A Brush‐Gel/Metal‐Nanoparticle Hybrid Film as an Efficient Supported Catalyst in Glass Microreactors (original) (raw)
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2000
III CONCLUSIONS 46 REFERENCES 48 APPENDIX 50 iii Abstract The results of a numerical study of the fundamental interactions of engineering design and micromixing on conversion in packed microchannels are presented. Previously, channel-based microreactors made of molded silicon plastic were designed, fabricated, and experimentally tested. These reactors have enzymes immobilized on the channel walls by various methods. They also contain molded packing particles to add reactive surface area and to redistribute the fluid. An intuitive packing arrangement was used in experimental studies and modeled successfully by computer simulation. A computer simulation study was conducted to understand how changes in packing arrangement and number of packing particles affect micromixing and conversion efficiency. The experimental reactors were simulated using CFD-ACE+ multiphysics software. The focus of this study is to optimize the placement and number of packing to more efficiently meet conversion goals, taking into account micro fabrication and operational constraints. Microfluidic fundamentals such as Reynolds number (Re), shear stress, and pressure drop are also explored due to variations in design features. The micro scale dimensions of the channel cross section (125 by 500 micrometers) cause all flows to be laminar. Behavior in the range 0.1 < Re < 100 is examined.
Continuous flow multi-stage microfluidic reactors via hydrodynamic microparticle railing
Lab on a Chip, 2012
Multi-stage'' fluidic reactions are integral to diverse biochemical assays; however, such processes typically require laborious and time-intensive fluidic mixing procedures in which distinct reagents and/or washes must be loaded sequentially and separately (i.e., one-at-a-time). Microfluidic processors that enable multi-stage fluidic reactions with suspended microparticles (e.g., microbeads and cells) to be performed autonomously could greatly extend the efficacy of lab-on-a-chip technologies. Here we present a single-layer microfluidic reactor that utilizes a microfluidic railing methodology to passively transport suspended microbeads and cells into distinct, adjacent laminar flow streams for rapid fluidic mixing and assaying. Four distinct molecular synthesis processes (i.e., consisting of 48 discrete fluidic mixing stages in total) were accomplished on polystyrene microbead substrates (15 mm in diameter) in parallel, without the need for external observation or regulation during device operation. Experimental results also revealed successful railing of suspended bovine aortic endothelial cells (approximately 13 to 17 mm in diameter). The presented railing system provides an effective continuous flow methodology to achieve bead-based and cell-based microfluidic reactors for applications including point-of-care (POC) molecular diagnostics, pharmacological screening, and quantitative cell biology. { Electronic Supplementary Information (ESI) available: Conceptual illustrations and results for device microfabrication, COMSOL Multiphysics models and fluid dynamics simulations, experimental results for limiting diffusion-based mixing and immobilizing select numbers of microbeads within devices, and movies of microbead and cell handling. See
Three-dimensional microchannels as a simple microreactor
Sensors and Actuators B: Chemical, 2009
The aim of this work is the production of a simple and compactable device able to remove hydrocarbons from a gaseous sample. The device is composed of a microstructure, inlet/outlet, heating and detection systems. The microstructure (microreactor) corresponds to a manifold formed by an array of 192 threedimensional microchannels, 40 m wide and 8 mm long each. Microchannels surface was modified by electroless plating copper deposition in order to promote catalysis. The structure can be heated up to 300 • C in a few seconds. The flow mechanisms in the structure and the heating properties were simulated using FEMLAB 3.2b and COSMOS ® 5.0 packages, respectively. The microchannels were exposed to volatile organic compounds during catalysis. An inexpensive tin oxide sensor and correspondent electronic coupled to computer storage data provided detection. Catalysis occurred and could remove at least 10 g of n-hexane in a single batch, but not 2-propanol. This simple miniaturized device is compact, low-cost and can be used not only for sample pretreatment in microanalysis but also in synthesis of new chemical compounds.
Microfluidics Era in Chemistry Field: A Review
Journal of the Indonesian Chemical Society
By miniaturizing the reactor dimension, microfluidic devices are attracting world attention and starting the microfluidic era, especially in the chemistry field because they offer great advantages such as rapid processes, small amount of the required reagents, low risk, ease and accurate control, portable and possibility of online monitoring. Because of that, microfluidic devices have been massively investigated and applied for the real application of human life. This review summarizes the up-to-date microfluidic research works including continuous-flow, droplet-based, open-system, paper-based and digital microfluidic devices. The brief fabrication technique of those microfluidic devices, as well as their potential application for particles separation, solvent extraction, nanoparticle fabrication, qualitative and quantitative analysis, environmental monitoring, drug delivery, biochemical assay and so on, are discussed. Recent perspectives of the microfluidics as a lab-on-chip or mic...
Synthesis of micro and nanostructures in microfluidic systems
Chemical Society Reviews, 2010
In this critical review, we present an overview of the current progress in synthesis of micro and nanostructures by using microfluidics techniques. Emphasis is placed on processes that can be realized on chip, such as polymerization, precipitation, sol-gel, thermolysis and multistep processes. Continuous flow, microfluidic systems show particular promise in controlling size, shape and size distribution of synthesized micro and nanoparticles. Moreover, the use of microfluidics expands the synthesis space (e.g., temperature, pressure, reagents) to conditions not easily accessed in conventional batch procedures and thus, opens new methods for the realization of complex engineered nanostructures and new materials systems. This journal is
Self-powered catalytic microfluidic platforms for fluid delivery
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2017
Catalytic microcapsules, set within a microfluidic lab-on-chip (LOC), function as self-powered micro-pump. An ad-hoc designed LOC is opportunely integrated with a chemically-responsive and flexible thin membrane. During a H2O2 dismutation reaction the membrane is suitably deformed by a gradient of O2 pressure so as to push a flow within a microchannel. The pumping velocity can be finely tuned, depending on reaction rate. Highlights Catalytic capsule-based propellers are incorporated into a microfluidic platform integrating a thin flexible membrane The use of the assembled platform as self-powered catalytic micro-pump is demonstrated A control over fluid injection and transport is achieved by fine-tuning the reaction conditions at the molecular level.
Fab on a Package: LTCC Microfluidic Devices Applied to Chemical Process Miniaturization
Micromachines, 2018
Microfluidics has brought diverse advantages to chemical processes, allowing higher control of reactions and economy of reagents and energy. Low temperature co-fired ceramics (LTCC) have additional advantages as material for fabrication of microfluidic devices, such as high compatibility with chemical reagents with typical average surface roughness of 0.3154 µm, easy scaling, and microfabrication. The conjugation of LTCC technology with microfluidics allows the development of micrometric-sized channels and reactors exploiting the advantages of fast and controlled mixing and heat transfer processes, essential for the synthesis and surface functionalization of nanoparticles. Since the chemical process area is evolving toward miniaturization and continuous flow processing, we verify that microfluidic devices based on LTCC technology have a relevant role in implementing several chemical processes. The present work reviews various LTCC microfluidic devices, developed in our laboratory, applied to chemical process miniaturization, with different geometries to implement processes such as ionic gelation, emulsification, nanoprecipitation, solvent extraction, nanoparticle synthesis and functionalization, and emulsion-diffusion/solvent extraction process. All fabricated microfluidics structures can operate in a flow range of mL/min, indicating that LTCC technology provides a means to enhance micro-and nanoparticle production yield.
A Multiscale Fabrication Approach to Microfluidic System Development
Journal of Manufacturing Processes, 2004
Microfluidic systems for analytical, medical, and sensing applications integrate optical or electrical readouts in lowcost, low-volume consumption systems. Embedding chemically functionalized templates with nanoscale topography within these devices links the scale at which molecular recognition/self-organization occurs and the macroscopic layout of fluid channels, mixing volumes, and detection regions. Although the design of a platform that would meet the needs of all microfluidic experiments is a difficult undertaking, this paper provides a description of a flexure-based platform that may address generic requirements such as low cost, ease of manufacture, and repeatable alignment/sealing performance. Experimental results are provided for master replication in plastics by hot embossing and a microfluidic platform that orients 125 micrometer channels embossed in a poly(vinyl chloride) gasket to an array of high-speed machined channels.