The Lotus-Effect


The Lotus plant (nelumbo nucifera)

The fact that surfaces of blades cannot be sprinkled is well-known and well examined. It was overlooked however large that such surfaces are also almost not to get dirty.

While on a smooth surface the dirt particle are only shifted by the water drop, they adhere on a rough surface at the dripping while unreeling the page and are washed off in such a way.

This connection was only examined in detail in recent time and occupied experimentally.

Because it can be demonstrated particularly well at the large shieldlike pages of the holy Lotus-plant (Nelumbo nucifera), the symbol for purity in asiatic religions, it was called the "Lotus-effect".

If water drops roll over a the blade of a Lotus, then they take up all particles and remove them from the page. Basis of the Lotus-effect are extremely roughened up blade surfaces at those water and particle practically do not adhere.

 


Left: water drops on a normal, smooth surface
right: water drops on a Lotus plant


The surface of a lotus plant under a microscope


A drop of water on a lotus plant under a microscope

 The special structuring of the surface and the ability for the regeneration of the waxes make the Lotus-effect to a large extent insensitive in relation to natural influences. It behaves differently with anthropogenen influences, e.g. environmental chemicals. To these belong also Tenside, which must be used in large yardstick world-wide in plant protection agents, in order to ensure an active substance accommodation. They change the fine structure of the wax crystals, and make the pages wettable for water. As a consequence, dirt particles aren't removed anymore from the blades and under unfavorable circumstances, there are sporen, mushrooms or bacteria remainig, which also can lead to a relieved infection of the plant.

The Lotus-effect represents a very effective biological model system, with which artificial surfaces can be developed that reject dirt, since it is based on a purely physicochemical basis.

There are numerous fields of application (front coatings, roofs, autolacquers), in which such surfaces bring many advantages, and can lead to a clear environmental discharge by saved cleaning costs. In co-operation with the industry, one operates at present to transfer the Lotus-effect for technical applications. It will surely still last however some time, until operational products come on the market.