Antifreeze Polyvinyl Alcohol Organohydrogel Sensors Containing Polypyrrole Nanowires Self-Assembled onto Graphene Oxide Nanoplatelets with High Electrical Conductivity and Improved Mechanical Properties

Conductive hydrogels exhibit significant potential for flexible electronics owing to their exceptional flexibility, resistance to deformation, and high conductivity. However, there is a critical need to develop hydrogels that can withstand extremely low temperatures while exhibiting good mechanical properties. In this study, carboxyl-modified polyvinyl alcohol (PVA) as the gel matrix, dimethylsulfoxide and water as a mixed solvent solution, and graphene oxide (GO) assembled polypyrrole (PPy) nanowires are used to prepare a new type of antifreeze conductive organohydrogel (PGOPPy). The PGOPPy organohydrogel demonstrates outstanding antifreeze properties, retaining its flexibility at temperatures as low as -75 degrees C. It exhibits a fracture strength of 0.80 MPa and an elongation at break of 436% at room temperature. Remarkably, after being stored at room temperature for 15 days, the diameter of the PGOPPy organohydrogel changes only by 4%. Moreover, PGOPPy shows high electrical conductivity, up to 1.07 S m-1, and exhibits variable conductivity in response to mechanical deformation, with a stable response over cyclic deformations, allowing its use as a sensor to monitor body movements. Results demonstrate that the developed material is very promising as an effective sensor technology for use in extremely cold environments. Moreover, this work provides a general method for preparing antifreeze organhydrogels using water and dimethylsulfoxide as mixed solvents. New organohydrogels based on polyvinyl alcohol/water/dimethylsulfoxide and containing polypyrrole nanowires-modified graphene oxide show antifreeze properties, retaining their flexibility at temperatures as low as -75 degrees C, and display high electrical conductivity and stable electrical response to cyclic deformation, allowing their application as movement sensors in extremely cold environments. image