Superhydrophobic anti-icing/de-icing SR/CNTs surfaces hot-embossed with femtosecond laser machined mold

Abstract

Anti-icing/de-icing surfaces are dispensable in reducing accidents and economic losses caused by accumulated ice and frost on outdoor facilities in cold and humid environments. In this work, a low-cost, reproducible process was presented to fabricate superhydrophobic anti-icing/de-icing surfaces. For this purpose, concave micro-structures were firstly created on the mold steel surface using femtosecond laser machining, and then the corresponding convex micro-structures were prepared on the surface of a silicone rubber (SR) composite mixed with multi-wall carbon nanotubes (CNTs) using hot embossing. Thanks to the presence of unique micro-scale peak-ridge structures, the as-prepared SR/CNTs surfaces possess superhydrophobic characteristic. Long icing delay time was endowed by the large volume of air pockets inside micro-structures, and the icing time was significantly extended from 67 to 416 s, which is ascribed to the greatly inhibited heat transfer between the droplet and the surface. Moreover, the SR/CNTs surface had excellent photothermal conversion capability with the presence of photothermal particles CNTs, and the temperature of the surface increased rapidly from 21.6 to 86.1 °C in 5 min under a standard sunlight irradiation. In addition, the SR/CNTs surface also possesses superior photothermal defrosting and de-icing performance as the ice and frost on the surface can be quickly melted under a standard sunlight intensity irradiation and the de-icing rate is up to 0.92 mg/s. Finally, the good reusability of the mold steel and the resistance to mechanical wear and chemical corrosion of superhydrophobic SR/CNTs surface found in this work make the proposed approach promising for industrial mass production and anti-icing/de-icing applications in harsh environments.