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.
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.
- Slippery pre-suffused surfaces, A. Lafuma and D. Quéré, Europhys. Lett. 96 (2011), 56001
- Droplet mobility on lubricant-impregnated surfaces, J.D. Smith, R. Dhiman, S. Anand, E. Reza-Garduo, R.E. Cohen, G.H. McKinley and K.K. Varanasi, Soft Matter 9 (2013), 1772-1780
- Evaporation of Sessile Droplets on Slippery Liquid-Infused Porous Surfaces (SLIPS), J.H. Guan, G.G. Wells, B. Xu, G. McHale, D. Wood, J. Martin and S. Stuart-Cole, Langmuir 31 (2015), 11781-11789