Highly Sensitive, Wide-Range Pressure Sensor Based on Negative Poissons Ratio for Human Motion Detection

Flexible wearable materials can be attached to human skin to collect a range of health information, such as wrist rotation, finger joint movement, knee flexion, and so on. Moreover, facialmuscle-based signal monitoring can infer people's emotional expressions, which has a wide range of applications. At present, it is difficult for one sensor to realize the interactive information monitoring of multiple parts of the human body, which is caused by the contradiction between sensitivity and range. In this work, an innovative method of mechanical structure is proposed. A PDMS elastomer with negative Poisson's ratio (NPR) is embedded in the graphene-silicon rubber foam composite (rGO-PDMS/SR) in a simple and low-cost process, which improves the mechanical performance and resistance variation range effectively. The performance test results show that compared with ordinary graphene-silicon rubber composites (rGO-SR), the resistance variation range of the rGO-PDMS/SR has expanded by six times, which has high linear sensitivities of 7.0838 kPa(-1) at 0-50 kPa and 0.0168 kPa(-1) at 50-250 kPa. In addition, the composite shows reliable stability during cyclic compression. By analyzing the resistance change mechanism of the sensor, the explicit expression between the composite material performance parameters and the resistance is obtained. The results of human interaction experiments show that the sensor can meet the requirements of signal detection at nine different positions of the human body, including facial expression judgment, motion state monitoring, and other fields, which indicates good human interaction performance.