Assembling mixed carboxylic acid molecules on hierarchical structured aluminum substrates for the fabrication of superoleophobic surfaces with controlled oil adhesion

Controlling oil adhesion on the superoleophobic surfaces is very important in both fundamental research and practical applications. Herein, we report a new method through modification of mixed carboxylic acid (CH₃(CH₂)₆COOH and CF₃(CF₂)₆COOH) molecules on hierarchical structured aluminum substrates toward the fabrication of superoleophobic surfaces with tunable adhesion. The oil adhesion can be controlled by changing the concentration of CF₃(CF₂)₆COOH (x_F) in the modified solution. Detailed research indicates that the tunable effect is ascribed to the combined effect of the surface chemistry variation and the hierarchical structures on the substrates. Furthermore, we also demonstrate an application of our surfaces in a droplet-based microreactor. The results reported here can not only provide a new idea for fabrication of superoleophobic surfaces with tunable adhesion but can also potentially be used in many applications, such as microfluidic devices and chemical microreactors.