The Asian Watermoss is an aquatic fern with leaves about the same size as a penny. Like the Sacred Lotus (Nelumbo nucifera), water runs off the Watermoss’s leaves, but microscopic analysis shows a completely different mechanism of action: in the Watermoss, specialised structures each hold a tiny air bubble. When its leaves are completely submerged, they retain a layer of air over their entire surface.
‘Salvinia-effect’ surfaces have great potential to be used as drag-reducing coatings. A layer of air on the surface of an object moving through water reduces the friction between the two, and a Salvinia-effect coating has been shown to reduce friction by over 30%. If applied to ships, such coatings could reduce their fuel use.
Salvinia-effect surfaces are also extremely good at absorbing oil from the surface of water, and are being investigated as materials to help clean up oil spills.