High-performance fiber strain sensor of carbon nanotube/thermoplastic polyurethane@styrene butadiene styrene with a double percolated structure

Abstract

In this work, a high-performance fiber strain sensor is fabricated by constructing a double percolated structure, consisting of carbon nanotube (CNT)/thermoplastic polyurethane (TPU) continuous phase and styrene butadiene styrene (SBS) phase, incompatible with TPU (CNT/TPU@SBS). Compared with other similar fiber strain sensor systems without double percolated structure, the CNT/TPU@SBS sensor achieves a lower percolation threshold (0.38 wt.%) and higher electrical conductivity. The conductivity of 1%-CNT/TPU@SBS (4.12×10⁻³ S·m⁻¹) is two orders of magnitude higher than that of 1%-CNT/TPU (3.17×10⁻⁵ S·m⁻¹) at the same CNT loading of 1 wt.%. Due to double percolated structure, the 1%-CNT/TPU@SBS sensor exhibits a wide strain detection range (0.2%–100%) and an ultra-high sensitivity (maximum gauge factor (GF) is 32411 at 100% strain). Besides, the 1%-CNT/TPU@SBS sensor shows a high linearity (R² = 0.97) at 0%–20% strain, relatively fast response time (214 ms), and stability (500 loading/unloading cycles). The designed sensor can efficiently monitor physiological signals and movements and identify load distribution after being woven into a sensor array, showing broad application prospects in wearable electronics.

Graphical abstract

Keywords

double percolated structure / strain sensor / fiber / carbon nanotube / nanocomposite

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Acknowledgements

This work was supported by the National Natural Science Foundation of China (Grant No. 12102374), the National Key Research and Development Program (Grant No. 2019YFE0120300), the Sichuan Science and Technology Program (Grant No. 2021YFH0031), the International Cooperation Project of Chengdu (Grant No. 2019-GH02-00054-HZ), and the Innovative Research Team of SWPU (Grant No. 2017CXTD01).

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