Hydrogel-based temperature sensor with water retention, frost resistance and remoldability

Conventional hydrogels will be frozen at low temperatures and lose their flexibility. At higher temperatures, hydrogels will lose water more quickly. The inherent property of hydrogels hinders its development in the field of flexible wearable sensors. In this research, we studied the anti-freezing and moisturizing mechanism of glycerol (Gly), ethylene glycol (EG) and CaCl2 aqueous solutions. The Gly solution with excellent antifreeze humectant and friendly to the organism was selected as antifreeze humectant. We introduced Gly into PVA gel to make the gel have anti-freezing and moisturizing properties, and then introduced silver nanofibers (AgNW) into the gel to obtain the temperature sensor with anti-freezing and moisturizing properties. Since the gel uses reversible physical cross-linking, the sensor has excellent remodeling ability. The temperature sensor has the advantages of high sensitivity, short response time to temperature and excellent accuracy. It is expected to be applied to temperature sensors under severe weather conditions.