Bioinspired Anti-Icing Hydrogel Enabled by Ice-Nucleating Protein

Ice-nucleating proteins (INPs) are the most effective ice-nucleating agents that play a significant role in preventing freeze injuries in freeze-tolerant organisms. INPs promote ice nucleation in the extracellular space, harvesting water from cells due to the low vapor pressure of ice compared with water, thereby protecting freeze-tolerant organisms from intracellular freezing. The antifreeze mechanism of INPs offers a unique opportunity to inhibit large-scale freezing by localized control of ice formation, with valuable enlightenment in anti-icing material sciences. By learning from nature, we transferred the excellent ice nucleation-facilitating capability of INPs along with an antifreeze concept of spatially controlled ice nucleation to anti-icing material design, fabricating icephobic coatings that consisted of patterned hydrogel-encapsulated INP (PHINP). The ice patterns were templated by patterned PHINPs via the tuning of ice nucleation so that the ice coverage fraction could be controlled by <30% on almost all PHINP-coated surfaces. Combining PHINP with solar-thermal conversion surfaces endowed the composite coatings with high anti-icing performances at any time of the day.