Hydroxypropyl methylcellulose-reinforced metal-ligand coordination-entanglement eutectogels for highly sensitive,
Yapeng Zheng1, Jing Wang1, Tianyang Cui1
1State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, 230026, PR China.
Abstract:
Accurate detection and efficient transduction of thermal stimuli across biological, environmental, and electronic settings are essential for flexible temperature sensors that underpin electronic skin, human-machine interfaces, and hazard monitoring. Yet, flexible sensors still face inherent trade-offs between sensitivity, operating range, and stability. Established strategies-hydrogels (dehydration/icing), ionogels (ion leakage/structural degradation), and conductive filler/elastomer composites (rigidity-flexibility compromise)-remain constrained. Here, a metal-ligand coordination-entanglement co-driven strategy is implemented within a tailored solvent framework comprising deep eutectic and polymerizable solvent systems to form P(AA-co-AAM)/LiTFSI/ZnCl2-EG/hydroxypropyl methylcellulose (HPMC) eutectogels. Physical entanglement of HPMC coupled with metal-ion coordination creates reconfigurable ion-transport pathways and programmable mechanical networks, enabling high-sensitivity and robust temperature sensing. The resulting eutectogel-based flexible temperature sensor demonstrates high sensitivity (temperature coefficient of resistance, TCR = -12.86% °C-1), a fine temperature resolution of 0.10 °C, excellent linearity (R2 = 0.990), and stable operation across 6-90 °C. Relative to state-of-the-art flexible sensors-including hydrogels, ionogels, elastomers, and electronic conductors-the eutectogel sensor delivers a high B value (~4840 K), high TCR, fine resolution, strong linearity, and a broad operating window. Together, these findings identify metal coordination-entanglement co-driven eutectogels as ideal sensing platforms that couple exceptional sensitivity with broad operational adaptability.
