High linearity and low hysteresis LMPs/MXene/AgNWs strain sensor for human motion detection

Abstract

Resistive strain sensors show great potential in motion detection, medicine and healthcare, and human–machine interaction owing to their ease of fabrication, simple structure, and adjustable electrical performance. However, developing high-performance flexible resistive strain sensors with high sensitivity, high linearity, and low hysteresis remains a challenge. In this work, we report an LMPs (liquid metal particles)/MXene/AgNWs strain sensor (LMA strain sensor) with high sensitivity (GF = 6.339), high linearity (R2 = 0.982 24), and low hysteresis (0.452%). In this process, AgNWs act as a bridge between the MXene nanosheets, and the change in contact area of the MXene nanosheets under stretching endows the sensor with high sensitivity. The aggregated LMPs function as a structural framework, capitalizing on their intrinsic fluidic characteristics to serve as an adhesive between silver nanowires (AgNWs) and MXene nanosheets. This approach effectively minimizes the interstitial spaces between AgNWs and MXene. The formation of Ti-O → Ga3+ coordination bonds between MXene nanosheets and LMPs has strengthened the interfacial interactions. Consequently, the sensor demonstrates superior linearity and low hysteresis. In addition, a sensitive layer with a buckled structure is obtained by stretch-release. The buckled structure inhibits inhomogeneous and irreversible connection losses of the sensitive material, further improving the sensor's mechanical durability. LMA strain sensors can accurately detect various human activities such as breathing detection, motion detection, and expression detection. This work will provide an avenue for developing high-performance strain sensors.