Fluorine-free superhydrophobic surface with micron-nanosized two-tiered structure for self-cleaning, anti-frosting, and anti-icing applications

Superhydrophobic surfaces with micron-nanosized two-tiered structures have huge potential in practical applications. However, the complex preparation process and low-stability of the versatile superhydrophobic surfaces restricted their wide application. Herein, a facile chemical etching process was applied to create a micron-sized rough structure on the 1060 aluminum alloy substrate, and the micron-sized rough structure surface (M-surface) was hydrophobic with a water contact angle of 113.50° ± 2.7°. Then, the M-surface was modified by hydrophobic SiO2 nanoparticles, and a superhydrophobic micron-nanosized two-tiered structure surface (MNSS-TMES/H-SiO2 coating) with a water contact angle of 161.20° ± 2.3° was constructed. The as-prepared MNSS-TMES/H-SiO2 coating can maintain superhydrophobicity after self-cleaning, sand impact, and anti-frosting tests. More importantly, the MNSS-TMES/H-SiO2 coating exhibited superior anti-icing performance and higher defrosting efficiency. The freezing delay time of a water droplet on the MNSS-TMES/H-SiO2 coating was prolonged to 4973.87 s at − 15 °C, and the frost layer on the resultant coating was melting speedily and turned into several isolated spherical water droplets in approximately 20 s. Therefore, the prepared durable fluorine-free superhydrophobic MNSS-TMES/H-SiO2 coating with self-cleaning performance, higher defrosting efficiency, and the ability to delay icing, which has great prospects in practical applications.