Transparent Anti‐Icing Coating via Synergistic Nanoscale Interfacial Engineering and Spectral‐Selective Photothermy

Abstract Passive anti‐icing should have been an idea strategy to prevent ice accumulation on cold surface, yet often proves unsatisfactory or even counterproductive in effect due to the fundamental challenge of overcoming the thermodynamic driving force for ice nucleation during temperature decreasing and the empirical nature of conventional design approaches. While photothermy offers a cost‐effective and eco‐friendly active anti‐icing solution, currently used photothermal materials face a trade‐off between efficiency promotion and transparency maintenance stemming from their broadband‐solar absorption characteristics. Here, a hierarchical anti‐icing system is developed combining: 1) an unconventional and foolproof passive strategy that elevates the threshold of thermodynamic driving force required by ice nucleation, i.e., ice nucleation free energy barrier, through nanoscale (critical ice nucleus dimensions) interfacial engineering, and 2) an active photothermal strategy that employs spectral‐selective materials with visible‐light transparency. This synergistic strategy enables water on the engineered transparent coatings to remain unfrozen for at least 1 h without solar illumination and enduringly unfrozen under irradiator, at temperature conservatively down to −25 °C and aggressively down to −30 °C. The simple, effective, universal method is promising to bring superior transparent anti‐icing coatings by further reducing the scale for interfacial engineering and optimizing material types.