Abstract :

Flexible and stretchable strain sensors have emerged as promising components for integration into smart wearable devices and skin-mounted applications. These sensors enable accurate detection of physiological signals, thereby finding unique applications in diverse fields such as human health monitoring, soft robotics, human-machine interface, prosthetics, virtual reality, and professional sports. Two commonly utilized types of strain sensors are capacitive and resistive strain gauges, owing to their low production cost, simplified circuitry, and ease of construction. While resistive strain gauges exhibit high sensitivity, they are prone to nonlinearity and hysteresis. On the other hand, capacitive strain gauges demonstrate linear behavior with minimal hysteresis but offer lower sensitivity. In this study, we capitalize on the exceptional properties of carbon nanotubes, including high mechanical strength, electrical conductivity, and thermal stability, along with using polyaniline as an exemplary conductive polymer. These materials are employed as a reinforcing phase within the polymer matrix, while the dielectric layer is comprised of Ecoflex® 00-30. An interdigitated pattern is specifically designed for this strain gauge to enhance sensitivity. Through this research, we aim to develop a flexible and stretchable strain sensor with enhanced sensitivity and improved performance characteristics.

---

Keywords :

gauge factor, strain sensor, tensile strength, wearable flexible.

---

References :

1. Yao, S., Zhu, Y., 2014. Wearable multifunctional sensors using printed stretchable conductors made of silver nanowires. Nanoscale 6(4), 2345-2352.
2. Yan, C., Wang, J., Kang, W., Cui, M., Wang, X., Foo, C.Y., Chee, K.J., Lee, P.S., 2014. Highly stretchable piezoresistive graphene–nanocellulose nanopaper for strain sensors. Advanced materials 26(13), 2022-2027.
3. Morteza Amjadi1, Yong Jin Yoon2 and Inkyu Park1. Nanotechnology 26 (2015), Ultra-stretchable and skin-mountable strain sensors using carbon nanotubes–Ecoflex nanocomposites.
4. Morteza Amjadi, Aekachan Pichitpajongkit, Sangjun Lee, VOL.8’NO. 5’ 5154–5163’ 2014, Highly Stretchable and Sensitive Strain Sensor Based on Silver Nanowire_Elastomer Nanocomposite
5. Hosseini, S., et al. (2022). “A sensitive and flexible interdigitated capacitive strain gauge based on carbon nanofiber/PANI/silicone rubber nanocomposite for body motion monitoring.” Materials Research Express 9(6): 065605.
6. Frutiger, A., Muth, J.T., Vogt, D.M., Mengüç, Y., Campo, A., Valentine, A.D., Walsh, C.J., Lewis, J.A., 2015. Capacitive soft strain sensors via multicore–shell fiber printing. Advanced materials 27(15), 2440-2446.
7. Cai, L. Song, P. Luan, Q. Zhang, Sci. Rep. 2013, 3, 3048, super stretchable, Transparent Carbon Nanotube-Based Capacitive Strain Sensors for Human Motion Detection
8. Wallbrink, C., et al. (2023). “Application of an advanced piezoelectric strain sensor for crack closure measurement.” International Journal of Fatigue 167: 107286.
9. Villafuerte, J., et al. (2023). “Boosting the piezoelectric coefficients of flexible dynamic strain sensors made of chemically-deposited ZnO nanowires using compensatory Sb doping.” Nano Energy 114: 108599.
10. Stretchable, Skin-Mountable, and Wearable Strain Sensors and Their Potential Applications: A Review 2016
11. Wearable and Transparent Capacitive Strain Sensor with High Sensitivity Based on Patterned Ag Nanowire Networks- 2017
12. Norouzi, M., et al. (2023). “Characterization and Biological Evaluation of New PLGA/Fibrin/Lignin Biocomposite Electrospun Scaffolds.” Physica Scripta, doi.org/10.1088/1402-4896/aceabc.
13. Norouzi, M., et al. (2021). “Adipose-derived stem cells growth and proliferation enhancement using poly (lactic-co-glycolic acid)(PLGA)/Fibrin nanofiber mats.” Journal of Applied Biotechnology Reports 8(4): 361-369. 10.30491/jabr.2020.223551.1199
14. Mehmet O. Tas, Mark A. Baker, Mateus G. Masteghin, ACS Appl. Mater 2019, Highly Stretchable, Directionally Oriented Carbon Nanotube/PDMS Conductive Films with Enhanced Sensitivity as Wearable Strain Sensors
15. A Highly Elastic, Capacitive Strain Gauge Based on Percolating Nanotube Networks- 2012
16. Recent Developments in Bio-monitoring via Advanced Polymer Nanocomposite-based Wearable Strain Sensors- 2018
17. Zohreh Homayounfar1 and Trisha L. Andrew1 © 2019 Society for Laboratory, Wearable Sensors for Monitoring Human Motion: A Review on Mechanisms, Materials, and Challenges
18. Rasheed, A.; Howe, J. Y.; The efficiency of the oxidation of carbon nanofibers with various oxidizing agents. Carbon 2007, 45, 1072-1080.
19. Guha, A.; Lu, W.; Zawodzinski, Surface-modified carbons as platinum catalyst support for PEM fuel cells. Carbon 2007, 45, 1506-1517.
20. Moumita Kotal, Awalendra K Thakur, Polyaniline-Carbon Nanofiber Composite by Chemical Grafting Approach and Its Supercapacitor Application, 10.1021/am4014049, 2013
21. Mohamadsharifi, A., et al. (2023). “High-Efficiency Inertial Separation of Microparticles Using Elevated Columned Reservoirs and Vortex Technique for Lab-on-a-Chip Applications.” ACS Omega 8(31): 28628-28639, doi.org/10.1021/acsomega.3c03136.