This paper introduces a flexible capacitive strain sensor with three-dimensional (3D) interdigital electrodes fabricated using vertically aligned carbon nanotubes. This design addresses limitations of existing strain sensors by achieving low hysteresis, pressure insensitivity, and high transparency. The sensor demonstrates ultralow hysteresis (0.35%), excellent pressure-insensitive performance (less than 0.8%), fast response (60 ms), good long-term stability, and good transparency. Its application in monitoring various human activities, including finger, knee, elbow, wrist, and neck bending, as well as mouth-opening, is successfully demonstrated, highlighting its potential for human motion detection, soft robotics, and medical care.

Xiaoyi Wang, Yang Deng, Peng Jiang, Xingru Chen, Hongyu Yu