High Sensitive Nitrogen Dioxide Sensor Based on Polyvinyl Alcohol-Cellulose Nanofibril Organohydrogel with Repairability, Anti-Freezing, Stretchability, Long-Lasting Moisture, and High Strength

Fabrication of stretchable sensor has been increasingly attractive for emerging wearable applications in health assessment, internet-of-things, electronic skin, robotics, and environment monitoring. Nitrogen dioxide (NO
2
) is one of the most harmful gases to the human body and environment. Here, we demonstrate a novel high-sensitivity (233%/ppm) NO
2
gas sensor based on polyvinyl alcohol (PV A)-cellulose nanofibril (CNF) organohydrogel. This organohydrogel exhibits remarkable stretchability (break strain 672%), and high mechanical strength (up to more than 370 KPa). Besides, the PVA-CNF organohydrogels remained in their original condition without any damage on the surface after stretching 15 times. Basing on the crosslinked hydrogen bond, this PV A-CNF organohydrogel exhibits repairability and remoldability. The addition of glycerol increases the antifreezing ability and long-lasting moisture.