Dual Conductive Network Hydrogel for a Highly Conductive, Self-Healing, Anti-Freezing, and Non-Drying Strain Sensor

Self-healing hydrogel plays an important role in flexible sensors. However, the development of high-performance hydrogel-based strain sensors with both high sensitivity and large sensing range remains a key challenge. Herein, we prepare a dual conductive network (DCN) hydrogel based on carbon nanotube (CNT) film and conductive hydrogel that exhibits high-conductivity, self-healing, anti-freezing, and non-drying features. The tolerance of this hydrogel to extreme temperatures is improved via a simple solvent replacement, enabling the DCN hydrogel to maintain high flexibility and stretchability under arduous conditions such as temperatures ranging from −85 to 50 °C. Additionally, owing to the dual conductive percolation network structure, the strain sensor based on DCN hydrogel exhibits a gauge factor as high as 343 at a strain of 110%, indicating high sensitivity. The mechanical and electrical performances of the hydrogel would be efficiently self-repaired after a simple heating–cooling treatment. The self-healing sensor can be mounted on the human body to detect biosignals in real time. Our work shows a method of fabricating high-performance self-healing hydrogel for future flexible electronics.