Ultra‐Sensitive and Highly Stretchable Strain Sensors for Monitoring of Human Physiology

Abstract The flexible strain sensors have potential applications in advanced electronics, health monitoring systems, wearable sensors, robotics, and human–machine interfaces. The development of highly sensitive, stretchable, and durable strain sensors is a challenging task for researchers. However, the sensors with a detection range from large strain to minute deflection are imperative for human‐interactive applications. This work has demonstrated a facile method of sensor fabrication, which use reduced graphene oxide (rGO) as sensing material and silicone sealant as a flexible substrate. Few‐layer rGO is synthesized by electrochemical exfoliation of pencil lead. The fabricated sensors have a gauge factor higher than 4000 and durability longer than 1600 cycles at 100% strain. At the same time, developed strain sensors exhibit detection capability over a wide range of strain (0–120%), which is an essential requirement of wearable sensors. To the best of the authors’ knowledge, fewer works have reported strain sensors that have ultra‐high gauge factor (≥4000) in combination with high stretchability (>100%). Utilizing the ultra‐sensitivity and sub‐second response time of the rGO‐sealants, these wearable sensors are used to monitor physical activities, heartbeats, and finger touches.