Vantablack
There are a lot of black things out there, some of which are blacker than others. For instance, there are everyday black items such as shoes.
There are matte black paint jobs, like this car:
And there are even special, fancy black paints used by corporations like NASA, which are really, really black. The below substance is called “Aeroglaze Z306” and is what is painted onto the Hubble Telescope to minimize the amount of light reflected.
In fact, Aeroglaze Z306 absorbs 99.1% of all light which hits it. That’s pretty black.
But, even Aeroglaze is not the best. Let me introduce you to my friend, Vantablack. Below is a strip of Vantablack on top of a square painted with Aeroglaze Z306. You’ll note that the Vantablack is so dark that it makes the Aeroglaze look blue in comparison.
And here’s what happens when you shine a laser on Vantablack and Aeroglaze Z306 — note how the laser is completely absorbed when on the Vantablack.
Just how dark is Vantablack? Well — the version invented in 2014 absorbs 99.96% of all light. We’ll get into some of the more recent innovations in a second, but first, let’s learn a little more about how Vantablack works.
The Science Behind Vantablack
Vantablack is one of those shitty half-acronyms for “Vertically Aligned NanoTube Arrays”. That being said, Vertically Aligned NanoTube Arrays roughly describes the structure of the substance.
In particular, the material is developed by growing a “forest” of parallel carbon nanotubes on a substrate using a chemical vapor deposition process. If grown correctly, the nanotubes can be perfectly aligned such that when light strikes Vantablack, it get’s “stuck” inside of the forest of nanotubes, and continually reflects back and fourth until all the light gets dissipated as heat, rather than reflected back to an observer.
The only way light gets reflected is if the incident light happens to hit the “tip” of a carbon nanotube, rather than hitting the interior of the lattice. However, because of how minuscule the carbon nanotubes are (each is one fiftieth of a millionth of a meter in diameter), the material is 99.95% free space, and therefore only ~.05% of the time does the light hit a tip and get reflected.
A researcher at the company that produces Vantablack explains the substance like this:
“To understand this effect, try to visualize walking through a forest in which the trees are around 3 km [1.86 miles] tall instead of the usual 10 to 20 meters [33 to 66 feet]. It’s easy to imagine just how little light, if any, would reach you.”
The material also has a few other very nice properties, such as the fact that it is extremely lightweight (since it is almost all free space), it is heat resistant, and it is quite flexible. Vantablack also does not exhibit “outgassing”, a phenomena common among some other materials made with carbon nanotubes, where some of the material would sublimate over time.
But, it gets better
Now that you know a little about how it’s made, let’s return to my statement that the version invented in 2014 absorbs 99.96% of all light. Well, scientists have been hard at work since then, and in 2016 the research team at Surrey NanoSystems announced that they had an even better version. How black was it? Well, the material is now so dark that no spectrometer is able to measure how much light it absorbs.
This company is also doing a lot of other crazy shit. For instance, they have a spray version of Vantablack, called Vantablack S-VIS, which absorbs 99.8% of light and can be sprayed virtually anywhere, and they also have now developed an alternative, non nano-tube coating which can withstand human handling (whereas traditional Vantablack can not):
What is all this used for?
There are actually a huge number of applications for making really, really, really black things. Any form of light sensing object (such as telescopes, sensors, cameras, etc) can utilize this material to prevent stray light from entering and to improve the resolution of “images” in very low-light scenarios. It is already being used in a number of satellites for this very purpose.
It can also increase the absorption of heat in solar-materials (since virtually all light that hits it gets converted to heat), and can be used as a thermal camouflage in military applications. A number of orders have been placed from the defense and aerospace sectors for Vantablack.
Finally, it also has various artistic uses. For instance, it could be used in luxury goods for a truly unique aesthetic, or in amusements parks or other similar venues in order to create a truly surreal experience.
Sadly, Nature beat us
While Vantablack is amazingly cool, it turns out that some animals have developed similar methods for camouflage and light reflection via evolution. A notable example is the Gaboon Put Viper.
The black scales on the snake’s back actually have nano-ridges with a virtually identical layout on the nano-scale as Vantablack. While the snake’s ridges definitely don’t absorb as much light (they absorb ~11% of light), it is awesome that nature was able to come up with the same core design.
