Details
| Original language | English |
|---|---|
| Article number | 113954 |
| Journal | Sensors and Actuators A: Physical |
| Volume | 347 |
| Early online date | 21 Oct 2022 |
| Publication status | Published - 1 Nov 2022 |
Abstract
Smart hydrogels are stimuli-responsive polymers which exhibit a volume-phase transition in response to external influences. This makes them promising candidates for sensing elements, especially in a biomedical context due to their easily achievable biocompatibility. The main challenge in harnessing the smart polymer's potential for sensor applications lies in a reliable transduction of the swelling change into an electrical signal. A novel platform approach is based on a bending sensor where the smart hydrogel acts as an actuator on a thin film with embedded metal traces. Mechanical deformation due to the hydrogel volume change alters the traces’ electric impedance. However, besides deformation, the medium surrounding the sensor structure will also affect the impedance. For sensor design it is therefore crucial to understand the complex interdependencies between electric sensor properties, influences of the surrounding medium and mechanical deformation. Here, an electric circuit model is presented which considers all these contributions through a minimum number of lumped elements and is strictly based on physical considerations. By employing measured impedance spectra from an experimental sensor implementation subjected to different surrounding media and mechanical deformation, the validity of the simplified model is demonstrated. A detailed analysis and discussion give insights into the determination of the different model parameters and how external influences can clearly be attributed to specific circuit elements. This work provides a general approach for deducing minimalistic but strictly physics-based circuit models which can still adequately replicate the actual behavior of such types of impedance-based bending sensors.
Keywords
- Bending sensor, Circuit model, Impedance spectrum, Smart hydrogel
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Physics and Astronomy(all)
- Instrumentation
- Physics and Astronomy(all)
- Condensed Matter Physics
- Materials Science(all)
- Surfaces, Coatings and Films
- Materials Science(all)
- Metals and Alloys
- Engineering(all)
- Electrical and Electronic Engineering
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In: Sensors and Actuators A: Physical, Vol. 347, 113954, 01.11.2022.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Physics-based circuit modeling of the impedance characteristics of a smart hydrogel-actuated bending sensor
AU - Ahmed, Benozir
AU - Reiche, Christopher F.
AU - Solzbacher, Florian
AU - Magda, Jules
AU - Körner, Julia
N1 - Funding Information: This work was performed in part at the Utah Nanofab, which is sponsored by the College of Engineering, Office of the Vice President for Research , and the Utah Science Technology and Research (USTAR) initiative of the State of Utah. The authors appreciate the support of the staff and facilities that made this work possible. Research reported in this publication was supported by the Joe W. and Dorothy Dorsett Brown Foundation , the Olive Tupper Foundation as well as the National Institute of General Medical Sciences (NIGMS) of the National Institutes of Health (NIH) under award number 1R41GM130241 awarded to Sentiomed, Inc. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.
PY - 2022/11/1
Y1 - 2022/11/1
N2 - Smart hydrogels are stimuli-responsive polymers which exhibit a volume-phase transition in response to external influences. This makes them promising candidates for sensing elements, especially in a biomedical context due to their easily achievable biocompatibility. The main challenge in harnessing the smart polymer's potential for sensor applications lies in a reliable transduction of the swelling change into an electrical signal. A novel platform approach is based on a bending sensor where the smart hydrogel acts as an actuator on a thin film with embedded metal traces. Mechanical deformation due to the hydrogel volume change alters the traces’ electric impedance. However, besides deformation, the medium surrounding the sensor structure will also affect the impedance. For sensor design it is therefore crucial to understand the complex interdependencies between electric sensor properties, influences of the surrounding medium and mechanical deformation. Here, an electric circuit model is presented which considers all these contributions through a minimum number of lumped elements and is strictly based on physical considerations. By employing measured impedance spectra from an experimental sensor implementation subjected to different surrounding media and mechanical deformation, the validity of the simplified model is demonstrated. A detailed analysis and discussion give insights into the determination of the different model parameters and how external influences can clearly be attributed to specific circuit elements. This work provides a general approach for deducing minimalistic but strictly physics-based circuit models which can still adequately replicate the actual behavior of such types of impedance-based bending sensors.
AB - Smart hydrogels are stimuli-responsive polymers which exhibit a volume-phase transition in response to external influences. This makes them promising candidates for sensing elements, especially in a biomedical context due to their easily achievable biocompatibility. The main challenge in harnessing the smart polymer's potential for sensor applications lies in a reliable transduction of the swelling change into an electrical signal. A novel platform approach is based on a bending sensor where the smart hydrogel acts as an actuator on a thin film with embedded metal traces. Mechanical deformation due to the hydrogel volume change alters the traces’ electric impedance. However, besides deformation, the medium surrounding the sensor structure will also affect the impedance. For sensor design it is therefore crucial to understand the complex interdependencies between electric sensor properties, influences of the surrounding medium and mechanical deformation. Here, an electric circuit model is presented which considers all these contributions through a minimum number of lumped elements and is strictly based on physical considerations. By employing measured impedance spectra from an experimental sensor implementation subjected to different surrounding media and mechanical deformation, the validity of the simplified model is demonstrated. A detailed analysis and discussion give insights into the determination of the different model parameters and how external influences can clearly be attributed to specific circuit elements. This work provides a general approach for deducing minimalistic but strictly physics-based circuit models which can still adequately replicate the actual behavior of such types of impedance-based bending sensors.
KW - Bending sensor
KW - Circuit model
KW - Impedance spectrum
KW - Smart hydrogel
UR - http://www.scopus.com/inward/record.url?scp=85141533982&partnerID=8YFLogxK
U2 - 10.1016/j.sna.2022.113954
DO - 10.1016/j.sna.2022.113954
M3 - Article
AN - SCOPUS:85141533982
VL - 347
JO - Sensors and Actuators A: Physical
JF - Sensors and Actuators A: Physical
SN - 0924-4247
M1 - 113954
ER -