Self cleaning Plastic surface like lotus leaf

A self cleaning plastic cup based on the same ideas that nature used to self-clean: the Lotus Leaf:
Imagine having a plastic cup that can be reused without washing, simply because contamination has no chance to stick to the surface. The ideal natural properties of the Lotus leaf’s self-cleaning surface are ideal for many applications and consumer products.

Work underway by the Applied Laser Technology Group of the University of Twente has shown that such products are possible by using an ultra fast femtosecond laser.
The secret of the Lotus leaf can be found in numerous tiny pillars with a wax layer on top. Water drops are lifted by these pillars, get into a spherical shape and can simply not cover the surface. Dirt gets no chance to stick to the surface via water. The spherical drops roll off and take dirt particles with them. Max Groenendijk applies the laser in two separate steps. During the first step, the surface gets a fine ripple structure. This is caused by a special self organizing effect that works for almost all kinds of surfaces. Whenever the laser removes some material, a pattern of ripples is formed at the bottom. It is possible to influence this pattern with parameters like speed, intensity and polarization.
The second step is writing a pattern of perpendicular lines. What remains is an array of pillars. These pillars then already have the fine pattern caused by the first step. This double structure replaces the need to have wax on the pillars, and makes the surface highly hydrophobic.

Read more: http://www.utwente.nl/nieuws/pers/en/archive%20press%20releases/cont_07-002_en.doc/