Trehalose-toughened transparent hydrogel with fast-healing and anti-freezing capability for precision human motion detection

Conductive hydrogels have garnered extensive attention in flexible sensing technologies due to their unique combination of mechanical compliance and electrical conductivity. However, conventional systems face a critical limitation that the inability to synergistically integrate optical transparency, balanced mechanical/electrical properties, fast self-recovery, and anti-freezing property, thereby constraining their advanced applications. This study explores a facile “one-step” strategy to engineer a poly (acrylic acid)-Zr 4+ /trehalose hydrogel, where biologically derived trehalose serves dual roles as both a cryoprotectant (enabling -45 °C operability) and mechanical toughener. The Zr 4+ -enabled ionic coordination network simultaneously establishes a stiff structured matrix, yielding multifunctionality such as high transparency (up to 92 %), robust mechanical performance (2.86 MPa tensile strength, 1542 % strain, 11.2 MJ/m 3 toughness), high ionic conductivity (32.1 mS/cm), and rapid autonomous recovery (99.6 % efficiency within 10 min). Notably, we developed an innovative ultrafast healing mechanism achieving 79.2 % healing efficiency in just 1 min, overcoming the time-dependent limitations of conventional dynamic networks, ensuring durability under cyclic mechanical stress. This systemic integration of previously incompatible properties positions the hydrogel as a candidate for multifunctional flexible sensors, particularly in extreme environments where traditional systems fail. Its high ionic conductivity and subzero resilience enable reliable sensing in extreme environments, while sensitive strain/pressure detection ensures precise monitoring of subtle motions. The synergy between anti-freezing capability of trehalose and dynamic network of zirconium addresses critical challenges in wearable sensors, combining durability, environmental adaptability, and signal fidelity.