Ultrasensitive flexible eutectogel sensor mediated by dynamic metal-ion coordination for safe and reliable cold-chain temperature monitoring

Flexible temperature sensors that can detect and transmit subtle thermal fluctuations are essential for critical cold-chain monitoring and safety assurance. However, realizing intrinsically soft materials with high temperature sensitivity and durability remains challenging. Prevailing approaches embed rigid thermoresponsive fillers into compliant matrices, resulting in limited sensitivity, poor long-term stability, and inadequate scalability under demanding cold-chain conditions. Herein, we report a coordination-driven design strategy leveraging metal-ligand dynamics within tailored polymerizable and deep eutectic solvent systems to construct P(N,N-dimethylacrylamide-co-vinylphosphonic acid)/Lithium bis(trifluoromethanesulphonyl)imide/ZnCl 2 /glycerol eutectogels. The resulting flexible eutectogel-based temperature sensor exhibits an ultrahigh thermal sensitivity (temperature coefficient of resistance: −28.43%°C −1 ), an ultrafine temperature resolution (0.10°C), excellent linearity ( R 2  = 0.989), and robust stability (> 30000 s) across a broad operational range (−5 to 100°C). These characteristics enable precise detection and early warning of abnormal temperature excursions pertinent to cold-chain safety. Furthermore, an integrated intelligent monitoring module supports real-time multi-threshold warning capabilities throughout the cold supply chain. Collectively, this work establishes dynamic metal-ion coordination-engineered eutectogels as a generalizable and flexible platform dedicated to high-resolution, ultrasensitive temperature sensing, early warning, and safety management in cold-chain logistics.