Anti-freezing Dough for Renewable and Reconfigurable Flexible Strain Sensors

With the rapid development of the Internet of Things technology, flexible strain sensors that facilitate bidirectional communication between humans and machines will play an important role. On the one hand, flexible strain sensing methods focusing on nonbiodegradable or nonrenewable materials face recycling challenges, and resource waste and environmental pollution issues. On the other hand, biocompatible flexible sensors are mostly ion-conducting and face low-temperature challenges. In this study, dough materials with anti-freezing and self-repair capabilities were rapidly prepared from traditional flour at room temperature using a solvent mixture of H₂O/ethylene glycol (EG) as an antifreeze agent and NaCl as a conductive agent. Owing to the hydrogen bonding network formed by the proteins, the doughy soft material exhibited good mechanical properties. The free ions provided by NaCl enabled the doughy material to exhibit high ionic conductivity. After being assembled into a capacitive-based flexible strain sensor, the sensor exhibited good detection sensitivity (GF = 1.61%) and good application potential in joint motion monitoring. In addition, the flexible sensor maintains good sensing performance at −20°C due to the frost resistance provided by the EG.