Freeze-resistant multi-functional organohydrogel reinforced with bi-metallic MOFs for advanced strain sensors and flexible communication devices

Abstract

Hydrogel-based wearable electronics have attracted significant attention in recent years; however, their progress is hindered by shortcomings such as weak mechanical strength and poor freezing resistance. In this work, we have overcome on these limitations by presenting a highly stretchable and mechanically reinforced zinc zirconium bi-metallic metal organic frameworks (ZnZr Bi-MOFs) based double-network organohydrogel with excellent low-temperature tolerance and enhanced mechanical properties. The incorporation of ZnZr Bi-MOFs into a polyacrylamide (PAm) and polymethyl methacrylate (PMMA) double network, within an ethylene glycol (Eg)/water binary solvent system, through combined physical and chemical interactions, yields an organohydrogel with superior mechanical robustness (stretchability up to 2500%), high toughness (406 kJ/m³), and superior interfacial adhesion performance. Eg acts as an antifreeze agent, suppressing ice-crystal formation and enabling frost resistance to -20 °C. The organohydrogel also demonstrates remarkable electrical conductivity (0.35 S/m) and excellent strain-sensing performance, including a high gauge factor (GF = 7.58), rapid response/ recovery time (110/90 ms), and a wide detection range (0.5-800%), allowing precise monitoring of diverse deformations and human motions. Furthermore, when coupled with Morse code, the sensor functions as a freezing-tolerant communication platform capable of encrypting and transmitting messages in extreme environments. This study highlights the strong potential of MOFs-reinforced organohydrogels for next-generation flexible electronic devices.