No abstract

Traditional anti-icing strategies, including mechanical, electrothermal, and chemical deicing, are commonly used on outdoor infrastructures and transportations. [7] However, these methods are inefficient, energy-consuming, and/or unfriendly to the environment. [8] More efficient and environment-friendly antiicing coatings can inhibit ice nucleation and decrease ice adhesion without human intervention, having attracted more attention in recent years. [9] Up to date, there have been many types of advanced antiicing coatings including superhydrophobic surfaces, [10,11] slippery liquid-infused porous surfaces, [12,13] and other ice-phobic surfaces. [14][15][16] They have presented high efficiency to prevent icing based on different mechanisms. However, artificial surface-based coatings are commonly difficult to work well in outdoor environments, especially in extreme weather events (such as freezing weather or acid rain). Once mechanical damage induced by surroundings or icing/deicing cycles on coating surface, ice nucleation and ice-substrate interlocking would be evoked, resulting in icing promotion and stronger ice adhesion. Therefore, it is highly desired to develop an anti-icing coating that possesses excellent durability in resistance to universal conditions.Inspired by biological tissues, self-healing materials can be employed to enhance durability in a variety of applications such as flexible electronics and energy storage devices. [17,18] Self-healing ability can repair potential defects to avoid frequent maintenance of devices and significantly prolong the service lifetime. It can thus be proposed that autonomously self-healing anti-icing coatings can effectively inhibit defect-induced icing and ensure coating durability. [19,20] However, there are few reports with respect to autonomously self-healing anti-icing under extreme conditions. The challenge is mainly owing to two aspects: 1) There is a tradeoff between anti-icing performance and self-healing property. Because self-healing commonly relies on dynamic bonding interactions (such as dynamic H-bonds) that can promote ice adhesion on the material surface. [21,22] 2) Underwater or in freezing conditions, the healing efficiency of materials would be significantly decreased because the dynamic bond reconnection would be inhibited by water molecules, and the mobility of polymer chains is decreased in low temperature to prevent healing. [23] Anti-icing coatings on outdoor infrastructures and transportations inevitably suffer from surface injuries, especially in extreme weather events (e.g., freezing weather or acid rain). The coating surface damage can result in anti-icing performance loss or even icing promotion. The development of anti-icing coatings that enables self-healing in extreme conditions is highly desired but still challenging. Herein, an extreme-environment-resistant selfhealing anti-icing coating is developed by integrating fluorinated graphene (FG) into a supramolecular polymeric matrix. The coating exhibits both antiicing and deicing performa...

Anti-icing coatings on outdoor infrastructures inevitably suffer from mechanical injuries in numerous icing scenarios such as hailstorms, sandstorms, impacts of foreign objects, and icing–deicing cycles. Herein, the mechanisms of surface-defect-induced icing are clarified. At the defects, water molecules exhibit stronger adsorption and the heat transfer rate increases, accelerating the condensation of water vapor as well as ice nucleation and propagation. Moreover, the ice–defect interlocking structure increases the ice adhesion strength. Thus, a self-healing (at −20 °C) antifreeze-protein (AFP)-inspired anti-icing coating is developed. The coating is based on a design that mimics the ice-binding and non-ice-binding sites in AFPs. It enables the coating to markedly inhibit ice nucleation (nucleation temperature < −29.4 °C), prevent ice propagation (propagation rate < 0.00048 cm 2 /s), and reduce ice adhesion on the surface (adhesion strength < 38.9 kPa). More importantly, the coating can also autonomously self-heal at −20 °C, as a result of multiple dynamic bonds in its structure, to inhibit defect-induced icing processes. The healed coating sustains high anti-icing and deicing performance even under various extreme conditions. This work reveals the in-depth mechanism of defect-induced ice formation as well as adhesion, and proposes a self-healing anti-icing coating for outdoor infrastructures.