High-strength, anti-drying and freezing-resistant conductive hydrogels based on deep eutectic solvents

Conductive hydrogels demonstrate exceptional potential for applications in biosensors, bionic robotics, and intelligent sensing. However, conventional conductive hydrogels suffer from limitations including inadequate mechanical strength, low toughness, poor anti-drying and freezing resistant. To address these challenges, this work proposes a novel strategy to fabricate a high-strength, anti-drying, and freezing resistant hydrogel based on a deep eutectic solvent (DES) system, using liquid metal as the initiator and the crosslinker. First, Tween-20 was employed as an emulsifier to disperse liquid metal nanoparticles (LMNPs) in a choline chloride-glycerol deep eutectic solvent (DES) through high-speed homogenization. Subsequently, acrylic acid (AA) and acrylamide (AM) were introduced into the above emulsion. Then, a double-network Gel-LM-PVA-P(AA- co -AM) hydrogel crosslinked by liquid metal was formed via ultrasonication inducing LM-initiated radical polymerization. The resulting hydrogel exhibits outstanding mechanical properties and fatigue resistance with a fracture stress of 1.34 MPa, a fracture strain of 517%, a toughness of 5.68 MJ/m 3 , and a Young's modulus of 1.2 MPa. The introduction of DES endows the hydrogel with excellent anti-drying and freezing resistance. Furthermore, the hydrogel demonstrates remarkable antibacterial performance and favorable electrical conductivity (0.30 mS/cm) and remarkable strain-sensing capabilities, enabling rapid, sensitive, and stable responses to diverse human motions. Therefore, this work developed a new method for the preparation of high strength, anti-drying and freezing resistant conductive hydrogel, which demonstrating considerable potential in the field of flexible electronics and wearable devices.