Zr4+-reinforced zwitterionic hydrogels with multiple dynamic networks for ultrasensitive strain sensing in next-generation wearable electronics

Zwitterionic hydrogels have emerged as promising candidates for next-generation wearable electronics in human motion monitoring and healthcare diagnostics. Nevertheless, the inherent weak mechanical properties, short of adhesion, and lack of self-healing ability of traditional hydrogels result in low detection accuracy and short service life of the hydrogel sensors. Herein, we developed an innovative multiple-dynamic hydrogel system through the co-incorporation of hydrophobic micelles, Zr 4+ ions, and calcium lignosulfonate as synergistic crosslinkers. The multi-physical interactions (coordination bonds, hydrogen bonding, and electrostatic interactions) endow the hydrogel with good mechanical strength (111 kPa), remarkable self-healing capacity (100 % recovery within 6 h), and great self-adhesion to various substrates. Benefiting from its interconnected porous structure and mobile ion (Zr 4+ /Na + /Cl − ), the hydrogel demonstrated good ionic conductivity (2.9 mS/m). The resultant strain sensor manifested outstanding sensing performance with gauge factors of 3.4 (0–200 % strain) and 14 (400–800 % strain), respectively. Notably, the self-healed hydrogel maintained the stable and accurate sensing performance as before. Practical demonstrations include precise detection of both subtle physiological signals (pulse waveforms, vocal vibrations) and large joint movements. When integrated into smart gloves, the system successfully decoded complex hand gestures. This multifunctional hydrogel platform opens new avenues for developing high-performance wearable devices in healthcare monitoring and human-machine interfaces.