Strong and tough anisotropic short-chain chitosan-based hydrogels with optimized sensing properties for flexible strain sensors

Conductive hydrogels are ideal candidates for developing flexible electronic devices, but they still cannot exhibit excellent strength, satisfactory toughness and high conductivity in sync, greatly limiting their further applications. Inspired by the structure-enhanced properties of natural tissues, we adopted a straightforward and efficient methodology for constructing strong and tough anisotropic short-chain chitosan-based hydrogels with salting-assisted tensile remodeling treatment. The anisotropic hydrogels present anisotropic mechanical and electrochemical performance due to the oriented arrangement of chitosan and P(AM-AA) macromolecular networks. The remarkable tensile strength, toughness, and conductivity of parallel-oriented hydrogels are up to 9.01 MPa, 32.77 MJ/m³, and 692.30 mS/m, respectively, which are much higher than that of isotropic and vertical-oriented hydrogels, verifying the structure-optimized mechanical and sensing performance. The anisotropic conductive polypolysaccharide hydrogels are assembled as strain sensors for real-time human movement monitoring, Morse code encryption and decryption transmission, and gesture prediction combined with a machine learning algorithm, providing new inspiration for blossoming strong, flexible electronic products.