School of Materials Science and Engineering , Zhengzhou University , Zhengzhou 450001 , China.
Center for Advanced Materials Research, School of Materials and Chemical Engineering , Zhongyuan University of Technology , Zhengzhou 450007 , China.
ACS Appl Mater Interfaces. 2019 Feb 20;11(7):7405-7414. doi: 10.1021/acsami.8b20768. Epub 2019 Feb 8.
Flexible strain sensors have attracted tremendous interest due to their potential application as intelligent wearable sensing devices. Among them, crack-based flexible strain sensors have been studied extensively owing to their ultrahigh sensitivity. Nevertheless, the detection range of a crack-based sensor is quite narrow, limiting its application. In this work, a stretchable strain sensor based on a designed crack structure was fabricated by spray-coating carbon nanotube (CNT) ink onto an electrospun thermoplastic polyurethane (TPU) fibrous mat and prestretching treatment to overcome the trade-off relationship. Our sensor exhibited combined features of high sensitivity in a greatly widened workable sensing range [a gauge factor of 428.5 within 100% strain, 9268.8 for a strain of 100-220%, and larger than 83982.8 for a strain of 220-300%], a fast response time (about 70 ms), superior durability (>10 000 stretching-releasing cycles), and excellent response toward bending. The microstructural evolution of CNT branches extending from two edges of the cracks and the excellent stretchability of TPU fibrous mats are mainly related to the remarkable sensing properties. Our sensor is then assembled to detect various human motions and physical vibrational signals, demonstrating its potential applications in intelligent devices, electronic skins, and wearable healthcare monitors.
由于在智能可穿戴传感设备方面的潜在应用，柔性应变传感器受到了极大的关注。其中，基于裂纹的柔性应变传感器因其超高的灵敏度而得到了广泛的研究。然而，基于裂纹的传感器的检测范围相当狭窄，限制了其应用。在这项工作中，通过将碳纳米管（CNT）墨水喷涂到静电纺丝热塑性聚氨酯（TPU）纤维垫上，并进行预拉伸处理，制备了一种基于设计的裂纹结构的可拉伸应变传感器，以克服这种权衡关系。我们的传感器具有高灵敏度和大大拓宽的工作感应范围的综合特性[应变 100%时的灵敏度为 428.5，应变 100-220%时为 9268.8，应变 220-300%时大于 83982.8]、快速响应时间（约 70 ms）、出色的耐用性（>10000 次拉伸-释放循环）以及对弯曲的优异响应。裂纹两边缘处 CNT 分支的扩展和 TPU 纤维垫的优异拉伸性主要与显著的传感性能有关。我们的传感器随后被组装用于检测各种人体运动和物理振动信号，展示了其在智能设备、电子皮肤和可穿戴式医疗监测器中的潜在应用。
