Evaluation of Long-Term Stability and Performances of Eco-Friendly and Low-Power Temperature Sensor Based on Hydrogel Nanocomposite

A low-cost nanocomposite material, comprising gelatin and graphene, has been used to fabricate an environmentally friendly temperature sensor. Operating within a temperature range of 260 to 310 K, the sensor maintained a consistent sensitivity of approximately −19 mV/K over two years. Additionally, it demonstrated the capability to detect ice formation at sub-zero temperatures. Experimental evidence indicates that aged sensors can be regenerated by water uptake at a temperature exceeding the gelation point of the hydrogel nanocomposite. After the hydration procedure, the aged sensor displays improved conductivity and partially restores its performance. Both in its pristine and aged states, the electrochemical sensor shows a fast response time and low power consumption within the micro-watt range. Its regenerative potential offers sustainability and reusability benefits for temperature monitoring and environmental sensing.