Geek has posted about this super cool video from The National Science Foundation depicting water droplets on various hydrophobic surfaces.
Nature is full of examples of hydrophobic surfaces being used to move water from one place to another, but only recently have scientists figured out how to replicate the same properties with synthetic materials. With a combination of chemical coatings and nano-scale structures, materials science researchers have been able to make water do things that seem almost impossible, and indeed would have been just a few years ago.
The National Science Foundation has put together a fascinating video montage of superhydrophobic surfaces, and it’s probably going to be the best 4 minutes of your day.
Most of the hydrophobic coatings that are in use in products like shoes and cell phones are based on a chemical coating. This is the quick and easy way to repel water, but the materials being developed in labs around the world are superhydrophobic by their very nature. They are made up of nano-sized pillars, poles, or other structures that change the angle at which a falling water droplet contacts the surface. This can cause droplets to bounce right off or be pushed in a particular direction.
Studying the way some leaves repel water has also resulted in engineered surfaces that split water droplets on contact in order to dry the material as quickly as possible. You can see a few neat examples of this in the video.
To take full advantage of these revolutionary hydrophobic surfaces, you also need hydrophilic ones (they attract water instead of repel it). Using a combination of hydrophobic and hydrophilic textures on a single surface can be used to move fluids from one place to another very efficiently. These microfluidic circuits could one day form the basis for advanced, inexpensive medical diagnostic tests. You can see in the video how large volumes of water can be kept confined to narrow hydrophilic channels with a border of superhydrophobic material. This same process could be used to collect fresh water from the air as well.