Fabrication of Superhydrophobic Surface on Anodized Aluminum Through a Wet-Chemical Route

Fabrication of superhydrophobic surfaces on anodized aluminum substrates by wet-chemical grafting using cost-effective chemicals through a simple immersion process is described in this work. Formation of formate-alumoxane is possible by treating the anodized and sealed aluminum substrate with formic acid at around 50 degrees C. On treatment with sodium salts of higher-order carboxylic acids (stearic acid, lauric acid, and palmitic acid), the formate ions are replaced by higher-order carboxylates. A possible bonding mechanism of the longer chain carboxylic acids with aluminium surfaces has been suggested based on IRRAS and XPS studies. The as-prepared superhydrophobic aluminum substrates exhibited a static water contact angle of up to 167 degrees with a sliding angle not higher than 6 degrees, with decent resistance against abrasion in addition to good UV, environmental and thermal stabilities. Aluminium substrates of any size, shape and surface finish can be easily rendered robust and superhydrophobic without the use of expensive chemicals and sophisticated machinery.

Automated summary

This work describes the fabrication of superhydrophobic surfaces on anodized aluminum substrates using cost-effective chemicals through a simple immersion process. By treating the anodized and sealed aluminum substrate with formic acid, formate-alumoxane can be formed. The formate ions are replaced by higher-order carboxylates through treatment with sodium salts of higher-order carboxylic acids. The as-prepared superhydrophobic aluminum substrates exhibit high water contact angle and low sliding angle, as well as good resistance against abrasion, UV, environmental and thermal stabilities. Without the use of expensive chemicals and sophisticated machinery, aluminum substrates of any size, shape and surface finish can be easily rendered robust and superhydrophobic.