Hybridized Hydrogen\nBonding Strategy to Construct\nAntifreezing Hydrogels for Wearable Sensors

Hydrogels are widely used across various fields, creating\na demand\nfor materials capable of withstanding freezing conditions. Most existing\nantifreezing hydrogels rely on small-molecule additives or are organogels,\nwhich frequently encounter environmental concerns due to potential\ntoxicity and exhibit poor long-term stability in harsh conditions.\nIn this study, we propose a hybridized hydrogen bonding strategy to\ndevelop antifreezing hydrogels without the need for small-molecule\nadditives. The freezing resistance is achieved through interactions\nbetween the hydrogel’s polar functional groups (the −COOH\ngroup of poly(acrylic acid), the −CO– group of polyvinylpyrrolidone,\nand the −OH group of phytic acid) and water molecules, which\nmodify the distribution of hydrogen bonds within the system. These\nhydrogels demonstrate excellent mechanical resilience (92%) and conductivity,\nboth of which are maintained at subzero temperatures. Additionally,\nflexible sensors made from these hydrogels exhibit reliable signal\nstability in low-temperature environments. This work presents an effective\nstrategy for improving the freezing resistance of hydrogels, advancing\nour understanding of antifreezing mechanisms, and providing practical\ninsights for future applications, particularly in wearable sensor\ntechnologies.