Ultra-stretchable, adhesive, and self-healing MXene/polyampholytes hydrogel as flexible and wearable epidermal sensors

The hydrogel-based epidermal sensors have attracted tremendous attention due to their versatile potential applications in soft robotics, personal healthcare monitoring, and electronic skins. However, it remains a critical challenge for hydrogel-based sensors to simultaneously achieve self-healing capability and adhesiveness for full-scale human motion biomonitoring. Herein, we proposed a multifunctional MXene/polyampholytes nanocomposite hydrogel. The main network of this hydrogel was formed by the one-step radical polymerization of cationic monomer and anionic monomer. The simultaneous strong and weak ionic bonds-based crosslinking inside this hydrogel endowed it outstanding stretchable, tough, self-healing, adhesive properties, while the introduction of MXene further guaranteed the excellent mechanical properties and conductivity of this hydrogel. Our further exploration of this MXene/polyampholytes in the application as wearable epidermal sensor strongly proved its durable accuracy and sensitivity for the detection of human motions. This epidermal sensor also could be assembled to the detector of the daily activity monitor of Attention-deficit hyperactivity disorder (ADHD) patients, which could be utilized to aid the ADHD treatment by remindering the patients to pay attention to their actions. Our work shed a new light on the development of eco-friendly wearable sensor for the personalized healthcare monitoring, human–machine interfaces, and artificial intelligence.