Polyvinyl alcohol modified plant fiber hydrogel pressure and strain dual-model sensors for biomedical signal detection

Flexible and stretchable hydrogels have become promising materials for wearable biomedical devices used in continuous health monitoring. A simple and effective ball-milling method is proposed to create conductive, biocompatible polyvinyl alcohol (PVA) hydrogels modified with plant fibers and carbon nanotubes (CNTs) for dual-model wearable devices. The plant fibers and CNTs disperse within the PVA network, providing excellent stretchability (up to 4200% tensile strain), self-healing, and conductivity. These hydrogels can be used for assembling and repairing electrical circuits and serve as sensing elastomers for capacitive strain sensors with high sensitivity, durability, and wide strain range. After high temperature treatment, a conductive and compressible porous PVA/PF@CNT sponge can be obtained from PVA/PF@CNT hydrogel, which can be assembled as piezoresistive pressure sensors with a sensitivity of 0.89 kPa⁻¹. These sensors enable real-time monitoring of human biological signals, including joint movements, facial expressions, and throat activity.