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  • 1.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microfluidics at High Pressures: Understanding, Sensing, and Control2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis explores understanding, sensing, and control in high-pressure microfluidics. The high-pressure regime allows fluids to be forced through narrow channels at substantial speed and creates conditions for fluids of high density and low viscosity—features desired in flow-based chemical analyses. With changes to pressure and temperature, fluid properties vary, and for miniaturized flow systems, sensing and control are needed.

    For miniaturized chemical analytics to utilize high-pressure fluids, like supercritical CO2, sensors are required for flow characterization. In this thesis, high-pressure tolerant sensors in glass chips have been developed and investigated. By the use of chip-integrated temperature, flow, and relative permittivity sensors, the variable behavior of supercritical CO2 or binary component CO2-alcohol mixtures have been investigated. To be able to change flow rates, a heat-based actuator chip has been developed. By a flow control system, which combines a relative permittivity sensor and heat actuated flow regulators on a modular system, the composition of binary component CO2-alcohol mixtures can be tuned and controlled with feedback.

    Flows of multiphase CO2-H2O hold promise for miniaturized extraction systems. In this thesis, parallel multiphase CO2-H2O flow has been studied. To achieve control, methods have been investigated where channels have been modified by the introduction of a guiding ridge and altered by a chemical coating. Flow is a dynamic process, where pressure and temperature can vary with time and place. As the properties of fluids containing CO2 may change with pressure and temperature, properties will also change with time and place. Because of this, instruments with spatial and temporal resolution are needed to better understand dynamic chemical effects at flow. In this thesis, a tool is presented to study the dynamic acidification of aqueous solutions that come in contact with flowing CO2.

    By a study performed to understand the strength and pressure tolerance of glass chips, it has been found that the fracture is not only determined by the applied pressure, but also on time and environment.

    List of papers
    1. Fracture strength of glass chips for high-pressure microfluidics
    Open this publication in new window or tab >>Fracture strength of glass chips for high-pressure microfluidics
    2016 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 26, no 9, article id 095009Article in journal (Refereed) Published
    Abstract [en]

    High-pressure microfluidics exposes new areas in chemistry. In this paper, the reliability of transparent borosilicate glass chips is investigated. Two designs of circular cavities are used for fracture strength tests, either 1.6 mm wide with rounded corners to the fluid inlets, or 2.0 mm wide with sharp inlet corners. Two kinds of tests are done, either short-term,e.g. pressurization to fracture at room temperature, or long-term, with fracture at constant pressurization for up to one week, in the temperature region 11–125 °C. The speed of crack fronts is measured using a high-speed camera. Results show fracture stresses in the range of 129 and 254 MPa for short-term measurements. Long-term measurements conclude the presences of a temperature and stress dependent delayed fracture. For a reliability ofone week at 11–38 °C, a pressure limit is found at the lower end of the short-term measurements, or 15% lower than the average. At 80 °C, this pressure limit is 45% lower. Crack speeds are measured to be 10−5 m s-1 during short-term fracture. These measurements are comparable with estimations based on slow crack growth and show that the growth affects the reliability of glass chips. This effect is strongly affected by high temperatures, thus lowers the operating window of high-pressure glass microfluidic devices.

    Keywords
    glass, fracture strength, high pressure microfluidics, crack growth, temperature dependence
    National Category
    Other Engineering and Technologies not elsewhere specified
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-309983 (URN)10.1088/0960-1317/26/9/095009 (DOI)000402408400009 ()
    Funder
    Swedish Research Council, 2011:5037Knut and Alice Wallenberg Foundation
    Available from: 2016-12-08 Created: 2016-12-08 Last updated: 2018-06-19Bibliographically approved
    2. Influence of flow rate, temperature and pressure on multiphase flows of supercritical carbon dioxide and water using multivariate partial least square regression
    Open this publication in new window or tab >>Influence of flow rate, temperature and pressure on multiphase flows of supercritical carbon dioxide and water using multivariate partial least square regression
    Show others...
    2015 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 10, article id 105001Article in journal (Refereed) Published
    Abstract [en]

    Supercritical carbon dioxide (scCO2) is often used to replace harmful solvents and can dissolve a wide range of organic compounds. With a favorable critical point at 31 °C and 7.4 MPa, reaching above the critical point for scCO2 is fairly accessible. Because of the compressible nature of scCO2 and the large changes of viscosity and density with temperature and pressure, there is a need to determine the behavior of scCO2 in microfluidic systems. Here, the influence of how parameters such as flow rate, temperature, pressure, and flow ratio affects the length of parallel flow of water and scCO2 and the length of the created CO2 segments are investigated and modeled using multivariate data analysis for a 10 mm long double-y channel. The parallel length and segment size were observed in the laminar regime around and above the critical point of CO2. The flow ratio between the two fluids together with the flow rate influenced both the parallel length and the segment sizes, and a higher pressure resulted in shorter parallel lengths. Regarding the segment length of CO2, longer segments were a result of a higher Weber number for H2O together with a higher temperature in the channel. 

    Keywords
    Supercritical fluids, microfluidics, carbon dioxide, partial least square regression, principal component analysis, fluid dynamics, multiphase flow
    National Category
    Engineering and Technology Other Materials Engineering
    Identifiers
    urn:nbn:se:uu:diva-253552 (URN)10.1088/0960-1317/25/10/105001 (DOI)000366827400017 ()
    Funder
    Swedish Research Council, 2011-5037Knut and Alice Wallenberg Foundation
    Available from: 2015-05-29 Created: 2015-05-29 Last updated: 2018-06-19Bibliographically approved
    3. Influence of surface modifications and channel structure for microflows of supercritical carbon dioxide and water
    Open this publication in new window or tab >>Influence of surface modifications and channel structure for microflows of supercritical carbon dioxide and water
    2016 (English)In: Journal of Supercritical Fluids, ISSN 0896-8446, E-ISSN 1872-8162, Vol. 107, p. 649-656Article in journal (Refereed) Published
    Abstract [en]

    Miniaturization offers a possibility to increase the performance and decrease the time scales of systems. Existing microsystems using supercritical CO2 mainly utilizes multiphase segmented flows. To allow for a broader toolbox for future systems, also parallel flows are useful which eases the separation of the different phases. Here, the effect of different surface coatings are studied for multiphase flows of scCO2 and H2O in flat microchannels, with and without a 4 μm high ridge guide, which allows for pinning of the fluid interface inside the 190 μm wide and 35 μm high channel. Three different surfaces with different wettings towards scCO2 and H2O are studied, where a surface terminated with a hydrocarbon-based silane was observed to be neutral in the H2O/scCO2 system, a surface terminated with a fluorocarbon-based silane was hydrophobic, and an uncoated glass surface was hydrophilic.

    Using two flow rates of 5:5 μl/min (CO2:H2O) and 6.5:3.5 μl/min (CO2:H2O), a parallel flow between scCO2 and H2O was observed for uncoated and flat channels where the H2O flow pushed the CO2 to the side, before the flows eventually breaks up into segments. With a ridge guide in the middle of the channel, the interface was pinned at half the channel width, although still breaking up into segments. The neutral hydrocarbon-based surface coating with approximately 90° contact angles resulted in evenly created segments without a ridge guide. Including a guide in the middle of the channel, a parallel flow was observed throughout the channel, although occasionally small CO2 segments entered the H2O outlet. Using the fluorocarbon-based silane resulted in an unstable segmented system with pressure fluctuations.

    Using surface modifications, an increased control can be achieved for either segmentation or parallel flow where a neutral surface is favored for a stable flow behavior. Together with a ridge guide, the fluid interface was pinned at the center. 

    Keywords
    Microfluidics, Supercritical CO2, Silane coating, Parallel flow, Segmented flow, Surface modification
    National Category
    Engineering and Technology Chemical Engineering
    Identifiers
    urn:nbn:se:uu:diva-253554 (URN)10.1016/j.supflu.2015.07.027 (DOI)000366077100077 ()
    Funder
    Swedish Research Council, 2011-5037Knut and Alice Wallenberg Foundation
    Available from: 2015-05-29 Created: 2015-05-29 Last updated: 2018-06-19Bibliographically approved
    4. Thin film metal sensors in fusion bonded glass chips for high-pressure microfluidics
    Open this publication in new window or tab >>Thin film metal sensors in fusion bonded glass chips for high-pressure microfluidics
    Show others...
    2017 (English)In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 27, no 1, article id 015018Article in journal (Refereed) Published
    Abstract [en]

    High-pressure microfluidics offers fast analyses of thermodynamic parameters for compressed process solvents. However, microfluidic platforms handling highly compressible supercritical CO2 are difficult to control, and on-chip sensing would offer added control of the devices. Therefore, there is a need to integrate sensors into highly pressure tolerant glass chips. In this paper, thin film Pt sensors were embedded in shallow etched trenches in a glass wafer that was bonded with another glass wafer having microfluidic channels. The devices having sensors integrated into the flow channels sustained pressures up to 220 bar, typical for the operation of supercritical CO2. No leakage from the devices could be found. Integrated temperature sensors were capable of measuring local decompression cooling effects and integrated calorimetric sensors measured flow velocities over the range 0.5-13.8 mm/s. By this, a better control of high-pressure microfluidic platforms has been achieved.

    Keywords
    supercritical carbon dioxide, high pressure microfluidics, integrated electrodes, temperature sensing, flow sensing, glass
    National Category
    Other Engineering and Technologies not elsewhere specified
    Research subject
    Engineering Science with specialization in Microsystems Technology
    Identifiers
    urn:nbn:se:uu:diva-310063 (URN)10.1088/0960-1317/27/1/015018 (DOI)000388703300003 ()
    Funder
    Swedish Research Council, 2011-5037VINNOVAKnut and Alice Wallenberg Foundation
    Note

    Part financed through Swedish Agency for the Innovation System, Vinnova, through the Centre for Natural Disaster Science (CNDS)

    Available from: 2016-12-09 Created: 2016-12-09 Last updated: 2018-06-19Bibliographically approved
    5. A microfluidic relative permittivity sensor for feedback control of carbon dioxide expanded liquid flows
    Open this publication in new window or tab >>A microfluidic relative permittivity sensor for feedback control of carbon dioxide expanded liquid flows
    2019 (English)In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 285, p. 165-172Article in journal (Refereed) Published
    Abstract [en]

    Binary CO2-alcohol mixtures, such as CO2-expanded liquids (CXLs), are promising green solvents for reaching higher performance in flow chemistry and separation processing. However, their compressibility and high working pressure makes handling challenging. These mixtures allow for a tuneable polarity but, to do so, requires precise flow control. Here, a high-pressure tolerant microfluidic system containing a relative permittivity sensor and a mixing chip is used to actively regulate the relative permittivity of these fluids and indirectly—composition. The sensor is a fluid-filled plate capacitor created using embedded 3D-structured thin films and has a linearity of 0.9999, a sensitivity of 4.88 pF per unit of relative permittivity, and a precision within 0.6% for a sampling volume of 0.3 μL. Composition and relative permittivity of CO2-ethanol mixtures were measured at 82 bar and 21 °C during flow. By flow and dielectric models, this relationship was found to be described by the pure components and a quadratic mixing rule with an interaction parameter, kij, of -0.63 ± 0.02. Microflows with a relative permittivity of 1.7–21.4 were generated, and using the models, this was found to correspond to compositions of 6–90 mol % ethanol in CO2. With the sensor, a closed loop control system was realised and CO2-ethanol flows were tuned to setpoints of the relative permittivity in 30 s.

    Keywords
    Relative permittivity, Process control, CO2-expanded liquids, Binary fluid mixtures, High-pressure microfluidics
    National Category
    Chemical Engineering Other Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:uu:diva-353945 (URN)10.1016/j.sna.2018.11.015 (DOI)000456902600021 ()
    Funder
    Knut and Alice Wallenberg Foundation
    Available from: 2018-06-19 Created: 2018-06-19 Last updated: 2019-02-25Bibliographically approved
    6. A microfluidic control board for high-pressure flow, composition, and relative permittivity
    Open this publication in new window or tab >>A microfluidic control board for high-pressure flow, composition, and relative permittivity
    2018 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 90, no 21, p. 12601-12608Article in journal (Refereed) Published
    Abstract [en]

    Flow control is central to microfluidics and chromatography. With decreasing dimensions and high pressures, precise fluid flows are often needed. In this paper, a high-pressure flow control system is presented, allowing for the miniaturization of chromatographic systems and the increased performance of microfluidic setups by controlling flow, composition and relative permittivity of two-component flows with CO2. The system consists of four chips: two flow actuator chips, one mixing chip and one relative permittivity sensor. The actuator chips, throttling the flow, required no moving parts as they instead relied on internal heaters to change the fluid resistance. This allows for flow control using miniaturized fluid delivery systems containing only a single pump or pressure source. Mobile phase gradients between 49% to 74% methanol in CO2 were demonstrated. Depending on how the actuator chips were dimensioned, the position of this range could be set for different method-specific needs. With the microfluidic control board, both flow and composition could be controlled from constant pressure sources, drift could be removed, and variations in composition could be lowered by 84%, resulting in microflows of CO2 and methanol with a variation in the composition of 0.30%.

    National Category
    Chemical Engineering
    Identifiers
    urn:nbn:se:uu:diva-353953 (URN)10.1021/acs.analchem.8b02758 (DOI)000449722500039 ()30269500 (PubMedID)
    Funder
    Knut and Alice Wallenberg Foundation
    Available from: 2018-06-19 Created: 2018-06-19 Last updated: 2018-12-21Bibliographically approved
    7. Dynamic pH determination at high pressure of aqueous additive mixtures in contact with dense CO2
    Open this publication in new window or tab >>Dynamic pH determination at high pressure of aqueous additive mixtures in contact with dense CO2
    Show others...
    2018 (English)In: Journal of Supercritical Fluids, ISSN 0896-8446, E-ISSN 1872-8162, Vol. 136, p. 95-101Article in journal (Refereed) Published
    Abstract [en]

    A system consisting of a high-pressure tolerant microfluidic glass chip, high-speed absorbance imaging, and image processing has been developed to study rapid dynamic events like pH change in a multiphase flow. The system gives both kinetic and quantitative equilibrated information. By tracking the interactions of aqueous additive mixtures and liquid CO2, at 80 bar and 24 °C, under flow, measurement at a given P, T condition is done in 0.25 s. The acidification rate to steady state was found to be mass transport limited, occurring in less than 1 s. For 30 mM of the additives ammonium acetate and ammonium formate, equilibrium pH of 4.5 and 4.1, respectively, was seen. These additives are of key importance in common mobile phases used in SFC.

    Keywords
    Supercritical fluid chromatography, High-pressure microfluidics, Additive salts, Dense CO, Multiphase flow, Image analysis
    National Category
    Chemical Engineering Engineering and Technology
    Identifiers
    urn:nbn:se:uu:diva-353940 (URN)10.1016/j.supflu.2018.02.012 (DOI)000430767400011 ()
    Funder
    Knut and Alice Wallenberg Foundation
    Available from: 2018-06-18 Created: 2018-06-18 Last updated: 2018-08-02Bibliographically approved
  • 2.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Ek, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hedman, Ludvig
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Johansson, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Sehlstedt, Viktor
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Stocklassa, Jesper
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Snögren, Pär
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Pettersson, Victor
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Larsson, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Vizuete, Olivier
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thin film metal sensors in fusion bonded glass chips for high-pressure microfluidics2017In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 27, no 1, article id 015018Article in journal (Refereed)
    Abstract [en]

    High-pressure microfluidics offers fast analyses of thermodynamic parameters for compressed process solvents. However, microfluidic platforms handling highly compressible supercritical CO2 are difficult to control, and on-chip sensing would offer added control of the devices. Therefore, there is a need to integrate sensors into highly pressure tolerant glass chips. In this paper, thin film Pt sensors were embedded in shallow etched trenches in a glass wafer that was bonded with another glass wafer having microfluidic channels. The devices having sensors integrated into the flow channels sustained pressures up to 220 bar, typical for the operation of supercritical CO2. No leakage from the devices could be found. Integrated temperature sensors were capable of measuring local decompression cooling effects and integrated calorimetric sensors measured flow velocities over the range 0.5-13.8 mm/s. By this, a better control of high-pressure microfluidic platforms has been achieved.

  • 3.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Fracture strength of glass chips for high-pressure microfluidics2016In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 26, no 9, article id 095009Article in journal (Refereed)
    Abstract [en]

    High-pressure microfluidics exposes new areas in chemistry. In this paper, the reliability of transparent borosilicate glass chips is investigated. Two designs of circular cavities are used for fracture strength tests, either 1.6 mm wide with rounded corners to the fluid inlets, or 2.0 mm wide with sharp inlet corners. Two kinds of tests are done, either short-term,e.g. pressurization to fracture at room temperature, or long-term, with fracture at constant pressurization for up to one week, in the temperature region 11–125 °C. The speed of crack fronts is measured using a high-speed camera. Results show fracture stresses in the range of 129 and 254 MPa for short-term measurements. Long-term measurements conclude the presences of a temperature and stress dependent delayed fracture. For a reliability ofone week at 11–38 °C, a pressure limit is found at the lower end of the short-term measurements, or 15% lower than the average. At 80 °C, this pressure limit is 45% lower. Crack speeds are measured to be 10−5 m s-1 during short-term fracture. These measurements are comparable with estimations based on slow crack growth and show that the growth affects the reliability of glass chips. This effect is strongly affected by high temperatures, thus lowers the operating window of high-pressure glass microfluidic devices.

  • 4.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High pressure glass microfluidics for supercritical CO2 with aqueous solutions2016Conference paper (Refereed)
    Abstract [en]

    A microfluidic system is presented to investigate interactions between supercritical CO2 and H2O using high-pressure glass chips. The reliability of these chips at pressures necessary to sustain CO2 in the supercritical phase is dependent of both time and temperature. 130 bar can be kept at 38°C for more than a week. These systems can be used to investigate fluid interaction between supercritical CO2 and aqueous solutions by the addition of pH sensitive dye and high speed absorption light imagining, making it possible to demonstrate acidification is in a multiphase chip. By the addition of integrated temperature sensors, better control of the states of the fluids inside the chips can be achieved.

  • 5.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High-Speed Imaging Of The ph Drop In Aqueous solutions In Contact With Supercritical Co2 Segments2016Conference paper (Other academic)
    Abstract [en]

    A high-speed imaging system based on light absorption of bromophenol blue (BPB) pH sensitivedye in a glass high-pressure microchip is used to study the instantaneous dynamics of a pH drop in anaqueous phase in contact with segments of subcritical (liquid) and supercritical CO2. The dynamics ofthe pH-drop has been studied and visualized, demonstrating acidification rates of up to 3.5 pH/s.

  • 6.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High Pressure Glass Devices For CO2 And H2O2016Conference paper (Other academic)
    Abstract [en]

    A microfluidic system is presented to investigate interactions between supercritical CO2 and H2O using high-pressure glass chips. The reliability of these chips at pressures necessary to sustain CO2 in the supercritical phase is dependent of both time and temperature. 130 bar can be kept at 38°C for more than a week. These systems can be used to create parallel flow streams used to investigate reaction dynamics by the addition of pH sensitive dyes. 

  • 7.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Svensson, karolina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Södergren, Simon
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microfluidics for High-Pressure Analyses2018In: 12th Micronano System Workshop (MSW 2018, May 14-15, 2018, Espoo, Finland) / [ed] Samilu Fransilla, 2018, p. 8-8Conference paper (Refereed)
    Abstract [en]

    When using appropriate materials and microfabrication techniques, the small dimensionsand mechanical stability of microstructured devices allow for processes at high pressureswithout loss in safety. The largest area of applications has been demonstrated in chemistry,where extraction, synthesis and analyses often excel at high densities and high temperatures.These two parameters are accessible through high pressures. Capillary chemistry has beenused since long but, just like in low-pressure applications, there are several advantages in usingmicrofluidic platforms for control of reactions, catalysis, mixing and separation. For example,planar isothermal set-ups, large local variations in geometries, dense form factors, small deadvolumes and precisely positioned microstructures.In analytical systems, we are studying high-pressure components and microsystems forsampling, sample preparation, analyses and fractionation. We will present what drives ourresearch and development: Our experimental set-up with high-pressure pumps, high-speedcamera, sensors, valves, piston-chambers, backpressure regulators, cooling table, etc. How wehave built capability in pumping and valving by the use of stainless steel and paraffinactuation. How we are making high pressure silicon-glass and glass-glass chips with integratedelectrical thin film sensors, using printed circuit boards to ease handling of the chips andintegrating modules. A set of relevant publications are listed below.

  • 8.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Knaust, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Ogden, Sam
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Bodén, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Integrated high-pressure fluid manipulation in microfluidic systems2014Conference paper (Other academic)
  • 9.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Mårtensson, Gustaf
    EMSL, MC2, Chalmers University of Technology, Göteborg, Sweden.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Flowing and pressurizing a solid-liquid two phase monodispersed fluid with high solid content in a transparent microfluidic high-pressure chip2017Conference paper (Refereed)
  • 10.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Mårtensson, Gustav
    Mycronic AB, Täby.; Chalmers Univ Technol, MC2, EMSL, Gothenburg.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Flowing and pressurizing a solid-liquid two phase monodispersed fluid with high solid content in a transparent microfluidic high-pressure chip2017In: 28TH MICROMECHANICS AND MICROSYSTEMS EUROPE WORKSHOP, IOP PUBLISHING LTD , 2017, article id UNSP 012010Conference paper (Refereed)
    Abstract [en]

    Handling highly concentrated solid-liquid two-phase fluids in microfluidics is challenging. In this paper, we present the first studies of flowing solder paste with a high solid content in a transparent high-pressure tolerant glass chip, thereby increasing the understanding of how multiphase liquids with high density difference between the phases behave in small channels (840 mu m in diameter). The system, including a custom made high-pressure, low resistance, interface, was continuously operated at pressures up to of 6 MPa and devices where shown to have pressure tolerance up to 17 MPa. During flow through the chip, the packing density of the solder balls displayed inhomogeneity over the channel where chains of solder balls in contact with each other were formed together with voids. These in-homogeneities persisted along the channel during flow. The flow rate of the paste through the chip oscillated between 63 to 350 mu m/s when pumping at constant volume rate of 30 mu l/min. When a pressure of 2 MPa was applied, the volume of the solder paste particle segment decreased 1.6%, and 0.1% was elastically recovered when the pressure was released. It is concluded that this transparent microfluidic high-pressure glass chip with the special developed interface is suitable for flow studies of solder paste with a high solid content.

  • 11.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Rodriguez-Meizoso, Irene
    Turner, Charlotta
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Dynamic pH determination at high pressure of aqueous additive mixtures in contact with dense CO22018In: Journal of Supercritical Fluids, ISSN 0896-8446, E-ISSN 1872-8162, Vol. 136, p. 95-101Article in journal (Refereed)
    Abstract [en]

    A system consisting of a high-pressure tolerant microfluidic glass chip, high-speed absorbance imaging, and image processing has been developed to study rapid dynamic events like pH change in a multiphase flow. The system gives both kinetic and quantitative equilibrated information. By tracking the interactions of aqueous additive mixtures and liquid CO2, at 80 bar and 24 °C, under flow, measurement at a given P, T condition is done in 0.25 s. The acidification rate to steady state was found to be mass transport limited, occurring in less than 1 s. For 30 mM of the additives ammonium acetate and ammonium formate, equilibrium pH of 4.5 and 4.1, respectively, was seen. These additives are of key importance in common mobile phases used in SFC.

  • 12.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Stocklassa, Jesper
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Control Systems For Gas-Expanded Liquids In Microreactors2017Conference paper (Refereed)
  • 13.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Svensson, Karolina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    A microfluidic control board for high-pressure flow, composition, and relative permittivity2018In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 90, no 21, p. 12601-12608Article in journal (Refereed)
    Abstract [en]

    Flow control is central to microfluidics and chromatography. With decreasing dimensions and high pressures, precise fluid flows are often needed. In this paper, a high-pressure flow control system is presented, allowing for the miniaturization of chromatographic systems and the increased performance of microfluidic setups by controlling flow, composition and relative permittivity of two-component flows with CO2. The system consists of four chips: two flow actuator chips, one mixing chip and one relative permittivity sensor. The actuator chips, throttling the flow, required no moving parts as they instead relied on internal heaters to change the fluid resistance. This allows for flow control using miniaturized fluid delivery systems containing only a single pump or pressure source. Mobile phase gradients between 49% to 74% methanol in CO2 were demonstrated. Depending on how the actuator chips were dimensioned, the position of this range could be set for different method-specific needs. With the microfluidic control board, both flow and composition could be controlled from constant pressure sources, drift could be removed, and variations in composition could be lowered by 84%, resulting in microflows of CO2 and methanol with a variation in the composition of 0.30%.

  • 14.
    Andersson, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Wilson, Anton
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    A microfluidic relative permittivity sensor for feedback control of carbon dioxide expanded liquid flows2019In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 285, p. 165-172Article in journal (Refereed)
    Abstract [en]

    Binary CO2-alcohol mixtures, such as CO2-expanded liquids (CXLs), are promising green solvents for reaching higher performance in flow chemistry and separation processing. However, their compressibility and high working pressure makes handling challenging. These mixtures allow for a tuneable polarity but, to do so, requires precise flow control. Here, a high-pressure tolerant microfluidic system containing a relative permittivity sensor and a mixing chip is used to actively regulate the relative permittivity of these fluids and indirectly—composition. The sensor is a fluid-filled plate capacitor created using embedded 3D-structured thin films and has a linearity of 0.9999, a sensitivity of 4.88 pF per unit of relative permittivity, and a precision within 0.6% for a sampling volume of 0.3 μL. Composition and relative permittivity of CO2-ethanol mixtures were measured at 82 bar and 21 °C during flow. By flow and dielectric models, this relationship was found to be described by the pure components and a quadratic mixing rule with an interaction parameter, kij, of -0.63 ± 0.02. Microflows with a relative permittivity of 1.7–21.4 were generated, and using the models, this was found to correspond to compositions of 6–90 mol % ethanol in CO2. With the sensor, a closed loop control system was realised and CO2-ethanol flows were tuned to setpoints of the relative permittivity in 30 s.

  • 15.
    Cedervall, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Chalmers Univ Technol, Dept Chem & Chem Engn, SE-41296 Gothenburg, Sweden.
    Delczeg-Czirjak, Erna Krisztina
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Iusan, Diana
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Pereiro, Manuel
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Roy, P.
    Radboud Univ Nijmegen, Inst Mol & Mat, Heyendaalseweg 135, NL-6525 AJ Nijmegen, Netherlands.
    Ericsson, Tore
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Häggström, Lennart
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Physics.
    Lohstroh, W.
    Tech Univ Munich, Heinz Maier Leibnitz Zentrum MLZ, Garching Bei Munchen, Lichtenbergstr, D-185748 Garching, Germany.
    Mutka, H.
    Inst Laue Langevin, BP 156, F-38042 Grenoble 9, France.
    Sahlberg, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Inorganic Chemistry.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Deen, P. P.
    European Spallat Source ESS ERIC, Box 176, SE-22100 Lund, Sweden;Univ Copenhagen, Nanosci Ctr, Niels Bohr Inst, DK-2100 Copenhagen O, Denmark.
    Magnetocaloric effect in Fe2P: Magnetic and phonon degrees of freedom2019In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 99, no 17, article id 174437Article in journal (Refereed)
    Abstract [en]

    Devices based on magnetocaloric materials provide great hope for environmentally friendly and energy efficient cooling that does not rely on the use of harmful gasses. Fe2P based compounds are alloys that have shown great potential for magnetocaloric devices. The magnetic behavior in Fe2P is characterized by a strong magnetocaloric effect that coexists with a first-order magnetic transition (FOMT). Neutron diffraction and inelastic scattering, Mossbauer spectroscopy, and first-principles calculations have been used to determine the structural and magnetic state of Fe2P around the FOMT. The results reveal that ferromagnetic moments in the ordered phase are perturbed at the FOMT such that the moments cant away from the principle direction within a small temperature region. The acoustic-phonon modes reveal a temperature-dependent nonzero energy gap in the magnetically ordered phase that falls to zero at the FOMT. The interplay between the FOMT and the phonon energy gap indicates hybridization between magnetic modes strongly affected by spin-orbit coupling and phonon modes leading to magnon-phonon quasiparticles that drive the magnetocaloric effect.

  • 16.
    Cruz, Javier
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Zadeh, S. Hooshmand
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Graells, Tiscar
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences. Univ Autonoma Barcelona, Dept Genet & Microbiol, Barcelona, Spain..
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Malmström, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Wu, Zhigang G.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan, Peoples R China..
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High pressure inertial focusing for separating and concentrating bacteria at high throughput2017In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 27, no 8, article id 084001Article in journal (Refereed)
    Abstract [en]

    Inertial focusing is a promising microfluidic technology for concentration and separation of particles by size. However, there is a strong correlation of increased pressure with decreased particle size. Theory and experimental results for larger particles were used to scale down the phenomenon and find the conditions that focus 1 mu m particles. High pressure experiments in robust glass chips were used to demonstrate the alignment. We show how the technique works for 1 mu m spherical polystyrene particles and for Escherichia coli, not being harmful for the bacteria at 50 mu l min(-1). The potential to focus bacteria, simplicity of use and high throughput make this technology interesting for healthcare applications, where concentration and purification of a sample may be required as an initial step.

  • 17.
    Fu, Le
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Unosson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Engqvist, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Xia, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Influence of alkali metal additives on phase transition of translucent ZrO2/SiO2 glass ceramics prepared by a sol-gel method2015In: European Cells and Materials, ISSN 1473-2262, E-ISSN 1473-2262, Vol. 29Article in journal (Refereed)
  • 18.
    Knaust, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Influence of surface modifications and channel structure for microflows of supercritical carbon dioxide and water2016In: Journal of Supercritical Fluids, ISSN 0896-8446, E-ISSN 1872-8162, Vol. 107, p. 649-656Article in journal (Refereed)
    Abstract [en]

    Miniaturization offers a possibility to increase the performance and decrease the time scales of systems. Existing microsystems using supercritical CO2 mainly utilizes multiphase segmented flows. To allow for a broader toolbox for future systems, also parallel flows are useful which eases the separation of the different phases. Here, the effect of different surface coatings are studied for multiphase flows of scCO2 and H2O in flat microchannels, with and without a 4 μm high ridge guide, which allows for pinning of the fluid interface inside the 190 μm wide and 35 μm high channel. Three different surfaces with different wettings towards scCO2 and H2O are studied, where a surface terminated with a hydrocarbon-based silane was observed to be neutral in the H2O/scCO2 system, a surface terminated with a fluorocarbon-based silane was hydrophobic, and an uncoated glass surface was hydrophilic.

    Using two flow rates of 5:5 μl/min (CO2:H2O) and 6.5:3.5 μl/min (CO2:H2O), a parallel flow between scCO2 and H2O was observed for uncoated and flat channels where the H2O flow pushed the CO2 to the side, before the flows eventually breaks up into segments. With a ridge guide in the middle of the channel, the interface was pinned at half the channel width, although still breaking up into segments. The neutral hydrocarbon-based surface coating with approximately 90° contact angles resulted in evenly created segments without a ridge guide. Including a guide in the middle of the channel, a parallel flow was observed throughout the channel, although occasionally small CO2 segments entered the H2O outlet. Using the fluorocarbon-based silane resulted in an unstable segmented system with pressure fluctuations.

    Using surface modifications, an increased control can be achieved for either segmentation or parallel flow where a neutral surface is favored for a stable flow behavior. Together with a ridge guide, the fluid interface was pinned at the center. 

  • 19.
    Knaust, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Mannitol for High Temperature Phase Change Actuators2014Conference paper (Other academic)
    Abstract [en]

    To enable valves for hot water microsystems, the possibility of using the volume expansion of the phase transition from solid to liquid in mannitol for strong high temperature actuators was studied. From room temperature to 160°C, a linear expansion of 4% was measured, and the expansion at the phase transition from solid to liquid at 160°C to 180°C was measured to be 7%. Stainless steel structures with a stainless steel diaphragm was filled and repeatedly heated up to 180◦C while measuring the deflection of the diaphragm using a laser sensor. The height differences was measured to be 25 μm at 180°C.

    In combination with a fluidic system, the mannitol actuator should capable as a valve for hot water microsystems. 

  • 20.
    Knaust, Stefan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Rogeman, Niklas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Amberg, Gustav
    KTH.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Influence of flow rate, temperature and pressure on multiphase flows of supercritical carbon dioxide and water using multivariate partial least square regression2015In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 10, article id 105001Article in journal (Refereed)
    Abstract [en]

    Supercritical carbon dioxide (scCO2) is often used to replace harmful solvents and can dissolve a wide range of organic compounds. With a favorable critical point at 31 °C and 7.4 MPa, reaching above the critical point for scCO2 is fairly accessible. Because of the compressible nature of scCO2 and the large changes of viscosity and density with temperature and pressure, there is a need to determine the behavior of scCO2 in microfluidic systems. Here, the influence of how parameters such as flow rate, temperature, pressure, and flow ratio affects the length of parallel flow of water and scCO2 and the length of the created CO2 segments are investigated and modeled using multivariate data analysis for a 10 mm long double-y channel. The parallel length and segment size were observed in the laminar regime around and above the critical point of CO2. The flow ratio between the two fluids together with the flow rate influenced both the parallel length and the segment sizes, and a higher pressure resulted in shorter parallel lengths. Regarding the segment length of CO2, longer segments were a result of a higher Weber number for H2O together with a higher temperature in the channel. 

  • 21.
    Ohlin, Mathias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    In situ temperature monitoring during acoustophoresis using integrated thin film Pt temperature sensors2017Conference paper (Refereed)
  • 22.
    Ohlin, Mathias
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Internal temperature sensing in an acoustophoretic glass chip2017Conference paper (Refereed)
  • 23.
    Svensson, Karolina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Södergren, Simon
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    High-pressure microfluidic electrochemical and image analysis dual detection for HPLC2018Conference paper (Other academic)
    Abstract [en]

    High-performance liquid chromatography (HPLC) is often set as the lab-based golden standard. For point-of-care and point-of-site applications, making HPLC portable, easy to use and low cost, is very desirable. To reach lower costs, one important task is the development of suitable detectors. Because of the potential for low cost and high performance, a dual-detection microfluidic chip with an electrochemical detector (ECD) and optical access for image analysis was evaluated at high pressure, downstream an HPLC column. For the image analysis, a camera and near-UV-light was used to extract absorption data. To validate the response, a spectrometer was coupled downstream the chip. The results of the three different detectors were comparable, with the camera providing similar absorbance-time chromatograms as the spectrometer. However, the ECD registered only peaks from one of two analytes. To conclude, this experimental setup has potential to provide better understanding of the capability for microfluidic HPLC systems.

  • 24.
    Werr, Gabriel
    et al.
    Tech Univ Munich, Inst Med & Polymer Engn, D-80333 Munich, Germany.
    Khaji, Zahra
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Ohlin, Mathias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab. Aimpoint AB, S-21375 Malmo, Sweden.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Searle, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab. Natl Univ Singapore, Dept Biomed Engn, Singapore 117583, Singapore.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Integrated thin film resistive sensors for in situ temperature measurements in an acoustic trap2019In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 29, no 9, article id 095003Article in journal (Refereed)
    Abstract [en]

    This work presents an acoustic trap with integrated thin film sensors to monitor temperature variations during operation. The acoustic trap is wet-etched in glass with a thermally bonded glass lid and the thin-film sensors are integrated during fabrication. We evaluated the performance of the integrated temperature sensors and measured a temperature sensitivity of +/- 0.01 degrees C and confirmed that the read-out of the thin film sensors was not affected neither by the ionic conductivity of the solution nor the addition of microparticles into the acoustic trap. From the experiments we observed a temperature increase of the acoustic trap during operation as a result of the dissipative heating of the the piezoelectric element used to actuate the trap. We also showed that when external convective cooling was applied to the system, the temperature increase of the acoustic trap was higher than the temperature increase of the piezoelectric element itself. This shows the importance of using integrated temperature sensors in acoustic trapping to monitor the local environmental conditions.

  • 25.
    Werr, Gabriel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Khaji, Zahra
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Ohlin, Mathias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Andersson, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    Klintberg, Lena
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Searle, Sean
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab. Department of Biomedical Engineering, National University of Singapore, Singapore 117583, Singapore.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology, Ångström Space Technology Centre (ÅSTC). Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Tenje, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Integrated thin film resistive sensors for in situ temperature measurements in an acoustic trap2019In: Acoustofluidics 2019: This annual meeting will be held in Twente, The Netherlands in 2019. This focused meeting is dedicated to exploring the science, engineering, and use of micro- to nanoscale acoustofluidics., 2019, p. 140-141Conference paper (Other academic)
    Abstract [en]

    This work presents an acoustic trap with integrated thin film sensors to monitor temperature variations during operation. The acoustic trap is wet-etched in glass with a thermally bonded glass lid and the thin-film sensors are integrated during fabrication. We evaluated the performance of the integrated temperature sensors and measured a temperature sensitivity of ±0.01 °C and confirmed that the read-out of the thin film sensors was not affected neither by the ionic conducitiviy of the solution nor the addition of microparticles into the acoustic trap. From the experiments we observed a temperature increase of the acoustic trap during operation as a result of the dissipative heating of the the piezoelectric element used to actuate the trap. We also showed that when external convective cooling was applied to the system, the temperature increase of the acoustic trap was higher than the temperature incresase of the piezoelectric element itself. This shows the importance of using integrated temperature sensors in acoustic trapping to monitor the environmental conditions.

1 - 25 of 25
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