Botany meets textile technology

Botanists have discovered an amazing self-cleaning effect in lotus plants - engineers and technicians at the ITV Denkendorf are working hard on transferring this effect to textile surfaces.

What would it be like if we no longer needed to scrub marquees, squeeze shower curtains into washing machines and wear ourselves and our brushes out cleaning dirt from car seats? Could the idea of saving time and work be more than just a dream for those fastidious individuals with exacting cleaning standards? Could it become reality? The ITV (Institute for Textile Technology and Process Engineering in Denkendorf) directed by Professor Heinrich Planck is working on the development of textiles with self-cleaning features. The project is being done in cooperation with the NEES – Institute for Biodiversity of Plants at the University of Bonn and BASF.

Drop of water rolling off a dirty tissue with the lotus effect. As the drops fall, the dirt is washed off. (Photo: ITV Denkendorf)

The self-cleaning effect was discovered in 1977 on lotus leaves but was only protected with patents and the “lotus effect” trademark as late as the1990s. The patent is held by Prof. Dr. Wilhelm Barthlott at the NEES Institute at the University of Bonn. The principle is as simple as it is ingenious. The surface of lotus leaves is extremely hydrophobic. This means that drops of water just run off the leaves. In addition, the leaf surface has a characteristic nanostructure that ensures that water drops and dirt particles only remain on the very nanotips of the plant structures. The contact area is therefore very small. Due to the adhesiveness of the water, water drops carry off dirt particles when they drip off the leaves.

Nanostructuring enhances self-cleaning effect

The physical and chemical features of the leaf surface are what create the lotus effect. Therefore, the effect can, in the sense of a bionic approach, be used to transfer the effect to technical systems. Nevertheless, the experts at the ITV soon realised that the transfer was not as easy as it appeared. Apart from the search for a suitable microtopography, nanostructuring of textiles posed a particular challenge. Chemists and BASF engineers succeeded in developing a specific, nanorough surface in the range of 20 to 100 nanometers.

Water is enough to wash away the dirt on a tissue with the lotus effect. Here, the tissue is shaped like a lotus leaf.

At the ITV, mechanical engineers, chemists, process engineers and textile experts are working on the development of textile products with the lotus effect. Modern microfibre outdoor clothing, which is actually already a high-tech product, is an almost ideal field of application. The microstructure of these textiles supports their self-cleaning effect.

Medicine is also interested in the lotus effect. The ITV scientists are currently investigating whether they are able to alter the surface of implants in such a way as to improve their coating with human cells. In addition, the development of artificial blood vessels was also inspired by the lotus effect. The effect can also be observed in other fluid substances: for example, honey and water-based glue run from the hydrophobic nanostructures of the ITV textiles without leaving any stains. This might certainly prove to be another interesting area for the further exploitation of the lotus effect.

In the textile area, application is not far away. On 6th April 2006, the ITV presented a newly developed coating technology, a textile intermediary and final products to the public. At the same forum, the ITV also presented their “self-cleaning” quality standard which the cooperation partners hope will prevent the misuse of the term “lotus effect” by technically substandard imitations. The quality standard guarantees self-cleaning features based on the lotus effect as well as a technically mature product.

Shaken water is best for cleaning – no additives required

As soon as the first textile products reach the market, only water will be needed to get the textiles as clean as the day they left the factory. This feature ensures that such textiles are a lot easier to clean and also more resistant to wear and tear. In addition, the reduced cleaning expenditures reduce the environmental burden. The economic advantages are clear – both for the public and for numerous textile manufacturers and suppliers who have benefited from this new technology. The ITV has established contacts with numerous companies that are interested in this new product.


leh - 20th April 2006
© BIOPRO Baden-Württemberg GmbH

Further information:
ITV - Institute for Textile Technology and Process Engineering Denkendorf
Dr. Thomas Stegmaier
Körschtalstraße 26
D-73770 Denkendorf
Phone: [phone]
E-mail: [e-mail]