Anti-Freezing and Anti-Drying Organohydrogel Coated with Graphene for Highly Sensitive and Ultrastretchable Strain Sensing

This work presents a new strategy to develop an ultra-stretchable and sensitive strain sensor based on dual network (DN) hydrogel with enhanced anti-freezing, anti-drying and strain sensing ability. The two polymer networks of this hydrogel consist of polyacrylamide (PAM) and carrageenan which can disperse the externally applied stress and maintain a certain morphology integrity when the hydrogel is deformed. Thanks to the reduced graphene oxide (rGO) coated on the surface of the DN hydrogel, the obtained hydrogel sample showed ultrahigh gauge factor (GF) as a strain sensor due to the tunneling effect which make the resistance of the sensor change much more than the pristine one when it detects strain. The GF of the obtained composite hydrogel-based strain sensor reached to 90.5 which is about 20 times higher than the sample without coating rGO in a large detection range from 1% to 400% strain. Furthermore, to endow this hydrogel with anti-freezing and non-drying ability, we soaked it into 1,2-Propanediol (PG) to replace some water molecules in it for a given time, which made it not freeze at −60°C and could keep water 3.6 times more than before in a dry environment, showing a broad application prospect in the field of strain sensing in harsh environments.