Highly durable spray-coated superhydrophobic surface: Pre-anodizing and fatty acid chain length effect

Abstract

In the study, aluminum plates were first anodized and then coated with ZnO by spray-pyrolysis method. By modification with long chain fatty acid, these surfaces demonstrate superior hydrophobicity and durability. After optimizing the anodizing time for each fatty acid, several runs were conducted by varying concentration and spray solution quantity. Comparison was made by optimizing the process parameters in which each acid showed maximum hydrophobicity. Anodized, spray coated and modified surfaces were characterized by FT-IR, XRD, SEM and topography analysis. The chemical and mechanical strength of the surfaces were explored under various extreme conditions. The highest contact angle of 164 degrees was obtained by coating 10 minutes anodized surface with 0.4 M and 15 ml ZnNO3 solution and modifying it with stearic acid. In the performed tests, it has been observed that this surface is much more durable than surfaces modified with other fatty acids.