Pullulan-mediated dynamic interfacial regulation for antifreezing conductive hydrogels with high toughness and low hysteresis.

Developing conductive hydrogels with both mechanical integrity and electrical functionality at subzero temperatures remains challenging. This is mainly due to the intrinsic trade-off between energy dissipation and structural stability. In this work, we report a multi-component conductive hydrogel based on poly(sodium acrylate-co-N-(2-hydroxyethyl)acrylamide), pullulan, glycerol, and liquid metal, in which the interplay between weak interfacial interactions and a dynamic polymer network is rationally regulated. The incorporation of pullulan modulates interfacial interactions in the hydrogel network and contributes to low hysteresis during cyclic deformation. Meanwhile, the copolymer network enables efficient stress transfer through chain entanglement, while dynamic interactions provide controlled energy dissipation under deformation, leading to a desirable balance between elasticity and toughness. Glycerol further enhances the anti-freezing capability by forming hydrogen bonds with water, thereby ensuring ionic mobility and mechanical compliance at low temperatures. As a result, the hydrogel exhibits high stretchability, outstanding toughness, low hysteresis, and high conductivity. Demonstrations of strain sensing for human motion monitoring confirm its potential in wearable electronics. This work offers a promising strategy for designing hydrogels with tailored mechanical and electrical properties for flexible electronics.