Superoleophobic textured aluminum surfaces

With the aim of creating superoleophobic surfaces on engineering materials and understanding the influences of surface structures on the oleophobicity, we develop a convenient route to achieve superoleophobic surfaces on aluminum substrates using simple etching and surface fluorination. The liquid repellency of the textured surface is demonstrated by visible experimental results and contact angle measurements. Etching conditions, such as the etching time and etching procedure, play critical roles in establishing the oleophobicity. The micrometre-scale structures are essential for achieving the composite interface with low surface tension liquids, and the nanoscale structures formed in the treatment with boiling water lead to a decrease of contact angle hysteresis, bringing about an enhancement of superoleophobicity.