An adhesive and self-healable hydrogel with high stretchability and compressibility for human motion detection

Hydrogel strain sensors have attracted tremendous interest in artificial intelligence and human health monitoring for their large stretchability, good biocompatibility and self-healing capability. However, most epidermal strain sensors suffer from a poor device-skin interface, resulting in unreliability in the signal recording. Here, we prepared a self-adhesive, stretchable and compressible hydrogel consisting of dynamic cross-linked multi-walled carbon nanotubes , polyvinyl alcohol and polyacrylamide. The hydrogel formed a stable device-skin interface without any fixation assistance and thus allowed stable human motion signal recording from walking to facial expression. The hydrogel sensors exhibited a large sensing range of 500 % with a high gauge factor of 4.02 at 300-500 % tensile strain and a compressibility up to 70 %. In addition, the hydrogel is self-healable, and the conductivity of the hydrogel can be restored within 730 ms. At last, the hydrogel sensors were applied in human motion detection from vital throat vibration to walking, which paves the way for their practical applications in health monitoring and human-machine interactions.