Toronto, Canada
Toronto, Canada

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Hof L.A.,Concordia University at Montréal | Guo X.,FlowJEM Inc. | Seo M.,FlowJEM Inc. | Wuthrich R.,Concordia University at Montréal | And 3 more authors.
Micromachines | Year: 2017

As the field of microelectromechanical systems (MEMS) matures, new demands are being placed on the microfabrication of complex architectures in robust materials, such as hard plastics. Iterative design optimization in a timely manner-rapid prototyping-places challenges on template fabrication, for methods such as injection moulding and hot embossing. In this paper, we demonstrate the possibility of using spark assisted chemical engraving (SACE) to produce micro patterned glass templates. The direct, write-based approach enabled the facile fabrication of smooth microfeatures with variations in all three-dimensions, which could be replicated by hot embossing different thermoplastics. As a proof of principle, we demonstrated the technique for a high glass transition temperature polycarbonate. Good fidelity over more than 10 cycles provides evidence that the approach is viable for rapid prototyping and has the potential to satisfy commercial-grade production at medium-level output volumes. Glass imprint templates showed no degradation after use, but care must be taken due to brittleness. The technique has the potential to advance microfabrication needs in academia and could be used by MEMS product developers. © 2017 by the authors.


Greener J.,University of Toronto | Greener J.,FlowJEM Inc | Tumarkin E.,University of Toronto | Debono M.,University of Toronto | And 3 more authors.
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2012

We demonstrate continuous flow acid-base titration reactions as an educational microfluidic platform for undergraduate and graduate analytical chemistry courses. A series of equations were developed for controlling and predicting the results of acid-base neutralisation reactions conducted in a microfluidic format, including the combinations of (i) a strong base and a strong acid, (ii) a strong base and a weak acid, and (iii) a strong base and a multiprotic acid. Microfluidic titrations yielded excellent repeatability. The small experimental footprint is advantageous in crowded teaching laboratories, and it offers limited waste and exposure to potentially hazardous acids and bases. This platform will help promote the utilisation of microfluidics at an earlier stage of students' careers. © 2012 The Royal Society of Chemistry.


Voicu D.,University of Toronto | Scholl C.,University of Toronto | Li W.,University of Toronto | Jagadeesan D.,University of Toronto | And 5 more authors.
Macromolecules | Year: 2012

We report a high-throughput study of the kinetics of a multicomponent polymerization reaction in a microfluidic reactor integrated with in situ attenuated total reflection Fourier transform infrared spectroscopy. The technique was used to study the kinetics of an exemplary free-radical polymerization reaction of N-isopropylacrylamide, which was initiated by ammonium persulfate in the presence of the accelerator N,N,N′,N′- tetramethylethylenediamine in water. By monitoring the rate of disappearance of the monomer double bonds, we determined the effects of the concentration of the monomer, initiator, and accelerator on the rate of polymerization and the effect of the pH of the reaction system on the reaction kinetics. This work opens the way for the kinetic studies of complex polymer systems in a microfluidic format. © 2012 American Chemical Society.


Greener J.,University of Toronto | Greener J.,FlowJem Inc. | Tumarkin E.,University of Toronto | Debono M.,University of Toronto | And 6 more authors.
Analyst | Year: 2012

We report the development of a versatile microfluidic (MF) reactor with multiple analytical probes, which can be used for (i) quantitative characterisation of molecular vibrational signatures of reactants or products, (ii) the localised real-time monitoring of temperature and (iii) site-specific measurements of pH of the reaction system. The analytical probes utilised for in situ reaction analysis include an ATR-FTIR probe, a temperature probe, and a pH probe. We demonstrate the applications of the MF reactor with integrated probes for the parallel monitoring of multiple variables in acid/base neutralisation reaction, of changes in buffer pH, temperature, and vibrational absorption bands, and for monitoring the kinetics of the reaction between CO 2 and a buffer system with therapeutic applications. © 2012 The Royal Society of Chemistry.


PubMed | University of Toronto, FlowJEM Inc. and Laval University
Type: Journal Article | Journal: Sensors (Basel, Switzerland) | Year: 2016

We build on the concept of hot intrusion embossing to develop a one-step fabrication method for thermoplastic microfluidic channels containing integrated three-dimensional features. This was accomplished with simple, rapid-to-fabricate imprint templates containing microcavities that locally control the intrusion of heated thermoplastic based on their cross-sectional geometries. The use of circular, rectangular and triangular cavity geometries was demonstrated for the purposes of forming posts, multi-focal length microlense arrays, walls, steps, tapered features and three-dimensional serpentine microchannels. Process variables, such as temperature and pressure, controlled feature dimensions without affecting the overall microchannel geometry. The approach was demonstrated for polycarbonate, cycloolefin copolymer and polystyrene, but in principle is applicable to any thermoplastic. The approach is a step forward towards rapid fabrication of complex, robust, microfluidic platforms with integrated multi-functional elements.

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