Cryo-healing anti-icing zwitterionic hydrogels

The functional failure of anti-icing surfaces under mechanical damages in frigid environments is a critical, yet unsolved, challenge, as conventional self-healing mechanisms are inoperative by freezing. Here, we report a Cryo-Gel material, which autonomously repairs damage at −20 °C, driven solely by fluidic water molecules. This material is a zwitterionic hydrogel network integrating dynamic non-covalent borate esters within a covalent framework. It achieves a synergistic mechanical robustness and rapid bond reconfiguration at subzero temperatures, enabling water-triggered self-healing upon rinsing, defrosting, or rainfall. A single defrosting cycle is sufficient to heal the abraded Cryo-Gel and restore its exceptional anti-icing properties. At an extreme −45 °C, the Cryo-Gel delays frost formation by 20-fold and ice accretion by 2.5-fold compared to an uncoated surface. This work establishes a new principle for creating durable, adaptive ice-phobic materials capable of withstanding extreme conditions, overcoming the fundamental kinetic limitations that have plagued previous self-healing systems.