Anisotropic double-network hydrogels integrated superior performance of strength, toughness and conductivity for flexible multi-functional sensors

Conductive hydrogels have attracted extensive attention in the field of flexible electronics due to its inherent outstanding properties. However, how to solve the contradictory relationship among conductivity, strength and toughness of hydrogel was still a huge challenge. Inspired by the muscle architecture, an anisotropic cellulose nanofiber (CNF) based double-network conductive hydrogel containing oriented MXenes was successfully fabricated, in which the asymmetric double network structure contributed to excellent strength and toughness, while the conductivity of the hydrogel was enhanced by the ion nanochannels derived from aligned MXenes. Consequently, the resulting hydrogel integrated superior performance of strength, toughness and conductivity, which were 3.33 MPa, 1106 % and 13.08 S/m respectively, surpassing the most reported hydrogels. Profiting from the superior conductivity and mechanical performance, the anisotropic hydrogel could be assembled into multi-functional flexible electronics, such as a flexible touch panel, a flexible strain/pressure sensor with high sensitivity and stability. Together with the superior compatibility for human–computer interaction, the obtained hydrogel wearable sensor showed a promising application potential for the real-time wireless monitoring of human motion and the real-time control of a robot.