Wu Shuang, Kim Doyun, Tang Xiaoqi, King Martin W, Zhu Yong
Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA.
Wilson College of Textiles, North Carolina State University, Raleigh, NC 27695, USA.
Mater Horiz. 2024 Oct 14;11(20):5070-5080. doi: 10.1039/d4mh00757c.
Soft and stretchable strain sensors have found wide applications in health monitoring, motion tracking, and robotic sensing. There is a growing demand for strain sensors in amphibious environments, such as implantable sensors, wearable sensors for swimmers/divers, and underwater robotic sensors. However, developing a sensitive, stretchable, and robust amphibious strain sensor remains challenging. This work presents an encapsulated stretchable amphibious strain sensor. The conductive layer, made of silver nanowires embedded below the surface of polydimethylsiloxane, was sandwiched by two layers of thermoplastic polyurethane. Periodic sharp cuts were introduced to change the direction of flow from across the sensor to along the conductive path defined by the opening cracks. The crack advancing and opening is controlled by a unique combination of weak/strong interfaces within the sandwich structure. The cut design and the interfacial interactions between the layers were investigated. The strain sensor exhibited a high gauge factor up to 289, a linear sensing response, a fast response time (53 ms), excellent robustness against over-strain, and stability after 16 000 loading cycles and 20 days in an aqueous saline solution. The functionality of this amphibious strain sensor was demonstrated by tracking the motion of a robotic fish, undertaking language recognition underwater, and monitoring the blood pressure of a porcine aorta. This illustrates the promising potential for this strain sensor for both underwater use and surgically implantable applications.
柔软且可拉伸的应变传感器在健康监测、运动跟踪和机器人传感等领域有着广泛的应用。在两栖环境中，对应变传感器的需求日益增长，例如可植入传感器、供游泳者/潜水员使用的可穿戴传感器以及水下机器人传感器。然而，开发一种灵敏、可拉伸且坚固的两栖应变传感器仍然具有挑战性。这项工作展示了一种封装式可拉伸两栖应变传感器。由嵌入聚二甲基硅氧烷表面下方的银纳米线制成的导电层夹在两层热塑性聚氨酯之间。引入周期性的尖锐切口，以改变电流方向，使其从横穿传感器变为沿着由开口裂缝定义的导电路径流动。裂缝的推进和开口由夹层结构内弱/强界面的独特组合控制。研究了切口设计和各层之间的界面相互作用。该应变传感器表现出高达289的高应变系数、线性传感响应、快速响应时间（53毫秒）、对过应变的出色鲁棒性以及在16000次加载循环和在盐水溶液中放置20天后的稳定性。通过跟踪机器鱼的运动、进行水下语言识别以及监测猪主动脉血压，证明了这种两栖应变传感器的功能。这说明了这种应变传感器在水下使用和手术植入应用方面的广阔前景。
