At a first glance, the image below looks simply like someone opened up an image with Photoshop, highlighted a circle and deleted it. Surprisingly and rather confusingly, the image contains no editing or photo manipulation whatsoever. It’s the blackest material ever synthesized – so black that our brains can’t properly perceive it.
THE BLACKEST MATERIAL – VANTABLACK
Vantablack currently holds the world record as being the darkest man made substance.
Vantablack is so dark that at a distance of 700 nm, it only reflects 0.036% of light, rendering all topographical differences completely unnoticeable to the naked eye.
To understand how and why the Vantablack coating manages to reflect so little light, the chemical structure must be explained.
VANTABLACK IS MADE OF…
Each nanotube has a diameter of around 20nm. To give a comparison, an average red blood cell is around 400 times wider than one of these nanotubes.
THE DARKING MECHANISM
When light strikes the surface of the Vantablack coating, it bounces around the nanotubes. Seeing as the nanotubes are up to 50 µm long – 2,500x their diameter, they end up bouncing around a large amount of times, losing energy with each successive contact.
Due to the fact that the tube is significantly longer than it is wide, the light becomes incapable of escaping. The small amount of light that can escape is what makes up the 0.036%.
Surrey Nanosystems have also made a coating called Vantablack S-VIS which is significantly darker than regular Vantablack. Its structure is very similar to regular Vantablack, except the nanotubes are shorter and form a coral-like structure that traps electromagnetic energy extremely well.
Vantablack S-VIS isn’t as dark in some parts of the electromagnetic scale in comparison to the regular Vantablack, however, depending on angles, it can be darker than regular Vantablack.
Our eyes rely on photons – the particles of light – bouncing off objects and into our eyes to be interpreted by our brain. Seeing as Vantablack emits almost no photons that come in contact with its surface, our brain can’t interpret what it’s looking at.
Even when it is coated on objects with a non-uniform topography, it shows up as an entirely black “hole” looking area on the surface.
WHERE CAN THIS BLACKEST MATERIAL BE USEFUL
Vantablack has become so well known that a plethora of different industries are looking to purchase it and to apply it to their own existing products.
There’s the obvious cosmetic appeal in Vantablack, such as coating cars and forms of abstract artwork that would benefit from having significantly darker areas.
Other applications include, microchip wiring, touchscreens, ultralight wiring and strengthening aerospace components. A microsatellite named Kent Ridge was launched late 2015 which used the Vantablack S-VIS coating.
Surrey Nanosystems uploaded a video to YouTube which explains the differences between their Vantablack with other dark coatings, which helps to explain the differences between them.