Magnetic responsive and flexible composite superhydrophobic photothermal film for passive anti-icing/active deicing

The formation and accumulation of ice can lead to severe economic loss or even loss of life. To prevent these losses, there has been rapid development in icephobic materials in recent years. To deal with various icing conditions and different types of components, it is highly desirable to develop a surface that possesses both passive anti-icing and active deicing functions. However, so far there is no suitable solution for anti-icing material with adequate durability, low cost, and simplicity in fabrication that can also be turned into active deicing when necessary. Here, we demonstrate a magnetically responsive and flexible superhydrophobic photothermal film (PFe-PCS) consisting of polydimethylsiloxane (PDMS), iron powder (Fe), and candle soot (CS). The film displayed both passive anti-icing and active deicing performances by a simple approach without using fluorine-containing chemicals. The film consists of two superhydrophobic layers that can trap two air layers in the micro/nano structures. As a result, the freezing time is 4.7 times of that of bare substrate. Such designed surface structure not only displays a significant delay in water freezing time, but also minimizes heat loss by keeping the heat within the top surface during photothermal heating. The accumulated ice can be immediately melted in 237 s and the melted water can be rapidly rolled off. The PFe-PCS film can be applied to substrates with complex shapes including curved substrates via magnetic force. More importantly, the PFe-PCS film displayed excellent stability when exposed to strong acid, base, salt solutions and liquid nitrogen. The superhydrophobicity and anti-icing performances were well retained after 320 cycles sandpaper abrasion, 3 h water flow impact, and cyclic icing/deicing. This work originated the concept of double layered surface structure for both passive anti-icing and active de-icing. The film is robust and self-healing, making it potentially applicable for ice prevention and removal for various shaped components.