Using an "underwater superoleophobic pattern" to make a liquid lens array

This paper reports a new strategy to realize real liquid lens arrays without evaporation problems based on an underwater superoleophobic-oleophobic heterogeneous pattern. The flat circular region shows an inherent underwater oleophobicity while the femtosecond laser ablated region displays underwater superoleophobicity. In a water medium, the oil droplet is restricted to the untreated circle by the energy barrier at the superoleophobic-oleophobic boundary, thereby forming a convex lens shape by surface tension. The liquid lens array benefits from the surrounding water and then overcomes the problem of evaporation. The shape of the liquid lens can be simply controlled by the designed pattern and the oil volume.