Wireless wearable system based on multifunctional conductive PEG-HEMA hydrogel with anti-freeze, anti-UV, self-healing, and self-adhesive performance for health monitoring

Abstract

Polymer gels, such as hydrogels, have been widely applied in biomedicine, flexible electronics, and soft robotics. However, due to the complexity of application environments, preparing hydrogels that can maintain comprehensive performance under harsh conditions remains a challenge. Herein, based on polyethylene glycol (PEG) and water as a mixed solvent and using hydroxyethyl methacrylate (HEMA) as a monomer, a conductive dual-network PEG-HEMA hydrogel with anti-freezing, anti-ultraviolet, self-healing, and self-adhesive functions was prepared. The results show that PEG-HEMA hydrogel remained unfrozen even at -20°C, with tensile strength and elongation at break of 49.946 KPa and 529.7%, high resolution (able to measure strains as low as 0.2%), good sensitivity and linearity (GF=1.076, R2=0.999), fatigue resistance (over 1000 cycles), and long-term storage capability (over one week). Furthermore, a small wireless wearable strain sensor system was developed by integrating the hydrogel with a microcontroller, which is capable of monitoring various human motion and physiological signals in real time and exhibiting excellent sensing performance. This work provides a straightforward approach for multifunctional hydrogels, and it is expected to attract widespread attention and applications in fields such as electronic skin, human-machine interaction, and human health monitoring.