Lin Jiawei, Chen Zhiwen, Zhuang Qibin, Chen Songyue, Zhu Cuicui, Wei Yimin, Wang Shaofei, Wu Dezhi
Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361101, China.
Fujian Science & Technology Innovation Laboratory for Energy Devices of China (21C LAB), Ningde 352100, China.
ACS Appl Mater Interfaces. 2023 Oct 25;15(42):49642-49652. doi: 10.1021/acsami.3c10975. Epub 2023 Oct 13.
Flexible pressure sensors possess vast potential for various applications such as new energy batteries, aerospace engines, and rescue robots owing to their exceptional flexibility and adaptability. However, the existing sensors face significant challenges in maintaining long-term reliability and environmental resilience when operating in harsh environments with variable temperatures and high pressures (∼MPa), mainly due to possible mechanical mismatch and structural instability. Here, we propose a composite scheme for a flexible piezoresistive pressure sensor to improve its robustness by utilizing material design of near-zero temperature coefficient of resistance (TCR), radial gradient pressure-dividing microstructure, and flexible interface bonding process. The sensing layer comprising multiwalled carbon nanotubes (MWCNTs), graphite (GP), and thermoplastic polyurethane (TPU) was optimized to achieve a near-zero temperature coefficient of resistance over a temperature range of 25-70 °C, while the radial gradient microstructure layout based on pressure division increases the range of pressure up to 2 MPa. Furthermore, a flexible interface bonding process introduces a self-soluble transition layer by direct-writing TPU bonding solution at the bonding interface, which enables the sensor to achieve signal fluctuations as low as 0.6% and a high interface strength of up to 1200 kPa. Moreover, it has been further validated for its capability of monitoring the physiological signals of athletes as well as the long-term reliable environmental resilience of the expansion pressure of the power cell. This work demonstrates that the proposed scheme sheds new light on the design of robust pressure sensors for harsh environments.
柔性压力传感器因其卓越的柔韧性和适应性，在新能源电池、航空航天发动机和救援机器人等各种应用中具有巨大潜力。然而，现有的传感器在温度变化和高压（约MPa）的恶劣环境中运行时，在保持长期可靠性和环境适应性方面面临重大挑战，这主要是由于可能存在的机械失配和结构不稳定性。在此，我们提出一种用于柔性压阻式压力传感器的复合方案，通过利用近零电阻温度系数（TCR）的材料设计、径向梯度分压微结构和柔性界面键合工艺来提高其鲁棒性。对由多壁碳纳米管（MWCNT）、石墨（GP）和热塑性聚氨酯（TPU）组成的传感层进行了优化，以在25至70°C的温度范围内实现近零电阻温度系数，而基于分压的径向梯度微结构布局将压力范围提高到2MPa。此外，一种柔性界面键合工艺通过在键合界面直接写入TPU键合溶液引入了自溶性过渡层，这使传感器能够实现低至0.6%的信号波动和高达1200kPa的高界面强度。此外，它还进一步验证了其监测运动员生理信号的能力以及对动力电池膨胀压力的长期可靠环境适应性。这项工作表明，所提出的方案为恶劣环境下鲁棒压力传感器的设计提供了新的思路。
