| 1. |
- Carlborg, Carl Fredrik, et al.
(author)
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Continuous flow switching by pneumatic actuation of the air lubrication layer on superhydrophobic microchannel walls
- 2008
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In: 21st IEEE International Conference on Micro Electro Mechanical Systems (IEEE MEMS 2008). - : IEEE conference proceedings. - 9781424417926 ; , s. 599-602
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Conference paper (peer-reviewed)abstract
- This paper introduces and experimentally verifies a method for robust, active control of friction reduction in microchannels, enabling new flow control applications and overcoming previous limitations with regard to sustainable liquid pressure. The air pockets trapped at asuperhydrophobic micrograting during liquid priming are coupled to an actively controlled pressure source, allowing the pressure difference over the air/liquid interface to be dynamically adjusted. This allows for manipulating the friction reduction properties of the surface, enabling active control of liquid mass flow through the channel. It also permits for sustainable air lubrication at theoretically unlimited liquid pressures, without loss of superhydrophobic properties. With the non-optimized grating used in the experiment, a difference in liquid mass flow of 4.8 % is obtained by alternatively collapsing and recreating the air pockets using the coupled pressure source, which is in line with a FE analysis of the same geometry. A FE analysis of a more optimized geometry predicts a mass flow change of over 30%, which would make possible new microfluidic devices based on local friction control. It is also experimentally shown that our method allows for sustainable liquid pressure 3 times higher than the Laplace pressure of a passive device.
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| 2. |
- Carlborg, Carl Fredrik, et al.
(author)
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LARGE SCALE INTEGRATED 3D MICROFLUIDIC NETWORKS THROUGH HIGH YIELD FABRICATION OF VERTICAL VIAS IN PDMS
- 2010
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In: MEMS 2010. - : IEEE conference proceedings. - 9781424457649 ; , s. 240-243
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Conference paper (peer-reviewed)abstract
- This paper introduces a robust, high yield, single-step fabrication method for creating densely spaced, miniaturized out-of-plane fluidic interconnecting channels (=vias) in standard poly(dimethylsiloxane) PDMS. Unblocked vias are essential for creating 3D microfluidic networks. Previously reported methods either had low yield, because of residual membranes covering the vias after polymerization, or required complicated extra steps to remove the blocking membranes.In contrast, our method prevents the formation of residual membranes by inhibition of the polymerization on top of the protuding mold features defining the vias locations. In addition to providing unblocked vias, the inhibition also leaves a flat partially cured, sticky top surface that adheres well to other surfaces and allows self-sealing stacking of several PDMS layers. We demonstrate the new method by manufacturing a densely perforated PDMS membrane and a large scale integrated (LSI) 3D PDMS microfluidic channel network. Our method enables batch manufacturing of complex fluidic devices by speeding up and simplifying the fabrication of complex microfluidic components in standard PDMS.
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| 3. |
- Carlborg, Carl Fredrik, et al.
(author)
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Microchannels with substantial friction reduction at large pressure and large flow
- 2009
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In: Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems. ; , s. 39-42
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Conference paper (peer-reviewed)abstract
- This paper introduces and experimentally verifies a self-regulating method for reducing the friction losses in large microchannels at high liquid pressures and large liquid flows, overcoming limitations with regard to sustainable liquid pressure on a superhydrophobic surface. Our design of the superhydrophobic channel creates an automatic adjustment of the gas pressure in the lubricating air layer to the local liquid pressure in the channel. This is achieved by pneumatically connecting the liquid in the microchannel to the air pockets trapped at channel wall trough a pressure feedback channel. When liquid enters the feedback channel it compresses the air and increases the pressure in the air pocket. This reduces the pressure drop over the air-liquid interface and increases the maximum sustainable liquid pressure. We define a dimensionless fluidic number, WF = PLDh/ ?cos?C, which expresses the fluidic energy carrying capacity of a superhydrophobic microchannel. We experimentally verified that our geometry can sustain several times higher liquid pressure before collapsing, and we measured better friction reducing properties at higher WF values than in previous works. This method could be applicable for reducing near-wall laminar friction in both micro-and macroscale flows.
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| 4. |
- Carlborg, Carl Fredrik, 1981-, et al.
(author)
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RELIABLE BATCH MANUFACTURING OF MINIATURIZED VERTICAL VIAS IN SOFT POLYMER REPLICA MOLDING
- 2007
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In: 11th International Conference on Miniaturized Systems for Chemistry and Life Sciences (microTAS 2007). ; , s. 527-529
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Conference paper (peer-reviewed)abstract
- We introduce and have successfully tested an uncomplicated polydimethylsiloxane (PDMS) compatible method for batch manufacturing vertical microfluidic interconnects via a surface inhibition of cationic photopolymerization. The yield of the maskless method is 100%. Moreover, the method enhances bond strength with subsequently laminated polymer layers.
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| 5. |
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| 6. |
- Gylfason, Kristinn B., 1978-, et al.
(author)
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A packaged optical slot-waveguide ring resonator sensor array for multiplex assays in labs-on-chip
- 2009
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In: Proceedings of Conference, MicroTAS 2009 - The 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - : Chemical and Biological Microsystems Society. - 9780979806421 ; , s. 2004-2006
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Conference paper (peer-reviewed)abstract
- We present the design, fabrication, and characterization of a packaged array of individually addressable slot-waveguide ring resonator sensors in a compact cartridge for sensitive, label-free, multiplex assays. The novel use of a dual surfaceenergy adhesive film enables simple generic packaging method for multiple sensors in a single cartridge. The use of optical slot-waveguides, and drift compensation by on-chip light splitting to reference sensors, gives the best refractive-index limit of detection reported for planar ring resonator sensors.
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| 8. |
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| 9. |
- Hill, Daniel, et al.
(author)
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Microfluidic and Transducer Technologies for Lab on a Chip Applications
- 2010
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In: 2010 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC). - : IEEE conference proceedings. - 9781424441242 ; , s. 305-307
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Conference paper (peer-reviewed)abstract
- Point-of-care diagnostic devices typically require six distinct qualities: they must deliver at least the same sensitivity and selectivity, and for a cost per assay no greater than that of today's central lab technologies, deliver results in a short period of time (<15 min at GP; <2h in hospital), be portable or at least small in scale, and require no or extremely little sample preparation. State-of-the-art devices deliver information of several markers in the same measurement.
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