Balancing the Overall Performance of Poly(vinyl alcohol)/MXene Composite Organohydrogels for Flexible Strain Sensors

Solvent replacement is an effective strategy to improve the freezing resistance of hydrogels. The physicochemical properties of those organics are key to the overall performance of as-obtained organohydrogels. In this work, we performed a comparative study to explore the relationships between the types of solvents with similar chemical structures and the intrinsic properties of the organohydrogels. Poly(vinyl alcohol)/MXene composite hydrogel was used as a template, and three types of alcohols (ethanol, ethylene glycol, and glycerol) were used as exchange solvents. A “2-varible/5-outputs” method was developed, and the overall performance of as-obtained organohydrogels was optimized in terms of alcohol types and weight retention ratios. The organohydrogel containing ethanol with 50% weight retention ratio showed balanced properties: optimized modulus and good strength, superior compliance and recovery efficiency, high strain sensitivity, and wide detection range, which was more suitable to detect human motions. This work can provide valuable information on fabricating organohydrogels with optimized overall properties for flexible strain sensors.