Tough and Self-Adhesive Nanolignin Multifunctional Hydrogel-Based Strain Sensor for HumanMachine Interaction

Conductive hydrogels are crucial to intelligent robotics and wearable devices, but their adoption is hindered by limited functionality and energy-intensive petrochemical synthesis. To address this challenge, a nanolignins (NLs)-reinforced polyacrylamide hydrogel (NL@PAM) was prepared via a green strategy at room temperature. Lignin nanoparticles were synthesized by a green method and integrated into the polyacrylamide network through extensive hydrogen bonding and interchain interactions. This structure imparts the NL@PAM hydrogel with a unique combination of mechanical and functional properties, including high tensile strength (1.32 MPa), ultrahigh stretchability (1880%), strong self-adhesion (196 kPa), and high ionic conductivity (13.96 mS cm^-1). As a demonstration, the hydrogel was used as a wearable sensor on human fingers; it converted real-time finger movements into control signals for a robotic arm, which faithfully replicated the gestures. These results demonstrate a high-performance multifunctional hydrogel and establish a sustainable paradigm for soft electronics, leveraging green chemistry and renewable biomass for future intelligent systems.