Self-cleaning effect, superhydrophobic surfaces

The same effect is observed in the opposite way with singeing or calendering, which results in smoother surfaces. On the other hand for such surfaces that have fewer undercutting structures the accessibility of dirt particles and therefore self-cleaning ability is enhanced. The implementation of nanodimensional structures on the fibre surfaces enhances superhydrophobicity and the self-cleaning effect. This is shown in Fig. 15.12. 

In order to prove the superhydrophobic and self-cleaning effect of textile products, ITV issues the quality mark self-cleaning - inspired by nature that makes use of the foregoing testing methods (Eig. 15.13). Additionally, in the testing procedure to this seal of approval the fiber s filament surface is examined with an SEM to qualify the surface structures, underlining the prerequisite of nano-scaled structures for the self-cleaning effect. 

The lotus effect has inspired scientists to design superhydrophobic surfaces for applications such as self-cleaning windows and water-repellent clothing. To understand the lotus effect and other phenomena involving liquids and solids, we must understand intermoiecuiar forces, the forces that exist between molecules. Only by understanding the nature and strength of these forces can we understand how the composition and structure of a substance are related to its physical properties in the liquid or solid state. 

The amazing water repellent properties of many biological surfaces, especially plant leaves, have prompted great research interest. With certain leaves, when water droplets fall on the surface, they can easily pick up contaminants, roll off the surface and thereby clean the leaves. Because the first observation of this self-cleaning phenomenon occurred on lotus leaves, the effect is generally termed lotus effect . Detailed inspection of the leaves showed that micrometer and submicrometer structures as well as hydrophobic materials exist on the leaf surface. The combination of these factors leads to superhydrophobicity. Wenzel [1,2] showed that surface... 

Since Barthlott and Neinhuis first reported the lotus effect, the lotus has become the archetype surface for superhydrophobicity and self-cleaning abilities (Barthlott and Neinhuis, 1997). For centuries the lotus has been known as symbol of purity in many Asian religions. For over a decade, this purity has become a phenomenon within the scientific community, with many studies having been performed with a view to determining the mechanism responsible for their self-cleaning ability. 

Bhushan, B.,Jung, C.J., Nosonovsky, M., 2010. Lotus effect surfaces with roughness-induced superhydrophobicity, self-cleaning, and low adhesion. In Springer Handbook of Nanotechnology, third ed. Springer, New York, p. 1437. 

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