A composite pore-structured superhydrophobic aluminum surface for durable anti-icing

Abstract

The icing of overhead aluminum conductors is a serious threat to the safe operation of power systems. Various coatings for anti-icing have to face the challenge of durability. Superhydrophobic (SHP) coatings with self-healing properties are gradually showing good anti-icing durability. Herein, SHP self-healing surfaces with composite pore structures were successfully constructed on 1060 aluminum by two-step anodizing and infusion of triethoxy (1H,1H,2H, 2H-perfluoro-1-octyl)silane (POTS). A preparation process of composite pore structure consisting of upper layer of large pores and lower layer of small pores was designed and obtained via two-step anodizing. The impregnated POTS modified the composite pore structure to achieve superhydrophobicity while providing self-healing properties. The SHP surfaces with excellent performance were prepared by optimizing the appropriate current density and oxidation time. The contact and sliding angles were 166.5° and 0.5°, respectively. The frosting time was extended to 175 min, whereas the ice adhesion strength was lowered to 4.3 kPa. Additionally, the SHP surface with composite pore structure demonstrated superior durability and self-healing properties to single pore structure. The composite pore structure could maintain outstanding superhydrophobicity after 12 times of damage/self-healing compared to single pore structure (eight times). The SHP surface with composite pore structure successfully self-healed three times and withstood 135 icing/deicing cycles keeping the ice adhesion strength below 20 kPa, which is preferable to single pore structure (two times). The SHP self-healing aluminum surfaces developed in this work are highly promising for application and can promote the development of SHP coatings for anti-icing on power transmission lines.