You may have heard that a lot of the technologies we see today are inspired by nature, especially in the nanotechnology space, and the lotus leaf is no exception. If you stare at water droplets enough (like I do everyday as a hobby), you will notice that they “wet” different surfaces, differently. In other words, each droplet maintains a specific shape and contact area with the surface, depending on the delicate balance of forces at the interfaces.
This observation is what has led to the lotus effect, which explains the super water-repelling property of lotus leaves, but way cooler is the answer to why the leaves never collect dust. The secret is in the micro- and nano-scale rough surfaces coating the leaves that allow the droplets to hold tight rather than sprawl across the surface it touches. Dust particles are carried with the spherical droplet as it rolls off the lotus leaf.
Since it’s discovery, smart nanotechnologists have applied this principle to various products ranging from paint to glass windows, basically anything that they feel people would like to keep clean. The range of innovations coming out from this discovery include 2008 red dot product design winner, Nanobrella, which looks like a completely innocent black umbrella. But take this umbrella out with you and give it a go, you’ll definitely notice something different.
Remember all those times you brought your wet umbrella indoors only to create a puddle on the floor beneath it? Well, the Nanobrella’s subtle innovation was to make the fabric surface super water-repelling by coating it with a lotus leaf-like surface, so water droplets glide off the surface before you head inside.