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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 pHsensors concepts have been proposed, however, there is still a need for improved sensor solutionswith respect to reliability, durability and miniaturization but also for multiparameter sensing. Here wepresent a conceptual verification, which includes theoretical simulations as well as experimentalevaluation of a fiber optic pH-sensor based on a bio-compatible pH sensitive material not previouslyused 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 splicedbetween two standard single mode fibers. The working principle of the sensor is simulated by usingCOMSOL Multiphysics. The simulations are used as a guideline for the construction of the sensorsthat 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 developedsensor concept can find future use in many medical- or bio-chemical applications as well as inenvironmental monitoring of large areas. Challenges encountered during the sensor developmentdue to variation in the design parameters are discussed.

Keywords
interferometric, Mach-Zehnder, pH, sensor, hydrogel, simulation
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:miun:diva-35646 (URN)10.3390/photonics6010011 (DOI)000464341200003 ()2-s2.0-85063143389 (Scopus ID)
Note

MDPI Photonics Special Issue "Advanced Optical Materials and Devices"

Available from: 2019-02-14 Created: 2019-02-14 Last updated: 2020-01-17Bibliographically 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, p. 15article 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.

Place, publisher, year, edition, pages
Basel, Switzerland: MDPI, 2018. p. 15
Keywords
interdigital, hydrogel, penetration depth, pH, sensor, coating, thin film, laser ablation, oligo (β-amino esters)
National Category
Natural Sciences
Identifiers
urn:nbn:se:miun:diva-34203 (URN)10.3390/chemosensors6030030 (DOI)000448395400006 ()2-s2.0-85052627188 (Scopus ID)
Available from: 2018-07-25 Created: 2018-07-25 Last updated: 2020-01-17Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-0631-3804

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