superhydrofobic

Superhydrophobic is a term used to describe a surface that repels water to an extreme degree. When water comes into contact with a superhydrophobic surface, it forms almost perfect spheres and rolls off with minimal contact. This phenomenon is characterized by a contact angle of greater than 150 degrees. This high contact angle is achieved through a combination of surface roughness and low surface energy.

The roughness at the micro or nanoscale creates air pockets between the water droplet and the surface. These air pockets, often referred to as a plastron, significantly reduce the actual contact area between the liquid and the solid. Coupled with a low surface energy coating, such as certain waxes or fluorocarbons, this minimizes the adhesive forces between the water and the surface, promoting the rolling-off behavior.

Superhydrophobic properties are inspired by natural phenomena, like the water-repellent surfaces found on lotus leaves, often referred to as the "lotus effect." Applications for superhydrophobic surfaces are diverse and include self-cleaning materials, anti-fouling coatings, anti-icing technologies, and even microfluidic devices. The ability of these surfaces to repel not only water but also other liquids, and to resist the adhesion of dirt and contaminants, makes them a subject of ongoing research and development.