by providing a nearly ideal initial distribution of reagents within each droplet. The study should facilitate the use of this droplet-based microfluidic platform for investigation of protein crystallization, kinetics, and assays.

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“…Such phase diagrams have been often presented in the coordinates of velocities (or volumetric flow rates) of the two fluids [2,4,7,22]. We have replotted the data shown in Fig.…”

Section: Forming Plugs Of Solutions With Viscosity Higher Than Watermentioning

confidence: 99%

Effects of viscosity on droplet formation and mixing in microfluidic channels

Tice

Lyon

Ismagilov

2004

Analytica Chimica Acta

326

254

View full text Add to dashboard Cite

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“…Heterogenized catalysts can also contribute to the rapidly advancing area of studying catalyzed reactions with NMR micro-fluidic technology [122,154]. For example, a porous silicon layer supporting the catalyst and etched in the form of a micro-channel can simulate a catalytic microreactor [105], allowing the possibility of investigating multiphase reactions in the silicon chip. It should also be mentioned that heterogeneously catalyzed para-hydrogenations can, just as their homogeneous counterparts, lead to enhanced signals on other nuclei.…”

Section: Discussionmentioning

confidence: 99%

MRI of Heterogeneous Hydrogenation Reactions Using Parahydrogen Polarization

Burt

2008

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The power of magnetic resonance imaging (MRI) is its ability to image the internal structure of optically opaque samples and provide detailed maps of a variety of important parameters, such as density, diffusion, velocity and temperature. However, one of the fundamental limitations of this technique is its inherent low sensitivity. For example, the low signal to noise ratio (SNR) is particularly problematic for imaging gases in porous materials due to the low density of the gas and the large volume occluded by the porous material. This is unfortunate, as many industrially relevant chemical reactions take place at gas-surface interfaces in porous media, such as packed catalyst beds. Because of this severe SNR problem, many techniques have been developed to directly increase the signal strength. These techniques work by manipulating the nuclear spin populations to produce polarized (i.e. non-equilibrium) states with resulting signal strengths that are orders of magnitude larger than those available at thermal equilibrium. 2This dissertation is concerned with an extension of a polarization technique based on the properties of parahydrogen. Specifically, I report on the novel use of heterogeneous catalysis to produce parahydrogen induced polarization and applications of this new technique to gas phase MRI and the characterization of micro-reactors. First, I provide an overview of nuclear magnetic resonance (NMR) and how parahydrogen is used to improve the SNR of the NMR signal. I then present experimental results demonstrating that it is possible to use heterogeneous catalysis to produce parahydrogen-induced polarization.These results are extended to imaging void spaces using a parahydrogen polarized gas. In the second half of this dissertation, I demonstrate the use of parahydrogen-polarized gasphase MRI for characterizing catalytic microreactors. Specifically, I show how the improved SNR allows one to map parameters important for characterizing the heat and mass transport in a heterogeneous catalyst bed. This is followed by appendices containing detailed

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“…The applications of this area are too vast and some of the applications are belongs to cartelistic reactors [2,3] , Tissue Engineering [4] , Multiphase mixing and reaction [5] , Blood Flow and the drug reaction [6] , highthroughput screening in drug development [9,10] , bio-analyses [11] , examination and manipulation of samples consisting of a single cell [12,13] , and also in efficient heat sinks [8] . But one of the main applications of this field is the extraction process.…”

Section: Recently the Area Microfluidics Is Related To Chemicalmentioning

confidence: 99%