Antifreeze Liquid-Infused Surface with High Transparency, Low Ice Adhesion Strength, and Antifrosting Properties Fabricated through a Spray Layer-by-Layer Method

As frost formation and ice accumulation result in serious problems in various industrial systems, some anti-icing system is highly required, and passive anti-icing processes based on ice prevention coatings have attracted much attention, Recently, antifreeze liquid-infused surfaces (LISs) have been developed for the preparation of ice-phobic surfaces owing to their low ice adhesion strength and antifrosting properties. However, it is still challenging to add an optical function such as high transparency to antifreeze LISs despite the potential for the application in window coatings. In addition, the influence on anti-icing properties by the thickness of antifreeze liquid layer and base layer are still unclear. Here, we designed highly transparent coating surfaces that were resistant to ice adhesion and frost formation. We controlled the thickness, surface roughness, and refractive index of the base layer through a spray layer-by-layer (LbL) method and then investigated the effect on the optical properties, ice adhesion strength, and frost formation behavior. The frost-resisting properties of the surfaces were clearly improved with the increase of the lubricant thickness as well as the increase of the number of bilayers; the parallel transmittance of antifreeze US composed of ethylene glycol and this base layer was approximately 92.6%, and the ice adhesion strength was below 17 kPa regardless of the number of bilayers. These results indicated that a high lubricant thickness coating can achieve both excellent anti-icing properties and transparency; the antifreeze LIS based on a 100 bilayer base coating had excellent antifrosting properties owing to its thick antifreeze liquid layer and maintained both of high transparency and low ice adhesion. Furthermore, the spray LbL method makes it possible to fabricate the base layer in short time and also in large scale, which is quite useful for the practical application of antifreeze US. This work will be of enormous help for the design of transparent anti icing coatings as well as industrial applications such as solar cells and the windows of transportation vehicles.