Multifunctional conductive hydrogel based on carboxymethyl cellulose/oxidized sodium alginate for machine...

Multifunctional hydrogels have shown great promise in advanced wearable sensing technologies; however, their performance under real-world sweaty and dynamic conditions remains a significant challenge. In this study, a highly conductive and adhesive hydrogel was developed using poly(AM-co-AA), carboxymethyl cellulose (CMC), oxidized sodium alginate (OSA), and polydopamine-modified carbon nanotubes (PDA-CNT). Featuring a dual dynamic cross-linking system based on reversible Schiff base bonds and strong hydrogen bonding, the hydrogel demonstrates high mechanical toughness (2416 kJ/m³), excellent stretchability (1829%), and stable electrical conductivity (1.5 S/m). It exhibits outstanding sweat resistance, maintaining strong adhesion and reliable sensing performance even during intense physical activities, along with high fatigue resistance over 10,000 deformation cycles, enabling long-term reliable monitoring. As a highly sensitive strain sensor, it offers multi-range gauge factors (up to 2.53) and accurately captures human motion and physiological signals without interference from sweat or motion artifacts. When integrated with machine learning algorithms, the sensor achieves a validation accuracy of 98.75%, providing real-time feedback on movement techniques and supporting personalized training optimization. Furthermore, the hydrogel demonstrates significant antibacterial properties and good biocompatibility, making it an ideal candidate for next-generation wearable electronic devices suited for long-term athletic training and high-sweat environments.