A High-Performance Stretchable Hydrogel for Advanced Health Technology: Antifreezing, Self-Healing Electronics in Thermal Therapy and Motion Sensing

High-performance multifunctional hydrogels exhibit immense potential for transforming health technology, particularly through applications in wearable healthcare devices and therapeutic systems. These materials are valued for their ability to closely mimic biological tissues while integrating key functional attributes. However, achieving a combination of outstanding mechanical strength, high conductivity, and self-healing properties in a single hydrogel remains challenging. In this study, we present a one-pot synthesis method for fabricating the PVA/PAM/NaCl/CB (PPNC) hydrogel, composed of poly(vinyl alcohol) (PVA), polyacrylamide (PAM), sodium chloride, and carbon black. By leveraging physical entanglement within the PPNC network along with dynamic chemical bonds and reversible physical interactions, the hydrogel achieves superior mechanical robustness and self-healing properties. The PPNC hydrogel demonstrates impressive mechanical performance, with a tensile strength of 688 kPa and elongation over 700%, alongside high electrical conductivity (4.9 S·m–1 at 25 °C). Additionally, its exceptional antifreezing capabilities allow it to maintain these properties at −20 °C. As a proof-of-concept, the hydrogel has been successfully applied as a motion-sensing device, accurately tracking human movement for health monitoring, and as a heating device, delivering effective thermal therapy to the human body. These findings highlight the hydrogel’s significant potential in healthcare innovation, including wearable technology, biological sensors, and therapeutic devices.