Ma Xin, Zhang Qi, Guo Peng, Tong Xiaoshan, Zhao Yulong, Wang Aiying
State Key Laboratory for Mechanical Manufacturing Systems, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
ACS Appl Mater Interfaces. 2020 Oct 7;12(40):45549-45557. doi: 10.1021/acsami.0c12073. Epub 2020 Sep 22.
Usually, two-dimensional (2D) flexible strain sensors based on cracks have very high sensitivities but small measuring ranges, while the three-dimensional (3D) ones behave in the opposite way. Here, by utilizing the large residual compressive stress of an amorphous carbon (a-C) film and the flexibility of polydimethylsiloxane (PDMS), we developed a facile and economic strategy to fabricate a high-sensitive a-C/PDMS stretchable strain sensor. Results showed that for the first time, the a-C film ranging from 25 nm to 1 μm changed the shape and orientation of conductive scales, as well as made a one-step 2D-to-3D electrical junction transformation in integrated sensors. In particular, the sensor with a 1 μm thick a-C film exhibited the best comprehensive performance, displaying a maximum gauge factor of 746.7 and strain range up to 0.5. However, the linearity decreased slightly as the strain range went beyond 0.43. Additionally, the sensor showed a satisfactory repeatability for 5000 cycles, together with excellent time and temperature drift performances at zero position of 75 ppm full scale (FS) and 25 ppm FS·°C in the range of -20 to 155 °C, respectively. The sensor has large potentials for wearable devices used in the monitoring of various human motions and physiological signals.
通常，基于裂纹的二维（2D）柔性应变传感器具有非常高的灵敏度，但测量范围较小，而三维（3D）柔性应变传感器的情况则相反。在此，通过利用非晶碳（a-C）薄膜的大残余压应力和聚二甲基硅氧烷（PDMS）的柔韧性，我们开发了一种简便且经济的策略来制造高灵敏度的a-C/PDMS可拉伸应变传感器。结果表明，首次实现了厚度在25纳米至1微米范围内的a-C薄膜改变导电鳞片的形状和取向，并在集成传感器中实现了一步式二维到三维的电结转变。特别是，具有1微米厚a-C薄膜的传感器表现出最佳的综合性能，最大应变系数为746.7，应变范围高达0.5。然而，当应变范围超过0.43时，线性度略有下降。此外，该传感器在5000次循环中表现出令人满意的重复性，在-20至155°C范围内零位置的时间漂移和温度漂移性能也非常出色，分别为满量程（FS）的75 ppm和25 ppm/°C。该传感器在用于监测各种人体运动和生理信号的可穿戴设备方面具有巨大潜力。
