Conductive
hydrogels have attracted intensive attention for versatile functions in flexible electronics because of their unique combination of mechanical flexibility and conductivity. However,
hydrogels containing plenty of water inevitably freeze at subzero temperature, leading to invalid electronics with failed mechanical advantages and negligible conductivity. Moreover, the inferior elasticity and
fatigue resistance of
hydrogels result in unstable sensing performance and poor reusability of
hydrogel-based electronics. Herein, a freezing-tolerant, high-sensitive, durable strain and pressure sensor was constructed from an ionic conductive
chitosan-
poly(acrylamide-co-acrylic acid) double-network [CS-P(AM-co-AA) DN]
hydrogel with dual-dynamic cross-links (
chitosan physical network and ionic coordination [CO2LFeIII]), which was feasibly fabricated by soaking the CS-P(AM-co-AA) composite
hydrogel in FeCl3
solution. The
ions immobilized in dynamic cross-links exerted crucial effects on improving mechanics [prominent tensile performance, supercompressibility, extraordinary elasticity, fast self-recovery capacity, and remarkable
fatigue resistance (1000 cycles)]; meanwhile, the free
ions in the
hydrogel rendered the
hydrogel excellent conductivity and strong freezing tolerance concurrently. The sensor assembled from the DN
hydrogel exhibited cycling stability and good durability in detecting pressure, various deformations (elongation, compression, and bend), and human motions even at a low temperature (-20 °C). Notably, the sensitivity on detecting strain and pressure at both room and subzero temperature was superior than most of the reported organohydrogel and
hydrogel sensors. Thus, we believe that this work will provide a platform for construction and application of high-sensitive strain and pressure
hydrogel sensors with cycling stability and good durability in a wide temperature range.