1 nanometer is one-hundredth million meters. For comparison, as shown on the graph, the diameter of a human hair is about 80.000 and the volume of nanometers of red blood cells is about 7.000 nm. From the evidence, a simple request – the size of nanomaterials is about 800 times smaller than human hair.
With such a small size, there are new opportunities and new applications for these materials, which were not possible in “normal” size. Materials in the nano scale retain all the physicochemical characteristic of the material on the macro scale. In addition, however, the materials have number of new properties that are associated with their size and their properties such as color, conductivity, reactivity, or resistance which differ significantly between nanomaterials and macromaterials.
Nanomaterials as compared with the normal materials exhibit:
– Better chemical resistance
– Improved strength
– Better biomaterials biocompatibility
– Better hardness
Hydrophobic effect is sometimes called as LOTUS EFFECT.
The lotus effect refers to the very high water repellence (superhydrophobicity) exhibited by the leaves of the lotus flower. Dirt particles are picked up by water droplets due to a complex micro- and nanoscopic architecture of the surface, which minimizes adhesion.
Due to their high surface tension, water droplets tend to minimize their surface by trying to achieve a spherical shape. On contact with a surface, adhesion forces result in wetting of the surface. Either complete or incomplete wetting may occur depending on the structure of the surface and the fluid tension of the droplet. The cause of self-cleaning properties is the hydrophobic water-repellent double structure of the surface. This enables the contact area and the adhesion force between surface and droplet to be significantly reduced resulting in a self-cleaning process