Triple‐Asymmetric Flexible Strain Sensor Based on High‐aligned Ni Nanowire Arrays with Opposite Resistance Responding for Multidimensional Motions Detection

Abstract Herein, a triple‐asymmetric flexible strain sensor by using the single‐layered high‐aligned Ni‐nanowire arrays is proposed for the applications of monitoring multidimensional motions of human joints. The triple‐asymmetric structures consist of a spatially ordering distribution of Ni nanowires (NWs) and double position asymmetric distributions of the Ni NWs in width and thickness direction of sensor. Because Ni NWs are isolated from each other, the resistance change of the sensor is by tunneling effect. The resistance values of the proposed sensor decrease with the increasing of stretching strain, which is different from that of the common flexible strain sensors, and the maximum absolute valve of gauge factor is 35. Furthermore, the proposed sensor has a good bending sensitivity, ranging from 90° to −90°, and minimum resolution angle of 5° in out‐plane bending. Benefiting from the asymmetric structures and tunneling effect, the complex movements of human joints (such as up‐down bending, left‐right swing, and rotating of wrist) are successfully detected. The practical applicability in real‐time monitoring and the processes of handwriting are also shown. Therefore, this proposed sensor is believed to have great potential in future development of micro‐motion monitoring, wearable electronics, and artificial intelligence.