Thermal responsive sodium alginate/polyacrylamide/poly (N-isopropylacrylamide) ionic hydrogel composite via seeding calcium carbonate microparticles for the engineering of ultrasensitive wearable sensors

The design of polyelectrolyte hydrogel with unique tensile and adhesive properties which can be applied across disciplines has gradually become a popular trend. However, the phenomenon of global warming and the emergence of extreme weather, it still faces some urgent problems that should be solved, such as the optimal utilization of polyelectrolyte hydrogel across a wide range of temperatures. Herein, a wide temperature sensitivity and conductivity hydrogel based on sodium alginate, acrylamide and N-isopropylacrylamide was constructed, which exhibited excellent adhesion and temperature conductivity. It is worth noting that after the inclusion of CaCO 3 and NaCl in the hydrogel, the hydrogel showed excellent tensile properties (fracture strain >2000 %). Within a wide temperature range (−15–50 °C), it exhibits exceptional electrical conductivity (2.75 S ∗ m −1 ) and sensitivity (GF = 8.76 under high strain). This innovative intelligent polyelectrolyte hydrogel provides suitable strategy for flexible sensors, smart wearable devices and medical monitoring equipment.