A High-Sensitivity MXene Tactile Sensor with Dynamic Point-Contact Networks for a Wearable Healthcare Device

The self-stacking of the MXene material can diminish its interlayer spacing and active surface area, thereby diminishing the sensitivity and response speed of pressure sensors. Here, we introduce a high-performance flexible tactile sensor utilizing a composite of MXene, polystyrene (PS) microspheres, and bacterial cellulose (BC). PS microspheres are integrated within the MXene nanosheet layers to mitigate the self-stacking. By employing an innovative point-to-point conductive network design, the self-aggregation issue of MXene materials is effectively mitigated, leading to the formation of dynamic point-contact structures among PS microspheres. This configuration notably enhances detection sensitivity within the low-pressure range to 568.8 kPa^-1 (20-200 Pa). Furthermore, the incorporation of BC enhances the interfacial bonding strength through hydrogen bonding, thereby enhancing sensor stability. The sensor exhibits a rapid response time of 29 ms, a wide detection range of up to 0-50 kPa, a low limit of detection of 2 Pa, and consistent signal stability over 20,000 cycles. It has demonstrated the capability to monitor a broad spectrum of physiological activities, including joint movements, facial microexpressions, and radial pulse. Integration with wireless transmission technology enables remote health monitoring, flexible touch keyboard functionality, and human-computer interaction. Additionally, the electromyography (EMG) skin sensor based on the MXene/PS/BC (MPB) composite film accurately distinguishes muscle movements, gestures, acoustic vibrations, and facial microexpressions by detecting surface EMG signals. This comprehensive approach offers a comprehensive solution for wearable medical devices that combine high sensitivity with practicality.