Ever since Wenzel and Cassie-Baxter announced their theories with respect to wettability transition with surface roughness, numerous studies on fabricating superhydrophobic surface have been carried out to provide industries with the advantages of the superhydrophobic surfaces such as anti-frosting, water proof, and self-cleaning. In metal industries, several methods have been developed to achieve superhydrophobic surfaces on various metals, including aluminum, copper, and steel. However, the fabricated surfaces only show over 150 of contact angles (CAs) for water (surface tension = 72.0 mN/m at 25 ℃) and do not show excellent repellency to low surface tension oils.In the past few years, advantages of superomniphobic surfaces have been identified and many efforts are directed toward their practical industrial applications. Superomniphobic surfaces, unlike the superhydrophobic surfaces, show high repellency to low surface tension oils as well as anti-fouling, oil transfer, and oil-water separation properties. A superomniphobic surface is required to have not only a low surface energy but also a specific surface structure, because of which, it is much more difficult to fabricate than a typical superhydrophobic surface. Although a few fabrications of superomniphobic surface on titanium alloy (TiAl6V4) substrates have been reported, they are not superomniphobic to low surface tension oils like hexadecane, or are too far from industrialization because their fabrication relies on difficult methods such as laser micromachining. Further, there has been no report on achieving superomniphobic TiAl6V4 surfaces for hexadecane (surface tension = 27.1 mN/m at 25℃) using a simple method.In this study, we render TiAl6V4 substrates superomniphobic by acid etching followed by anodization. Each process is analyzed with respect to processing times for obtaining optimal hierarchical microhorn/nanopore structures. The surface structures were then fluorinated by a self-assembled monolayer (SAM) coating, thereby imparting great repellency to low surface tension oils, including hexadecane. The surface morphology of TiAl6V4 in each process and analyses of the surface chemical change are discussed. Figure 1
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