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Publications (10 of 21) Show all publications
Engholm, M., Hammarling, K., Andersson, H., Sandberg, M. & Nilsson, H. E. (2019). A bio-compatible fiber optic pH sensor based on a thin core interferometric technique. Photonics, 6(1), Article ID 11.
Open this publication in new window or tab >>A bio-compatible fiber optic pH sensor based on a thin core interferometric technique
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2019 (English)In: Photonics, ISSN 2304-6732, Vol. 6, no 1, article id 11Article in journal (Refereed) Published
Abstract [en]

There is an increasing demand for compact, reliable and versatile sensor concepts for pH-level monitoring within several industrial, chemical as well as bio-medical applications. Many pH sensors concepts have been proposed, however, there is still a need for improved sensor solutions with respect to reliability, durability and miniaturization but also for multiparameter sensing. Here we present a conceptual verification, which includes theoretical simulations as well as experimental evaluation of a fiber optic pH-sensor based on a bio-compatible pH sensitive material not previously used in this context. The fiber optic sensor is based on a Mach-Zehnder interferometric technique, where the pH sensitive material is coated on a short, typically 20-25 mm thin core fiber spliced between two standard single mode fibers. The working principle of the sensor is simulated by using COMSOL Multiphysics. The simulations are used as a guideline for the construction of the sensors that have been experimentally evaluated in different liquids with pH ranging from 1.95 to 11.89. The results are promising, showing the potential for the development of bio-compatible fiber optic pH sensor with short response time, high sensitivity and broad measurement range. The developed sensor concept can find future use in many medical- or bio-chemical applications as well as in environmental monitoring of large areas. Challenges encountered during the sensor development due to variation in the design parameters are discussed. © 2019 by the authors.

Keywords
Hydrogel, Interferometric, Mach-Zehnder, PH, Sensor, Simulation
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-38262 (URN)10.3390/photonics6010011 (DOI)2-s2.0-85063143389 (Scopus ID)
Note

Funding details: Japan Society for the Promotion of Science, JSPS, JP17H01269; Funding details: Japan Society for the Promotion of Science, JSPS, JP18H01499; Funding text 1: This work was partially supported by JSPS KAKENHI, Grant Numbers JP18H01499 and JP17H01269

Available from: 2019-04-02 Created: 2019-04-02 Last updated: 2019-06-20Bibliographically approved
Granberg, H., Sandberg, M. & Håkansson, K. (2019). Pilot scale production of interactive zinc oxide paper and its multiple applicability. In: PaperCon 2019: Proceedings. Paper presented at PaperCon 2019. Proceedings of a conference held in Indianapolis, Indiana, USA, 5-8 May 2019. TAPPI Press, Article ID PF3.3.
Open this publication in new window or tab >>Pilot scale production of interactive zinc oxide paper and its multiple applicability
2019 (English)In: PaperCon 2019: Proceedings, TAPPI Press, 2019, article id PF3.3Conference paper, Published paper (Other academic)
Abstract [en]

A study has been made of the production of zinc oxide (ZnO) paper in a pilot paper machine. Bleached sulphate softwood pulp (70%) and bleached sulphate hardwood pulp (30%) were corefined. Cationic polyacrylamide (CPAM) was used as retention agent, while alkyl ketene dimer (AKD) was used as sizing agent for some samples. Some papers were screen printed with a conducting carbon-based ink to produce a photosensor device. Two methods were used to study the photocatalysis: immersing ZnO papers into kongo red dispersions or resazurin (Rz) based photocatalyst activity indicator ink and exposing the papers to ultraviolet (UV) light in a sunlight simulator. ZnO papers of approximately 60gsm were successfully produced on the pilot scale machine, which was run at a low speed (100m/min) and the retention of ZnO particles was good in all samples. The paper looked like an ordinary white printing paper product, but was a truly interactive material, exhibiting photoconductivity and enabling use as an excellent photosensor.

Place, publisher, year, edition, pages
TAPPI Press, 2019
Keywords
speciality paper, zinc oxide, pilot trial, paper properties, photoconductivity, photoconductor
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-40586 (URN)
Conference
PaperCon 2019. Proceedings of a conference held in Indianapolis, Indiana, USA, 5-8 May 2019
Available from: 2019-10-28 Created: 2019-10-28 Last updated: 2019-10-31Bibliographically approved
Hammarling, K., Engholm, M., Andersson, H., Sandberg, M. & Nilsson, H. E. (2018). Broad-range hydrogel-based pH sensor with capacitive readout manufactured on a flexible substrate. Chemosensors, 6(3), Article ID 30.
Open this publication in new window or tab >>Broad-range hydrogel-based pH sensor with capacitive readout manufactured on a flexible substrate
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2018 (English)In: Chemosensors, ISSN 2227-9040, Vol. 6, no 3, article id 30Article in journal (Refereed) Published
Abstract [en]

Environmental monitoring of land, water and air, is an area receiving greater attention because of human health and safety concerns. Monitoring the type of pollution and concentration levels is vital, so that appropriate contingency plans can be determined. To effectively monitor the environment, there is a need for new sensors and sensor systems that suits these type of measurements. However, the diversity of sensors suitable for low, battery powered- and large area sensor systems are limited. We have manufactured and characterized a flexible pH sensor using laser processing and blade coating techniques that is able to measure pH between 2.94 and 11.80. The sensor consists of an interdigital capacitance with a pH sensitive hydrogel coating. Thin sensors can reach 95% of their final value value within 3 min, and are stable after 4 min. Good repeatability was achieved in regard to cycling of the sensor with different pH and multiple measurements from dry state. We have also studied the relation between an interdigital capacitance penetration depth and hydrogels expansion. We believe that our passive sensor is suitable to be used in low power and large area sensor networks.

Keywords
Coating, Hydrogel, Interdigital, Laser ablation, Oligo (b-amino esters), Penetration depth, PH, Sensor, Thin film
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-35154 (URN)10.3390/chemosensors6030030 (DOI)2-s2.0-85052627188 (Scopus ID)
Available from: 2018-09-11 Created: 2018-09-11 Last updated: 2019-06-20Bibliographically approved
Sani, N., Linderhed, U. & Sandberg, M. (2018). Monolithically integrated electrochemical energy storage modules. Journal of Energy Storage, 16, 139-144
Open this publication in new window or tab >>Monolithically integrated electrochemical energy storage modules
2018 (English)In: Journal of Energy Storage, ISSN 2352-152X, Vol. 16, p. 139-144Article in journal (Refereed) Published
Abstract [en]

The concept of monolithic integration of electrochemical energy storage modules was tested on serially connected supercapacitor cells balanced by passive resistive dissipation. Five electrode pairs with collectors, interconnects, corrosion protection layers, electrode material and shunt resistors were printed on a single substrate. The printed patterns, lamination film, and a hot-sealing tool were designed so that upon folding, lamination, and electrolyte filling and sealing, five serial cells were formed with each having a shunt resistance. In an open circuit idling period following charge and discharge, the standard deviation of the individual cell voltages decreased, demonstrating the balancing function of this so called “modulit”, a short term proposed for a monolithically integrated electrochemical energy storage module.

Keywords
Balancing, Monolithic integration, Printed serial modules, Resistive dissipation, Supercapacitors
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33427 (URN)10.1016/j.est.2018.01.004 (DOI)2-s2.0-85041378473 (Scopus ID)
Available from: 2018-03-09 Created: 2018-03-09 Last updated: 2019-06-27Bibliographically approved
Hammarling, K., Sandberg, M., Engholm, M., Andersson, H. & Nilsson, H.-E. (2018). Synthesis, Curing Behavior and Swell Tests of pH-Responsive Coatings from Acryl-Terminated Oligo(beta-Amino Esters). Chemosensors, 6(1), Article ID 10.
Open this publication in new window or tab >>Synthesis, Curing Behavior and Swell Tests of pH-Responsive Coatings from Acryl-Terminated Oligo(beta-Amino Esters)
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2018 (English)In: Chemosensors, ISSN 2227-9040, Vol. 6, no 1, article id 10Article in journal (Refereed) Published
Abstract [en]

The ability of acryl-terminated oligo(beta-amino esters) (AOBAE) to be coated on fibers and printed electronics without solvents and to be cross-linked to a pH-responsive coatings, makes AOBAE-based coatings a potential type of pH-sensor coating. However, there are currently no reports of AOBAEs used as a pH-responsive coating material in sensor applications. Here we present an investigation of the synthesis, curing behavior and swell tests of AOBAEs. AOBAEs were synthesized from reacting an excess of asymmetric diacrylates with piperazine without the use of any solvents. They were then cross-linked to an insoluble network by UV-curing. Nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the AOBAEs. NMR was used to clarify the irregular structure of the AOBAE. FTIR was used to monitor the effects of UV-curing dose and air exposure on monomer conversion during curing. An interferometric technique was used to monitor the swelling behavior of the coating in response to pH variations. Swell experiments showed that the AOBAE also responded to pH variations after polymerization. Therefore, AOBAE is an interesting class of material with potential use as a pH responsive coating in optical-and printed electronics pH-sensors applications.

Place, publisher, year, edition, pages
MDPI, 2018
Keywords
oligo(beta-amino esters); acryl-terminated; 1, 3-butanediol diacrylate; piperazine; pH; sensor; coating; thin film
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-33641 (URN)10.3390/chemosensors6010010 (DOI)2-s2.0-85045393278 (Scopus ID)
Available from: 2018-04-14 Created: 2018-04-14 Last updated: 2019-06-20Bibliographically approved
Keshmiri, V., Westerberg, D., Andersson Ersman, P., Sandberg, M., Forchheimer, R. & Tu, D. (2017). A Silicon-Organic Hybrid Voltage Equalizer for Supercapacitor Balancing. IEEE Journal on Emerging and Selected Topics in Circuits and Systems, 7(1), 114-122, Article ID 7817802.
Open this publication in new window or tab >>A Silicon-Organic Hybrid Voltage Equalizer for Supercapacitor Balancing
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2017 (English)In: IEEE Journal on Emerging and Selected Topics in Circuits and Systems, ISSN 2156-3357, Vol. 7, no 1, p. 114-122, article id 7817802Article in journal (Refereed) Published
Abstract [en]

Cell voltage equalizers are an important part in electric energy storage systems comprising series-connected cells, for example, supercapacitors. Hybrid electronics with silicon chips and printed devices enables electronic systems with moderate performance and low cost. This paper presents a silicon-organic hybrid voltage equalizer to balance and protect series-connected supercapacitor cells during charging. Printed organic electrochemical transistors with conducting polymer poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) are utilized to bypass excess current when the supercapacitor cells are fully charged to desired voltages. In this study, low-cost silicon microcontrollers (ATtiny85) are programmed to sense voltages across the supercapacitor cells and control the organic electrochemical transistors to bypass charging current when the voltages exceed 1 V. Experimental results show that the hybrid equalizer with the organic electrochemical transistors works in dual-mode, switched-transistor mode or constant-resistor mode, depending on the charging current applied (0.3-100 mA). With the voltage equalizer, capacitors are charged equally regardless of their capacitances. This work demonstrates a low-cost hybrid solution for supercapacitor balancing modules at large-scale packs.

Keywords
Hybrid electronics, organic electrochemical transistors, printed electronics, supercapacitor balancing, voltage equalizer, Conducting polymers, Conductive plastics, Equalizers, Silicon, Styrene, Transistors, Charging current, Electric energies, Electronic systems, Hybrid solution, Poly(styrene sulfonate), Poly-3, 4-ethylenedioxythiophene, Series-connected, Capacitance
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:ri:diva-31012 (URN)10.1109/JETCAS.2016.2612724 (DOI)2-s2.0-85009877621 (Scopus ID)
Available from: 2017-09-04 Created: 2017-09-04 Last updated: 2019-06-20Bibliographically approved
Brooke, R., Mitraka, E., Sardar, S., Sandberg, M., Sawatdee, A., Berggren, M., . . . Jonsson, M. P. (2017). Infrared electrochromic conducting polymer devices. Journal of Materials Chemistry C, 5(23), 5824-5830
Open this publication in new window or tab >>Infrared electrochromic conducting polymer devices
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2017 (English)In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 5, no 23, p. 5824-5830Article in journal (Refereed) Published
Abstract [en]

The conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is well known for its electrochromic properties in the visible region. Less focus has been devoted to the infrared (IR) wavelength range, although tunable IR properties could enable a wide range of novel applications. As an example, modern day vehicles have thermal cameras to identify pedestrians and animals in total darkness, but road and speed signs cannot be easily visualized by these imaging systems. IR electrochromism could enable a new generation of dynamic road signs that are compatible with thermal imaging, while simultaneously providing contrast also in the visible region. Here, we present the first metal-free flexible IR electrochromic devices, based on PEDOT:Tosylate as both the electrochromic material and electrodes. Lateral electrochromic devices enabled a detailed investigation of the IR electrochromism of thin PEDOT:Tosylate films, revealing large changes in their thermal signature, with effective temperature changes up to 10 °C between the oxidized (1.5 V) and reduced (-1.5 V) states of the polymer. Larger scale (7 × 7 cm) vertical electrochromic devices demonstrate practical suitability and showed effective temperature changes of approximately 7 °C, with good optical memory and fast switching (1.9 s from the oxidized state to the reduced state and 3.3 s for the reversed switching). The results are highly encouraging for using PEDOT:Tosylate for IR electrochromic applications.

Keywords
Conducting polymers, Electrochromic devices, Infrared imaging, Polymer films, Roads and streets, Sulfur compounds, Temperature, Effective temperature, Electro-chromic applications, Electrochromic materials, Electrochromic properties, Infrared wavelengths, Novel applications, Poly(3, 4 ethylenedioxythiophene) (PEDOT), Thermal signatures, Electrochromism
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-31115 (URN)10.1039/c7tc00257b (DOI)2-s2.0-85021669689 (Scopus ID)
Available from: 2017-08-28 Created: 2017-08-28 Last updated: 2019-06-20Bibliographically approved
Andersson Ersman, P., Westerberg, D., Tu, D., Nilsson, M., Åhlin, J., Eveborn, A., . . . Gustafsson, G. (2017). Screen printed digital circuits based on vertical organicelectrochemical transistors. Flex. Print. Electron., 2, Article ID 045008.
Open this publication in new window or tab >>Screen printed digital circuits based on vertical organicelectrochemical transistors
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2017 (English)In: Flex. Print. Electron., Vol. 2, article id 045008Article in journal (Refereed) Published
Abstract [en]

Vertical organic electrochemical transistors (OECTs) have been manufactured solely using screenprinting. The OECTs are based on PEDOT:PSS (poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonic acid)), which defines the active material for both the transistor channel and the gateelectrode. The resulting vertical OECT devices and circuits exhibit low-voltage operation, relativelyfast switching, small footprint and high manufacturing yield; the last three parameters are explainedby the reliance of the transistor configuration on a robust structure in which the electrolyte verticallybridges the bottom channel and the top gate electrode. Two different architectures of the verticalOECT have been manufactured, characterized and evaluated in parallel throughout this report. Inaddition to the experimental work, SPICE models enabling simulations of standalone OECTs andOECT-based circuits have been developed. Our findings may pave the way for fully integrated, lowvoltageoperating and printed signal processing systems integrated with e.g. printed batteries, solarcells, sensors and communication interfaces. Such technology can then serve a low-cost basetechnology for the internet of things, smart packaging and home diagnostics applications.

Keywords
electrochemical transistor, printed electronic circuit, PEDOT:PSS, electrolyte, SPICE model, hybrid electronics
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:ri:diva-33096 (URN)10.1088/2058-8585/aa903a (DOI)2-s2.0-85040970207 (Scopus ID)
Available from: 2018-01-16 Created: 2018-01-16 Last updated: 2019-06-20Bibliographically approved
Nour, E. S., Bondarevs, A., Huss, P., Sandberg, M., Gong, S., Willander, M. & Nur, O. (2016). Low-Frequency Self-Powered Footstep Sensor Based on ZnO Nanowires on Paper Substrate. Nanoscale Research Letters, 11(1), Article ID 156.
Open this publication in new window or tab >>Low-Frequency Self-Powered Footstep Sensor Based on ZnO Nanowires on Paper Substrate
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2016 (English)In: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 11, no 1, article id 156Article in journal (Refereed) Published
Abstract [en]

In this work, we design and fabricate a wireless system with the main operating device based on zinc oxide (ZnO) nanowires. The main operating device is based on piezoelectric nanogenerator (NG) achieved using ZnO nanowires grown hydrothermally on paper substrate. The fabricated NG is capable of harvesting ambient mechanical energy from various kinds of human motion, e.g., footsteps. The harvested electric output has been used to serve as a self-powered pressure sensor. Without any storage device, the signal from a single footstep has successfully triggered a wireless sensor node circuit. This study demonstrates the feasibility of using ZnO nanowire piezoelectric NG as a low-frequency self-powered sensor, with potential applications in wireless sensor networks.

Keywords
Energy harvesting, Hydrothermal growth, Nanogenerator, Piezoelectric nanowire, Wireless data transmission, ZnO, Digital storage, Nanotechnology, Nanowires, Piezoelectricity, Sensor nodes, Virtual storage, Zinc oxide, Mechanical energies, Operating devices, Piezoelectric nanogenerator, Wireless sensor node, Zinc oxide (ZnO), Wireless sensor networks
National Category
Computer and Information Sciences
Identifiers
urn:nbn:se:ri:diva-27692 (URN)10.1186/s11671-016-1373-1 (DOI)2-s2.0-84961588464 (Scopus ID)
Available from: 2017-10-12 Created: 2016-12-22 Last updated: 2019-06-20Bibliographically approved
Erlandsson, J., Lopez Duran, V., Granberg, H., Sandberg, M., Larsson, P. A. & Wågberg, L. (2016). Macro- and mesoporous nanocellulose beads for use in energy storage devices. Applied Materials Today, 5, 246-254
Open this publication in new window or tab >>Macro- and mesoporous nanocellulose beads for use in energy storage devices
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2016 (English)In: Applied Materials Today, ISSN 2352-9407, Vol. 5, p. 246-254Article in journal (Refereed) Published
Abstract [en]

Chemically cross-linked, wet-stable cellulose nanofibril (CNF) aerogel beads were fabricated using a novel procedure. The procedure facilitated controlled production of millimetre-sized CNF aerogel beads without freeze-drying or critical point drying, while still retaining a highly porous structure with low density. The aerogel beads were mechanically robust in the dry state, supporting loads of 1.3 N at 70% compression, even after being soaked in water and re-dried. Furthermore, they displayed both a good stability in water and a remarkably good shape recovery after wet compression. Owing to the stability in water, the entire surface of the highly porous aerogel beads could be successfully functionalized with polyelectrolytes and carboxyl-functionalized single-wall carbon nanotubes (CF-SWCNTs) using the Layer-by-Layer technique, introducing a significant electrical conductivity (1.6 mS/cm) to the aerogel beads. The functionalized, electrically conducting aerogel beads could carry as much as 2 kA/cm2 and act as electrodes in a supercapacitor displaying a stabilized charge storage capacity of 9.8 F/g after 50 charging–discharging cycles.

Keywords
Cellulose nanofibrils, Layer-by-Layer, Size-reduced aerogel, Supercapacitor
National Category
Nano Technology
Identifiers
urn:nbn:se:ri:diva-27567 (URN)10.1016/j.apmt.2016.09.008 (DOI)2-s2.0-84995564002 (Scopus ID)
Available from: 2016-12-15 Created: 2016-12-15 Last updated: 2019-06-20Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-0631-3804

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