Superhydrophobic Microtextures

Lithography can be used to create a surface with a regular pattern on a micro scale. An example is shown in image (a) below. The surface can be made hydrophobic, and then the spaces between the raised patterns on the surface infused with a liquid, as shown schematically in image (b). The result is a SLIPS surface as in image (c) below.

(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.

Water drop moving on a SLIPS surface tilted at 0.8 degrees.