Rapid preparation of dynamic-crosslinked nanocomposite hydrogel sensors with efficiency self-healing and adhesion properties for elderly health and sleep management

Multifunctional conductive hydrogels exhibit tremendous potential for applications in human–machine interfaces, flexible electronic devices and soft robotics. However, the time-consuming and energy-intensive preparation process, as well as the inefficient and unstable self-healing capabilities, limit their practicality and reusability. Herein, we utilized lignin sulfonate (LS)-Fe3+ dynamic redox system to induce the generation of ammonium persulfate (APS) radicals at room temperature. Additionally, the polymerization of acrylamide (AM), sodium acrylate (AAS), and 3-acrylamidophenylboronic acid (APBA) formed polymer networks through multiple dynamic crosslinking via the synergistic interactions of Fe3+ and cellulose nanocrystals (CNC). The dynamic and reversible boronic ester bonds, ion coordination bonds, and hydrogen bonds endowed the hydrogel with high stretchability (1170 %), low hysteresis and efficient self-healing (91.76 %, 2 h) capability. Interestingly, the intermediate catechol groups generated by the LS-Fe3+ dynamic catalytic system provided the hydrogel with repeatable and reliable adhesive performance. Thanks to the excellent ionically conductivity, the fabricated hydrogel-based sensors exhibited a wide sensing range (500 %), rapid response time (139 ms), and high sensitivity (GF = 8.98), that accomplished specific voice recognition and subtle body motion detection for real-time elderly health and sleep management. This multifunctional hydrogel is of great significance for efficiently developing prolonged lifespan wearable electronics and healthcare flexible devices.