Polysaccharide-based high-strength, self-healing and ultra-sensitive wearable sensors

As abundant, biodegradable, and biocompatible materials, polysaccharides have received great attention in many fields. Ionic conductive hydrogels based on sodium alginate and its derivatives have been extensively studied in the field of wearable sensors due to their low cost, non-toxic and biocompatible. However, the inherent low mechanical strength of hydrogels leads to poor accuracy and durability of electrical signals under high loads. Herein, the intelligent ionic hydrogels based on oxide sodium alginate (OSA), poly (acrylamide-co-acrylic acid) (PACA), and FeCl3 were synthesized by a simple one-pot method. Reversible imine and hydrogen bonds between OSA and PACA, and coordination interactions among PACA, OSA, and Fe3+ were successfully designed to provide hydrogels with excellent elongation at break (830%), strong tensile strength (370 kPa), and high self-healing efficiency (90%). They also show controlled conductivity and high tensile sensitivity (Gauge factor, GF=7.8) for accurate and stable detection of human movement and physiological stimuli. Given these findings, the developed polysaccharide-based hydrogels represent a great application prospect in strain sensors for wearable electronic devices, soft robotics, and human-machine interfaces.