Direct ink writing of a graphene/CNT/silicone composite strain sensor with a near-zero temperature coefficient of resistance

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 1; no. 21; pp. 8226 - 8233
• Main Authors: Zhu, Wei-Bin, Xue, Shan-Shan, Zhang, Hao, Wang, You-Yong, Huang, Pei, Tang, Zhen-Hua, Li, Yuan-Qing, Fu, Shao-Yun
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.06.2022
• Subjects: Carbon nanotubes; Elastomers; Graphene; High temperature; Human motion; Motion perception; Positive temperature coefficient; Response time; Sensors; Silicone resins; Stability; Temperature; Wear resistance; Zero temperature coefficient
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/d2tc00918h

The development of wearable strain sensors with a zero temperature coefficient of resistance (TCR), which is crucial to overcome the problem of temperature disturbance, has been scarcely studied. Herein, highly stretchable graphene nanoplatelet (GNP)/carbon nanotube (CNT)/silicone elastomer (GCE) fibers are successfully prepared via a facile direct ink writing technique. The GCE fibers fabricated consist of CNTs and GNPs having a negative temperature coefficient (NTC) and a positive temperature coefficient (PTC), respectively. As a result, the obtained GCE fiber by adjusting the mass ratio of CNTs and GNPs shows a near-zero TCR (1.14 × 10 −4 °C), which is the lowest one compared with the reported values in the literature. Besides, the GCE strain sensor exhibits the highest sensitivity (gauge factor (GF) = 14550.2 for 100% strain) compared with the data reported previously, and a wide working range (1 to 100%), a low detecting limit (1% strain), a quick response time (170 ms) and a high durability (after 10 000 loops). In addition, the GCE strain sensor shows an excellent electrical stability under external conditions including longstanding storage and humidity/water exposure. Finally, various human movements are detected under water and high temperature conditions to demonstrate the outstanding sensing performance and response stability of the GCE strain sensor. Using a facile direct ink writing technique, highly stretchable graphene nanoplatelet (GNP)/carbon nanotube (CNT)/silicone elastomer (GCE) fiber-shaped strain sensors are successfully prepared with a near-zero temperature coefficient of resistance.