Bio-inspired superoleophobic fluorinated wax crystalline surfaces

A novel, single-step and single-component bio-inspired fabrication method of hierarchical superoleophobic surfaces is presented. The method consists in thermal deposition of self-assembling ultra-low-surface-energy fluorinated wax on diverse surfaces. The thermal deposition results in crystalline, oriented, three-dimensional hierarchical structures with high surface roughness and re-entrant curvature, which in combination with the low surface energy of the fluorinated wax results in high contact angles of low-surface-tension liquids and low contact-angle hysteresis (CAH) values (Δθ). The values achieved for Δθ are below 10° even for ethanol, which exhibits a surface tension as low as 22.4 mN·m^-1. In addition to their superoleophobic properties our substrates exhibit extreme superhydrophobic qualities (CAH as low as 2° and contact angle >170°) with exceptional surface stability over many months. The proposed fabrication method may be utilized for a variety of applications where non-wetting of low-surface-tension liquids is required, for example non-staining surfaces and antifouling. The ease of fabrication and the variety of substrates that can be modified will undoubtedly widen its use.