Anisotropic conductive eutectogels for strain sensing and triboelectric nanogeneration in extreme environments

Conductive hydrogels have attracted widespread attention for their promising application prospects in portable and flexible electronic devices. However, hydrogels commonly suffer from problems such as solvent volatilization and freezing at low temperatures. Inspired by tissues such as human muscles, tendons, and ligaments, this study proposes a facile method to produce anisotropic conductive strong and tough eutectogels through directional freezing integrated with solvent substitution (DFSS) strategy. Eutectogels with anisotropic characteristics exhibit a highly anisotropic structure, conferring distinctive anisotropic mechanical properties and electrical conductivity. The prepared anisotropic PVA-M-DES eutectogels exhibit excellent mechanical properties (high strength of 6.31 MPa, high toughness of 20.75 MJ m^-3, elastic modulus of 2.36 MPa, and fracture strain of 596%), high conductivity (0.17 S m^-1), excellent anti-freezing and anti-drying properties. Environment-tolerant anisotropic PVA-M-DES eutectogels can be assembled into strain sensor and triboelectric nanogenerator to achieve real-time monitoring of various human motions and have potential applications in wearable electronics, personal healthcare, energy harvesting, and human-machine interfaces.