Intrinsically antifreeze conductive hydrogels based on thermo-responsive property for low-temperature flexible...

Conductive hydrogels have significant potential in health monitoring and flexible wearable devices, but their performance is often compromised at sub-zero temperatures due to freezing. Traditional antifreeze strategies rely on additives, which can lead to leakage and toxicity issues. This study introduces a novel intrinsically antifreeze hydrogel by integrating thermo-responsive Poloxamer 407 (P407) into an acrylic acid (AA) and sodium dodecyl sulfate (SDS) system. The resulting PAA-P407@SDS hydrogel exhibits excellent mechanical properties (1458 % strain at break, 317.5 kPa stress) and high sensitivity (Gauge Factor of 4.01), enabling effective monitoring of human joint movements, speech, and subtle motions. P407 disrupts the hydrogen-bond network of water, preventing crystallization and maintaining functionality at temperatures as low as -20 °C without additional antifreeze agents. Density Functional Theory (DFT) calculations confirm the mechanism, while applications in Morse code transmission and writing sensors demonstrate versatility. This work provides a scalable strategy for developing hydrogels resilient to extreme cold, ideal for wearable electronics and emergency communication.