Technological Applications of Superhydrophobic Coatings:Needs and Challenges

Superhydrophobic coatings is an interesting area of research. The superhydrophobicity and the causes of superhydrophobic surfaces is discussed first. By superhydrophobicity we mean the property by whch the device has extreme water repellency and nonwettability of a solid surface. nearly spherical droplets are formed in any other surfaces but in the other surfaces , non-continuous films are formed. The example of this phenomenon can be seen in the natural world such as the lotus leaves and the duck.
The techniques used for the purpose of creating the artificial superhydrophobicity are lithography, plasma treatment, chemical vapour deposition to layer-by-layer. fluorinated polymers, silicones and silanes are used as a coating on the rough surfaces to provide them the property of superhydrophobicity. These surfaces have attractive behaviors such as the self cleansing and anti-sticking and water repellency. Some of the attractive features of the implementation of this technology can be: Self cleaning glass, superhydrophobic paints and other architectural coatings and textiles.

causes of superhydrophobicity
The Scanning Electron Microscopy (SEM) photograph of the surfaces such as the lotus leaves shows that there are tiny bumps on the surface of size 5 to 10 µm high and 10 to 15 µm apart. There are wax coatiing on the surface. a thin layer of air is trapped in this bumps. This layer reduces the area of contact between the water droplet and the solid surfaces. This gives rise to the property of syperhydrophobocity.