Robust Super-Amphiphobic Titanium Surface for Liquid/Liquid Mini Separations

Super-amphiphobic surface with low robustness is not suitable for practical application due to its weak mechanical strength. In this work, an in-site growth of micro-/nanoscale flower-like TiO2 on the surface of a titanium mesh was successfully fabricated through hydrothermal synthesis, followed by chemical modification with low-surface-energy heptadecafluoro-1,1,2,2-tetrahydrodecyl trichlorosilane. The resultant super-amphiphobic coating was highly repellent to all of the ethanol–water mixtures with surface tensions ranging over 26.0–72.8 mN/m, as well as excellent chemical and mechanical durability. After it was irradiated for 8 h with ultraviolet light, it was used for oil/water and oil/oil mini-separation with the help of its Janus characteristic. This was attributed to its unidirectional penetration for liquid droplets with different surface tension values. This kind of smart super-amphiphobic mesh with photochemical activity could potentially gate and sort liquids via surface tensions.