Superhydrophobic surfaces

A glass plate has been coated with a superhydrophobic finish. Water poured onto the untreated portion will reach the boundary of the coating and no further. The water displays a tall meniscus that can be disturbed but still return to the center square. Superhydrophobicity is a result of a hierarchical nanostructure where a layer of particles <100nm are overlayed over particles <100μm. The microsctructures are arranged such that the water’s (and some oil’s) adhesion is minimized and due to surface tension a water droplet will asssume a nearly spherical shape. This effect is found in some plants and insects and is referred to as the Lotus Effect.