Superhydrophobic Microtextures

Schematic representation of a superhydrophobic microtexture

Lithography can be used to create a surface with a regular pattern on a micro scale. The surface can be made hydrophobic, and then the spaces between the raised patterns on the surface infused with a liquid. The result is a SLIPS surface. This is shown schematically above and in image (b) below. Image (a) below showns a microtextured surface without an infused liquid, and image (c) shows the same surface after infusion with oil.

Schematic illustration of SLIPS surface
(a) Microtextured surface, (b) Schematic illustration of SLIPS surface, (c) SLIPS surface

The SLIPS surface is very slippery when tilted. The video below shows a water drop sliding on a SLIPS surface tilted 0.8°. Even though this is a very small tilt angle, we see that the drop moves very easily.