# Why the soldier's black boot shines and the blackest synthetic material on earth

in stemng •  5 months ago

During the one year mandatory service to my nation, I was both fortunate and unfortunate to get an accommodation in a military barrack. I was lucky that the housing was rent-free, but "unfortunate" that I became subjected to a regimented lifestyle of the military. The order, rules, cleanliness, etc. were out of this world. I was particularly fascinated by the officer's boots. Here was the semi-arid part of the country where dust is on everything, and never on the officer's boots. It was black but always polished to the point that it shines and reflects light.

Shoes [CC0] , from Pixabay

This phenomenon of shining boots may even make one wonder if black absorbs all colours, why do we experience reflection from a black surface? The index of refraction has a role to play here. It is constant, for different mediums, which expresses the speed of light waves as it moves from one substance to another. In other words, it merely checks the degree of refraction that light experiences as it moves or leaves a material (medium).

Index of refraction n = c/v
c= velocity of light in a vacuum
v= velocity of light in the medium

Some common index of refraction of some material is enumerated below:

MaterialRefractive index (n)
Vacuum1
Air1.000277
Water1.333
Flint Glass1.57-1.75
Diamond2.417

Looking at diamond's refractive index of 2.417, it means that light travels 2.417 times faster in a vacuum than it does in a diamond. The fast-medium have a smaller index of reflection than the slow medium. Hence light passing through a less dense medium to a denser medium bends towards the normal while the reverse occurs the other way round; if travelling from denser to less dense medium light turns away from the normal.

What has above got to do with black shiny reflective army boots? If a surface has a different refractive index from the air, some of the light that strikes the surface will reflect. The fraction of the light that will reflect is dependent on the angle the light is incident on the surface. The fraction of light reflected is a measure that the Fresnel equations can determine. The Fresnel equations or coefficients, proposed by Augustin-Jean Fresnel, describes the behaviour of electromagnetic wave's reflection and transmission at an interface.

The "shine" on a black object is merely a function of reflected light. The "transmitted" portion of the light merely is absorbed since we are dealing with a black object. A rough and smooth black surface respectively have a different reflective behaviour due to both possessing different refraction index.

#### The Blackest Man-Made Synthetic Object

Vantablack placed against an alummium foil. By Surrey NanoSystems [CC BY-SA 3.0] , from Wikipedia Commons

In 2014, a small British tech company, Surrey Nanosystems Ltd, announced to the world that they had developed a world record holder in the category of the blackest material called vantablack. The name "vanta" is an acronym for Vertically Aligned NanoTube Arrays.

Though, Frederik De Wilde, a Belgian artist objects to Surrey Nanosystems claim of creating the blackest material with nanotechnology. A claim that Surrey Nanosystem refuted since their process is not the same and that theirs is darker than Frederik's material.

Moving on from their controversy, how did they achieve the world's blackest material? Vantablack is said to absorb 99.96% of any light that hits/strikes it perpendicularly at a wavelength of 663 nm. If it absorbs more 0.04% and all frequencies of the electromagnetic wave spectrum, it will become a blackbody, an ideal body that is capable of absorbing 100% of light incident on it. Vantablack holds a record light absorbing capacity.

##### How was that possible?

The answer lies in nanotechnology. Nano describes something tiny. To put it in perspective, a thing that is approximately 40,000 times smaller than the diameter of the human hair. The size is a minute one-billionth of a meter.

An electron microscope shows nanotubes. By Argonne National Laboratory [CC BY-SA 1.0] , from Wikipedia Commons

#### The Making

The vantablack is primarily not a colour, but rather a material. The making involves jam-packing "forests" of hollow carbon nanotubes. According to the website, a centimetre square surface contains approximately 1000 million nanotubes. These tiny microscopic tubes are "grown" using proprietary methods on top of a substrate in such a manner that any light incident on it gets absorbed with just a very tiny fraction escaping. The surface created is now devoid of any colour.

Therefore, unlike the black paints in the market, one cannot just walk into the neighbourhood hardware and home improvement store to buy a bucket or tin of vantablack.

The description of the making no doubt may give off the impression that a vantablack coated material will have a velvety feel to it, but that is not correct. Instead, we have a surface that is smooth.

To understand the scale of the nanotubes, we will use a real-world example of a wheat's height on a farm. The wheat in a farm usually stands about 3 or 4 feet high; if a carbon nanotube is a wheat in the farm, it will rise 1000 feet tall in nanoscale. This compaction and density of nanotubes make vantablack extremely good at absorbing most of the light but susceptible to damage. Hence application of it where there is no protection (outdoors exposed to the elements or where people physically touch it) is still a work in progress.

#### Applications

I guess you already know that the blackest material on earth created by different individuals and firms cannot be just for the fun of it. It must serve some purpose. Though initially created for the space industry to limit thermal cycling, exposure to high vacuum, mechanical vibrations in components in space, etc. Today, there are varied applications for the "darkest synthetic material on earth."

Carbon nanotubes. By User Mstroeck [CC-BY-SA-3.0 ] , from Wikipedia Commons

Since the material for making vantablack does not come cheap, high-end jewellers and automakers are looking at adorning the inside of a watch and making eye-popping super dark dashboard, interiors, etc. on luxury vehicles respectively. This added cost is something those with deep pockets can afford to pay for.

For the artist, due to the super light absorbing power, which can make a 3-D sculptor appear like a 2-D as seen in this incredible Youtube video while viewing the sculptor directly. It stands to reason that there are other mind-blowing "magic" that an artist can achieve with vantablack at the disposal. Presently, an artist, Anish Kapoor is working with vantablack.

References

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I read about that last year I think. I think that it could have a big impact on the fiber optic market. No loss of light down the tube now, or so it would seem to me. That may stretch out the distance that fiber optics could be used.I wonder if it could also be used as a strong insulator against loss of electromagnetic energy. Shielding batteries from EMP pulses. If it can affect light waves, all energy after all is just a different level of wave propagation.

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I don't think fiber optics technology will have any need for a light-absorbing material. But the optical equipment that exist in space, such as the supersensitive infrared cameras need a material like vantablack to absorb any stray/unwanted light from getting to the camera.

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I was thinking more along the lines of not allowing the light to leak from the fiber optic cable, or have other stray higher intensity light wavelengths from interfering with its own light signal, no signal loss thing.

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Ok, you mean to form a sort of magnetic shield around the fiberoptics cables to reduce polarisation of light as it propagates along the medium? I doubt it can do that.

You always teach something new.

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Thank you.

First of all, I'll think thrice before arguing with you face to face, one year in a military barrack!! hmm, Wisdom is profitable to direct.

Nanotechnology has brought improvements to our technology in leaps and bounds, it looks as though if you already have a very good technology, carrying it out with nanotechnology makes it even 100 times better. The good thing about science is it will never stop amazing us with more amazing improvements.

I enjoyed every bit of this (I'm usually focused whenever mention is made of soldiers, I don't take chances, it's an innate something). Well done Sir.

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It was an awesome experience with loads of stories worth telling.

Science is always based in factual evidences and proofs.
This is a lovely concept. It has never occurred to me why their shoes shine so well even though it is made of black.

Blacks from my understanding absorbs light incidented on them this makes them a better absorbers of heat than silver white which reflects incident light.

We learn everyday, thanks for this wonderful expository.
Nice one sir✌@greenrun

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I just used military shoes due to the extra effort to put in shining their shoes to illustrate this effect. The effect is something you can replicate in other black shoes if it meets the same criteria. It is true that dark colours absorb more light and heat, the reason it is never advisable to wear dark colours on a hot sunny day.

Nice one sir green

I always felt there is something different about those shoes and our but we can just ask them because something else might come after the question `if you know you know`

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Just like I told @tundevet, any black shoe can reflect light if polished good enough. Some glossy black shoes will even do that if wiped clean of dust.

I guess this answers the question "how black is black?"

I would have been disappointed if the material had no application coz nanotechnology is not child's play

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I'm glad it didn't disappoint :)

Great article, I really expect a lot more out of these materials in the near future. I even think that the price will drop..

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Yeah @alexdory... Had a good read here earlier on.. and am already getting some more material for further studies on carbon nanotubes

Would this surpass graphene, well we'd find out -- only in the future.

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I don't think their uses coincide 100%, so they can coexist.
I have read a lot on all of them. The future looks promising.

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I don't think their uses coincide 100%, so they can coexist

Oh, yeah.. Definitely not 100%
If you still got some material links, please Dm me once you can, am really interested in these stuff. @alexdory

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They were either videos on youtube from science hubs or articles in the scientific press and magazines. I get those out of Facebook or Youtube subscriptions.

Nanotubes -- these material does not come cheap, looking at the fact that it's an important composition of the vantablack material.

Those military personnel wear it and treat it with uptmost care.. I think I now know the reason why.

Good stuff here @greenrun

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The military boots have got nothing to do with vantablack. I just used the boot to show an example of a black material that reflect light.

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Oh... My mistake. I misunderstood that. Thank you.

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You are welcome.

Black bodies absorbs all light and reflect non.

If a surface has a different refractive index from the air, some of the light that strikes the surface will reflect.

I think that portion I quoted from the post explain to us why their shoe always shine.

I hope you are not a military man too @greenrun.lol

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You are right, that explains the shine. The military are the best of men :)

Its funny how your post describes my exact same situation right now.... Serving in the military Barracks & living a regimented life!

Materials for making Vantablack is pretty expensive & not just anyone can afford it.
Great post @greenrun

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Here's wishing you an amazing service year. Go get 'em! :)

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I'd be through in a Few weeks man.... But thanks All the same Man

I went to a military secondary school. Have always wondered why soldiers shoe are always shinning. Now i know as you have said above. I can remember if we dare step on their shoe back then...it going be huge knock on your head...thanks @greenrun

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It is not only military shoes that can reflect and shine. Any black shoes can reflect light if polished fine enough.

I can just imagine what that vanta watch would look like... Awesome!

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It looks beautiful but the price tag ain't :) You can take a look here for pictures.

Vantablack!!- that's what makes the difference
Amazing post as usual.. I appreciate my military boots even more.

BTW - the shoes on your first picture, are they called car accident?!, am lost here.

Amazing content @greenrun

Green on the run😋

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Those are the type of non combat shoes often favoured by the military and paramilitary organisations. Is the car accident you are referring to a slang or something?

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Is the car accident you are referring to a slang or something?

I just noticed it in the sourcing of your first image @greenrun

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That was a typo. Thanks.

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Anytime green @greenrun

Hello @greenrun

Oh was this the reason? Now I know. It's interesting to know how piqued science is. Always trying to find reasons to even what ordinary persons may think insignificant, and will end up revealing the applications of such phenomenon. This is an instance.

Regards...

@eurogee of @euronation and @steemstem communities

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It is just like Steve Jobs told us, we should stay curious. The more curious we are, the more things we can do and learn. Thank you.

Nice reading from you again @greenrun, so why is this material not used for every black shoe.

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Vantablack is a very expensive material. Covering a shoe with one will make the shoe be 10x or more expensive. A a 40x40x3mm aluminium sample sells for £300 or \$402 or ₦144720. That size is not enough to polish one pair of shoes!

Not only is Anish working with it, but they've apparently secured the sole rights to use vantablack artistically. In retaliation, the maker of the 'pinkest pink' pigment specifically disallows Anish from using their color.

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That's some copyright feud going on there :)

When I opened the post I was expecting a story like the one u did on Nana can't remember the surname especially while reading the first paragraph but then I walked into a science class.
Thanks for the lecture though, I would not have learned of vantablack on my own

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No, this was not a story, just a blog on science. Thank you.

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Yea, I saw that... nd ur other science posts they are really good and informative

Another great post from @greenrun.
I thought this is going to drive me off but now more enlightening as expected.
So, black shoe can reflect light if polished well enough.

I'm going to take this to practice.

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Thanks.

Wonderful post never think about that in life very nice topic you covered today thanks for sharing

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Thanks

Nice reading this post... Thanks for the knowledge u impact to me this morning.

informative post...

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Thanks.

learn something new from you, thanks for this information....

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