Cryo-healing anti-icing zwitterionic hydrogels

Cryo-Gel autonomously self-heals mechanical damage at −20 °C using only fluidic water molecules without external stimuli. • Cryo-Gel delays frost formation by 20-fold and ice accretion by 2.5-fold compared to uncoated surfaces at −45 °C. • Self-healing arises from reversible borate ester bonds, hydrogen bonds, and electrostatic interactions. • The coating restores transparency and anti-icing function after 350-μm scratches and 1,000 Taber abrasion cycles. • Global energy modeling predicts a net annual gain of 1.833 TWh if the Cryo-Gels are applied in frost-prone regions. 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. Zwitterionic Cryo-Gels incorporate sulfobetaine methacrylate and 2-hydroxyethyl methacrylate through borate ester crosslinks. 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, overcoming traditional self-healing coatings' low-temperature failure limitations. Download: Download high-res image (142KB) Download: Download full-size image