Piezoresistive carbon foams in sensing applications
|Author:||Kordas, Krisztian1; Pitkänen, Olli1|
1Microelectronics Research Unit, University of Oulu, Oulu, Finland
|Online Access:||PDF Full Text (PDF, 5.9 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe2019101032192
|Publish Date:|| 2019-10-10
Mechanical strain sensing is ubiquitous, found in applications such as heart rate monitoring, analysis of body part motion, vibration of machines, dilatation in buildings and large infrastructure, and so forth. Piezoresistive materials and sensors based on those offer versatile and robust solutions to measure strains and displacements and can be implemented even in acceleration and pressure analyses. In this paper, we overview the most prominent piezoresistive materials, and present a case study on carbon foams as well as on their hierarchical hybrid structures with carbon nanotubes/nanofibers. Our results show highly non-linear electrical resistance and mechanical stress dependence on uniaxial strain in both types of materials up to 50% compression. The Young’s moduli increase with compressive strain between 1–65 and 0.1–92 kPa for the foam and hierarchical structure, respectively. The foams have giant gauge factors (up to −1000) with large differential gauge factors (on the scale of −10) and differential pressure sensitivity of 0.016 Pa⁻¹ (at 10% strain) making them suitable for detecting both small and large displacements with excellent accuracy of electrical readout as we demonstrate in detecting building wall displacement as well as in monitoring heart rate and flexing of fingers.
Frontiers in materials
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
216 Materials engineering
The authors acknowledge funding received from the EU H2020 (NewPack), Business Finland (Grelectronics), Academy of Finland (Suplacat), Interreg Nord–Lapin liitto (Flexibla Transparenta Ledande Filmer som Electroder), University of Oulu (more-than-Moore RC and Entity), and Infotech Oulu.
© 2019 Kordas and Pitkänen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.