Details in the process of making "blacker than vantablack" coatings (part 1?)

[@wunkewldewd]

Hey Ben, I did my PhD in experimental physics (in fact, using a few materials/techniques you use in this video). I don't have any tips for this problem, but I wanted to say that your experience here is very typical: we'd frequently read about some cool new process, say "huh, seems simple enough, let's try it", and find that it was near impossible to reproduce from the paper. Research and publication is supposedly about reproducibility, but I suspect that typically, some key step is left out. I'd guess that it's some fraction malice and some fraction not, where either the authors don't want it to be reproduced (before they can get several more publications), or where they either didn't realize there was something special about their lab setup, or they've always just done something in a way that's actually unique to them, so they didn't realize they should report it.

[@grahams5871]

This video also made me think about the reproducibility crisis, and the missing step is the expectation of reproducibility. If the journals had the workflow: 1. publish precise steps for new thing that need to be good so they can be reproduced 2. wait for and collaborate with third parties to reproduce your results 3. when repro happens, publish paper, citing helpers of course. There are lots of problems with competitive researchers of course, but the idea is to get the reproduction of a result into the recognition and prestige of the result and into the workflow of publishing.

[@TheBackyardChemist]

Sometimes it is the need/desire to make a messy project presentable. Maybe you try to do something, but it does not work, but you get a new related idea, repupose stuff, get some decent results, but now your setup makes no sense at all for the project because you initially wanted to do something else. Sometimes in long running projects, you might forget to record something, or think it is unimportant, then the project meanders a bit, and when you finally write the paper your realize you have no way of knowing some specific detail from a year ago, so you give your best guess or omit that detail. I feel like admitting that you have no idea about a specific detail harms publishability more than omission. This is of course not ideal, better planning is better, but rarely do research plans survive contact with reality/experiments completely intact. Of course this is a rather charitable interpretation that may not be always applicable...but I had to point out that poor recordkeeping or organization can also lead to papers that are all over the place.

[@AG-pm3tc]

This video legitimately made me fear for the scientific process, at least in the experimental sciences, because if a paper from a place like M.I.T gets published with such holes, think what usually goes on in the field...

[@carneeki]

I understand this is pretty common in the world of psychology, particularly when it comes to reproducibility, which is quite concerning.

[@tricky778]

@@TheBackyardChemist This is a serious failure that you describe. If you set out to find something amazing as fast as you can then you miss stuff. If you set out to find out just something, anything, but really find it out then I don't think you would have missed a step because you'd go back and check each thing you say against general market availability of materials and see if what you say is generally true or else you find out what the key is to make it work.

[@cchloveher]

I work in the MIT group you referred to in the video and I forwarded your video to the first author of the paper. Hope you guys can talk directly.

[@kylezo]

!!! UPDATE WHEN PLS?

[@BadGuySVK]

No response because it's either intentional or it's gonna make them look incompetent.

[@alexandrezani]

If these people were postdocs or PhD students, they likely were ridiculously overworked and "some guy on KZbin couldn't reproduce your result" will go on the giant pile of "things to do some day" along with sleep, having lunch and talking to their partner. (Grad school is brutal) If they graduated, they probably no longer have access to the notes and equipment and just don't have answers. (How detailed are going to be your answers if someone quizzes you about a specific project 2 jobs ago?)

[@rusticagenerica]

May God bless you and congratulate you for working at the award-winning MIT !!! ♥

[@ДенисДавыдов-у1з4ы]

Gordon Freeman?

[@thethoughtemporium]

Some thoughts since I've also read up on this sort of stuff a lot. One thing may be to try a different catalyst. I've seen ferrocene used a lot and should make smaller diameter nanotubes. I haven't seen them use hydrogen to reduce it, normally it's just painted on and heated under argon and will just decompose to pure iron crystals on the surface. Since it's basically iron and carbon, the carbon just burns off and so long as there's no oxygen present it shouldn't form any oxides. Also then you dont need to work with cobalt which is always nice. Beyond that, It's odd that you're using only co2 as the reducing gas. I've almost always seen hydrogen mixed in as well to reduce any amorphous carbon. It increases the pucker factor for sure which is why i haven't tried it, but may give you a much better result. For comparison, hydrogen is used as the reducing gas when growing diamond as it's much better at getting rid of any unordered carbon. The next would be to start with that black velvet. As long as it's made of natural fibers you can carbonize it by heating it under argon. Then paint it with the catalyst, and try growing the nanotubes on it. Should get you a muuuuuch darker end result. For the darkening foil you may want to go the other way rather than degassing the solution. Add more oxygen. If it only went dark when exposed to the fumes, to me that screams it needs more oxygen than can be attained while submerged. Or add a drop of soap or tween to the solution to help break the surface tension. Another way to do nanotextured aluminum is to wipe it down with a dilute HCl solution. I used that trick to texture aluminum when I was making supercapacitors and it seemed to help add lots of surface area. EDIT: updated once I finished the video.

[@cambridgemart2075]

How does the carbon "burn off" if there's no oxygen?

[@thethoughtemporium]

@@cambridgemart2075 It just forms some carbon on the substrate which actually helps get the process started. Or you use hydrogen to reduce it away

[@jeffreypomeroy6173]

I actually use carbon dioxide as my reducing gas when forming extremely high surface area carbon foam. It produces carbon monoxide and reduces at a slow steady rate. Hydrogen is much more aggressive and you have to worry about leakage of hydrogen at temps.

[@cambridgemart2075]

@@thethoughtemporium So it sublimes, got it!

[@number_three]

@@cambridgemart2075 Boudouard reaction

[@aaron4820]

"Damn it, you aren't suppose to read the detail" Also, the easy way to to make aluminium dark is by soaking it in 20% salt in near boiling water, then turn the lights off.

[@Jeremy.Bearemy]

Instructions unclear: made whole room dark

[@d.t.4523]

@@Jeremy.Bearemy Clarification: Turn off the lights in your competor's lab.

[@pavel9652]

Interesting, I think I made dark aluminium by accident 2 years ago. I have a salt grinder in the kitchen that has an aluminium square rod in it. I have not used it too often and the salt absorbed moisture from the air and formed clumps. The metal corroded with dark blemishes where it was in the contact with salt and even had some deeper corrosion pockets. It probably took a few months and the salt was clearly wet to the touch. So it looks like the method could work.

[@trentoncarr]

Throwing some valid shade to the state of recent research papers. Having seen the same in Electromagnetic papers lately.

[@trentoncarr]

@@guptadagger896 Electromagnetic research papers, motors, transformers etc

[@apefred]

seen basically the same in mechanical engineering/ engineering mechanics papers

[@NitFlickwick]

How can you get your patent and sell you micro-startup, if you make the process easily reproducable in the paper?

[@senselessnothing]

NitFlickwick Then the paper is no more than an ad

[@fluffy_tail4365]

@@NitFlickwick because you get the patent? Like the patent itself is publicly visible too

[@TechIngredients]

There seems to be an increase in scientific papers containing results that can't be reproduced, but this MIT paper sounds awful with vague descriptions and inconsistent methods; why trust their findings? 0.1%...REALLY?

[@emilychb6621]

Nah it's been like that for ages. Try looking up 30+ year old chemistry papers. They leave out everything required to quickly reproduce it. It's like a cake recipe where they only give amounts for a couple of ingredients and then say bake at 300°F. But for how long? Nah not important. This is especially bad for stuff that would lead to patented drugs on the market. Like major steps being left out so without experimenting you can't ever reproduce it. We had the same problem with Nitro Benzothiazinones about 10 years ago in the research group I worked at. The methods section wasn't really usable, we basically had to come up with our own way of creating the base frame of the molecule to then further modify it etc. Like they had to just reflux at 80°C for 8 hours. Which had a yield of about 1% of the ring closed step. In reality refluxing at boiling for just two hours had near complete conversion..

[@Dartheomus]

@@Chriss12345 Look up EJ Corey. Like @Emily Chb was saying, this kind of crap is prolific. EJ Corey got his PhD from MIT, and he teaches at Harvard. He's regarded as one of the best organic chemists ever. That said, papers that come out of his lab often show chemical transformations that have 5 synthetic steps with isolation and purification in between each, and they net 99.5% yields. Anyone in chemistry knows this is absolutely impossible, and there's even a nickname for reaction yields that are impossible. "Corey Yields." Well anyway, everyone in his lab has to be able to be this good or you don't get published and you don't get your PhD. It got so bad that he's actually had brilliant young minds commit suicide due to the pressure. It's sad.

[@emailsharedbyafewpeople4105]

Dartheomus I didn’t find anything about 95% yields

[@Dzeno2010]

​@@Chriss12345 No it's just one of the best rated schools XD The rating system is just messed up which is a part of the problem. Education should be the number 1 thing that is measured combined with research (output). American universities are extremely good at marketing their research which makes them well known giving them high(er) ratings. Not saying MIT is a bad university it is still a really good university, just saying it's probably overrated like many US universities. Unfortunately many universities across the world are following this trend and you see universities acting and becoming more like big companies instead of being education and research centers first. However research is also expensive ... So it's not like this is all very weird or strange. Lastly there's also a lot of pressure to publish and sometimes the researchers don't have that data themselves because it either wasn't recorded or couldn't be recorded in their setup. Although even if you know the approximate value it will be frowned upon if you put numbers that way into a paper so it can be much easier to get a paper accepted if you just don't mention them to begin with (data is be measured, simulation/calculation is a prediction, however estimating numbers is in experiments is not accepted often when it could have been measured or you can't be sure what the value should be). Also papers would need a lot of extra info to be reproducible and sometimes things get overlooked because in the lab that value is normal and always the same. Many academici would like it to be better but changing that can be very difficult, especially considering most of the power is with the university/company/lab people work for, the publishers, and investors.

[@CommonApathy]

Welcome to publishing in a Journal! They don't even proof read it before publishing it lol.

[@UnauthorizedExpression]

Put salt water on aluminum and then place it in direct contact with steal. It will turn dark. I used to work at a hurricane shutter company and that was a big no no that ruined aluminum often. First remove any oxidation from the aluminum.

[@Alexander_Sannikov]

i think it's possible that there was some electrolysis happening in the original paper because of some random steel paperclip holding aluminium or something stupid/unintentional like that.

[@assaf127]

@@Alexander_Sannikov The sonicator's bath and basket are made out of stainless steel usually, it could be that they just put the aluminum pieces straight in there

[@garret1930]

@@Alexander_Sannikov electrolysis makes sense to me, I've only ever had aluminum turn black when I used it to make a Layden jar.

[@alfoncejean8826]

yeah using electrolysis instead of a current generator is probably best

[@ca5cad3xml7sx4]

You just described an electrolytic cell, some call it a battery XD

[@bensmith3304]

The paper should have a corresponding author listed, and you should definitely feel free to email them with you questions. A hard lesson I learned in my PhD is to contact the authors before even getting started, as some key details are often left out in the name of being succinct. In my experience, they will respond with the actual person who made the sample, and very likely will share their lab protocol and any tips. Unfortunately, by convention what didn't work is not published, even though that oftentimes is the most key bit of info when trying to reproduce a protocol, hence why a corresponding author is always listed. If they are like most scientists, they will be stoked that you found their study interesting.

[@judge462]

Did you look at the vertically aligned sample under the electron microscope? Im curious if that looked globular or if you see more consistent structures

[@MichaelMantion]

YUP First thing I thought of is I want to see what it looks lke.

[@AppliedScience]

I have special plans for that piece. I'm going to make an SEM animation of the nanotubes being pulled out of the forest, and rolled onto a spindle!

[@bengmo64]

@@AppliedScience ooh I want to see that!

[@billythebake]

@@AppliedScience I'm getting on the waiting list to see that one, too. FWIW, I can't WAIT to see the little tiny chainsaw that the little tiny logger uses... Goofing aside, this is really interesting - keep up the good work!

[@stanwow6081]

@@AppliedScience I recall tweeting you a while back about growing these and trying to put NANOTUBES under your microscope, thank you for doing this. Im stoked to see more.

[@JohnDlugosz]

21:00 I used to be involved with densitometers. The proper angle is to have the light source normal to the surface and the fiber pick-up at 45 degrees, or vice-versa. You can also obtain a calibration plaque cheaply enough if you want real figures.

[@Hallowed_Ground]

Lol yeah right. Sure thing big guy.

[@athmaid]

@@Hallowed_Ground what's your problem dude

[@ThirstyJuicebox2]

There are enormous career pressures in material science (more engineering for lots of synthetic work like this) to discover “novel” materials. A simple hypothesis from an influential professor can lead any desperate postdoc to make a few optimistic rounding choices or instrument configurations. That isn’t necessarily going on in this instance, maybe there is some small detail of sonicating aluminum in salt water that was miscommunicated or forgotten. In any case, if you’ve done synthetic work, especially cutting edge stuff from top journals, you know that not everything is as it wants to seem. (That said, a very large amount of synthetic work is as solid as it seems. Total number of publications is growing rapidly, so the absolute amount of irreproducibility is growing too. There is a very positive, if painful, movement starting in science to upgrade the whole system and hopefully minimize a lot of this.)

[@aarondcmedia9585]

My first thought: replication crisis 2.0.

[@android61242]

@ 🤣

[@ronzawora]

@ Don't give the ad agencies any new bright ideas. They think everything and everything should be monetized...

[@KuzmanGanchev]

Did you try contacting the paper's authors? Not sure if they would have time to debug with you but they should be able to tell you what kind of ultrasound machine they were using and what kind of salt.

[@UpcycleElectronics]

Isn't it obvious that paper based communication alone is a primitive relic of the past? There should be an entire program dedicated to visual media for scientific documentation. Any published papers that are not accompanied by a video demonstrably proving the findings should be considered incomplete. Science is not a for profit endeavour for selling grossly overpriced periodical subscriptions. The primary form of human communication is purely visual. It is now possible to communicate in our primary format. The sole use of written publication for communication is as primitive as the past use of latin long after it was a dead language. Employing someone capable of producing a video is a basic skill as essential as Math and Language. Anyone resisting such required skills should be considered unfit for the job. It is not hard to assign them someone with a modern skill set to make up for the disability. Everyone carries the required tools in the form of a camera on their phone. Not requiring it's utilization in documentation is an atrocity akin to living one's entire life without one limb because of tradition and a lack of common sense.

[@lucasmoore4997]

re: metal solubility in ethanol - the acac salts referenced in the paper aren’t acetates, they’re acetoacetates. Way more soluble in organic solvents.

[@finchisneat]

I was JUST gonna ask if he's sure he's using the right salt. My guess is with your post.

[@billsmathers7787]

I noticed this too, but the experimental procedure at 10:20 calls for the acetate salts. I'm guessing acetoacetates were for a different experiment.

[@MaxSeidel1]

Going by the Formula on the picture (acac), yes, but in text they say acetates.

[@AndrewBoraas]

I see black oxides on 7575 aluminium, 7575 will stain or get black spots on it if left in machining coolant for too long, or ive forgotten parts is a wash tub of water and dawn soap and seen black spots.

[@didiwin78]

not 7075? It seems much more common.

[@keithyinger3326]

Not sure what alloy most cast parts are made from? Things like alternator and motor housings. I melt things like that and remake them into art. Occasionally i'll etch a design into things with hydrochloric acid. It turns it black where the acid touches. I should note my etching acid container is not pure HCL. It started out that way but over a year or so its probably got a decent amount of dissolved metals in it , i know for a fact there's zinc in solution as i've used it to de-galvanize some fittings in the past also. So in the end i guess what i'm saying it i'm not sure if its the Al alloy, or my acid concoction that turns it black. I also make items from alum-bronze and etch them. I tried some brand new HCL, left them in for 30 mins and they hardly etched at all. Re-buffed them, and put them in the old contaminated acid and within 5 minutes they were beautifully etched.

[@xxportalxx.]

@@keithyinger3326 hcl and aluminum creates black residue, that's the reaction that teenagers use to blow up soda bottles haha

[@keithyinger3326]

@@xxportalxx. ya true. I know some of the black rubs off but it does leave the surface darker than it was. Was kind of surprised he didn't try any acids. Well he did try adding a small amount o his salt solution but not straight acid. I wonder if it would work for him to darken anc etch the surface?

[@xxportalxx.]

@@keithyinger3326 yeah I was wondering bc a common lab technique for making salt water is mixing sodium hydroxide solution with hcl, and if their molarity was off that could leave unreacted hcl in solution

[@sean_vikoren]

It is great to see you wading into the replication problem. I also really like how you are sharing your trials and tribulations. Actually doing science is almost always really messy, and it is often presented as click clack snack. Your contribution here is really appreciated.

[@Schwuuuuup]

I regularly turn Aluminium foil pitch black: Whenever I cook a special kind of dumplings that are made from cut up white bread made into a dough. The dough gets wrapped in aluminium foil and put into boiling salt water for 20min. Normal tap water (Here in Germany we do not really have additives like chlorine in it)... and about as much salt as you would use with pasta. the inner side of the foil gets coated with olive oil but I don't think the dumpling dough or the oil have anything to do with the foil turning black. The only thing I could think of what would be different to your experiments is, that I really boil the water and don't use very much salt. If you want pictures , I could cook them tomorrow, my girlfriend would be very happy to get those dumplings ;-)

[@georgplaz]

for the sake of your relationship, i hereby request pictures :o)

[@Schwuuuuup]

@UCh7slur2-MCA3VEJTfmloSA I never ever tasted or smelled chlorine in German tap water, but in USA I had. Not everywhere and it was many years back so from my personal experience I would say US tap water has (or had in some places) more chlorine in it than German water in general - even though the treatment plants may use more chlorine to fight an acute thread. A elevated level of chlorine from treatment plants in German tap water makes it to the news - in USA not so much, at least not everywhere.

[@j9260]

What is the boiling salt water in? A steel pot? Other commenters link steel with the blackening of aluminum

[@Schwuuuuup]

@@j9260 The type of Pot I used doesn't seem to make a diffrence... some of them are stainless steel but one of them is coated on the inside so that the water would not touch the water (the coat is scratched, so maybe there is a bit of contact, but I think the pot is aluminium)

[@Schwuuuuup]

@@j9260 The salt seems to be the MAIN-Reason. I used to cook my dumplings without salt in the water and had no blackening happening... then one time I had water ingress and the dumplings tasted awfull since then I use saltwater.

[@brenesrob]

As a grad student, normally the best way I have found of reproducing experimental papers is contacting the author directly about any questions you might have. Many times, the discrepancies are not done maliciously but because of simple errors (not always, but generally), so asking the author directly helps clear up any of these.

[@zakqwy]

This is really cool! We followed a similar procedure in a lab class a few months ago to grow CNTs. My group only managed a few hundred um, but another team got well past a millimeter. One trick we used during the SEM analysis: use a razor blade to carefully slice into a few spots on the sample, then view it at an angle using the microscope. We initially thought we only had soot; similar globules and so forth. It wasn't until we cut into a globule and SEMed it from an angle that we saw a tiny forest. Re: Al darkening, I agree with other commenters -- send a note to the researchers. Other changes from your setup: we used helium rather than argon as a 'safety gas'. Our apparatus also had a built in 6mm Lexan blast shield, and everything was performed in a fume hood. Probably not needed if you're careful about avoiding leaks. And our substrate was directly heated using a bit of highly doped Si with a current running through it, and a pyrometer feedback mechanism.

[@zakqwy]

Add'l thoughts: as you suggest in the video, our substrates were prepared in advance with a several deposited catalytic layers. On top of the Si substrate: ~100 nm SiO2; 10 nm Al2O3; 1 nm Fe. Our input gases (H2, He, C2H4) were preheated. Probably not necessary for an externally headed tube furnace (as opposed to our directly heated samples). Recipe: - 1000 sccm He for 3 minutes - Preheater to 1020 C - H2 to 250 sccm, He to 140 sccm, 2 minutes - Substrate to 825 C, hold for 30 s - C2H4 to 120 sccm, 30 minutes - C2H4 and H2 off, heaters off, He to 1000 sccm for 5 minutes - He to 120 sccm until cool

[@GlennHamblin]

I'm always a bit bummed when research can't be duplicated. Thanks for another great video Ben.

[@____._____.]

I am going to start using high pucker factor in my daily vernacular.

[@rewolff2]

Ben, My guess is that one of the things that you say: "doesn't seem to matter much" does matter. Did you try reaching out to the MIT guys? About replicating stuff: Back in the mid seventies my father was a PHD student and tried replicating a paper that said that doing liver transplants in rats was easy. They tried for months, but as soon as they put the rats back on their feet, they died. Turns out one of the drawings in the paper was of the rat on the operating table (i.e. upside down) and not right-side-up. (or the other way around). My father ended up contacting the guys in Japan who wrote the paper.... "yeah that happens if you do it upside down".

[@altersami9660]

Yes, as much great things he do, I wince every time he says "doesn't seem to matter much" or "I don't think it matters". After all these variation and test you did, you're just going to waste all that effort with an unknown variable? That's bad science. The silliest, most inconspicuous things turns out to be important in many case.

[@butt_hero]

Wait, so they put in the livers upside down? That's hilarious

[@hellomynameisaustinw]

You're always so humble in your videos. Hope to see you globally recognized some day 😁

[@georgplaz]

the thing with humble people is, that often they don't strive for global fame. so maybe you don't want to wish for that ;)

[@fej6980]

You can dissolve Al in concentrated NaOH solutions so maybe dilute NaOH in combination with ultrasound could give you the roughened surface (a similar process was used in a paper (doi:10.1016/j.jallcom.2017.01.243#) where they created superhydrophobic surfaces) an alternativ could be making porous alumina by anodization however I am not sure on how well this would work in your case (for example doi: 10.1038/nmat1717) The holes in Aluminum can also be observed in our small lab ultrasonic cleaner (as far as I know a consequence of cavitation bubbles forming and locally corroding the aluminium)

[@UnauthorizedExpression]

A published research paper that isn't repeatable? Imagine my shock. lol

[@georgplaz]

@@googleeatsdicks no matter how good their reasons are, it's still not repeatable. so it's of no use to anybody

[@EnlightenedSavage]

Research papers are repeatable, that's the point. If they are not then they have been proven wrong and are retracted

[@UnauthorizedExpression]

@@EnlightenedSavage If only that was how it actually worked. I believe Veritas did a study that found that only something like 20% of all published scientific papers were repeatable and papers only become popular based on how many other papers cite them. It's been totally corrupted and has rendered the entire practice worthless.

[@_BangDroid_]

To be fair, the exact alloy wasn't tested. But I would be surprised if that mattered

[@bobsagget823]

@@EnlightenedSavage moron

[@thetruthexperiment]

The styling on that electron microscope is SO sick. I absolutely love it.

[@TimLF]

Just email the researchers and ask them.

[@georgplaz]

i thought the same thing 😅

[@UnauthorizedExpression]

20 bucks says they never respond.

[@grindel80]

@@UnauthorizedExpression they will respond. just call then - phone not mail

[@AsshunterPL]

Researchers often answer, but in the way so you still don't get the full answer and you have to search for yourself. It's their work and they often put some false numbers so you don't copy them easily and don't steal their future (probably) work. I, kinda understand them.

[@LordZordid]

@@grindel80 Exactly what I was thinking. I have good results with calling people. They might not be completely forthcoming but if you ask the right questions and steer the conversation you can almost always get the answer you are looking for. Also be really nice, use their name often and be honest.

[@professoreggplant9985]

You are indeed a scientist. I hope one day you invent(discover) something truly remarkable.

[@nophead]

When I was a kid I accidentally found how to make aluminium black. I naively tried to etch a PCB in ferric chloride in an aluminium tray, doh! The ferric chloride burnt through the bottom of the tray and what was left was blackened IIRC. It was nearly 50 years ago! Later in life I worked on the design of an electronic photobooth and we bought a commercial test card to set up the camera. It had a printed grey scale but the last grey was black felt and the black was a hole into a box lined with felt. The hole was probably about an inch wide and the box about a 4 inch cube.

[@alfoncejean8826]

ferric chloride + coper + aluminium tray = have fun with the clean up!

[@kevCarrico]

yes... a light trap - not only useful on a film/video reference chart, but as a way to subtract light from the subject being photographed (i.e., “negative fill” light).

[@ab_ab_c]

@@kevCarrico The action lab did a nice video on a light trap. Here's a url to the vid: kzbin.info/www/bejne/gKCvdnyfr8ZseMU

[@dougankrum3328]

Ferric chloride....aluminum...Yeah, I once tried to speed up some copper PC board etching using one of those immersion heaters with the aluminum 'coil'....that went well for oh....about 2 minutes....

[@sefarkas0]

I did the same thing as a kid many years ago trying to etch a PCB in aluminum baking trays, the ferric chloride and copper dissolved the tray enough to leak onto a multi colored carpet in my bedroom (the 60's) so the stain wasn't very apparent. I would impress my friends when I showed them that that area of the carpet was conductive with an ohmmeter.

[@dionysoskartel]

Mr. AppliedScience I love your unerring curiosity and commitment to science. You remind me of a tech-oriented Mr. Rogers in all the best ways.

[@PlasmaHH]

Ask them maybe what they did ;) I would suspect that they did a short ultrasound and then soak and then short ultrasound again and so forth. Aluminum capacitors need a huge surface area too, maybe figure out how they prepare those?

[@mph8759]

There’s a lot of great technological creator content here, but Ben your work is to most sophisticated and absolutely amazing!

[@deanarvonen]

Would you consider using charcoal cut perpendicular to the grain for your initial medium? Charcoal from very straight grained species like Finnish pine would presumably have quite a vertically aligned surface once cut, and also contain the micro porosity you’re interested in depending on the density of the original wood.

[@pyotrilyichtchaikovskyii6638]

Finding a replicable paper is an Odyssey these days.

[@MusikCassette]

can you finetune the frequency of the ultrasound? When I visualize the prosess, I think you will have to either create a standing wave or absorb all the echos. So you might get a reliable pattern of pressure differences.

[@quackerzdb]

I'm just making a comment to recognize the quality content you produce. It's very rare on this platform and deserves attention.

[@complexobjects]

Well that paper sounds like a mess. Incomplete description and inconsistencies just ruining your day lol

[@MandrakeFernflower]

Biochemical papers are often even worse

[@christianh2581]

Yeah, sounds like one of those findings nobody can ever reproduce, not even the original researchers.

[@yaidontknowwhattoput]

Crazy amount of effort put into these videos. Hope you enjoy the work as much as I like watching.

[@gu4xinim]

"We are talking about pretty dark stuff here", Indeed we are.

[@elsea8901]

Henrique Grolli indeed, were talking Burnt Reynolds dark.

[@KetansaCreatesArt]

There is actually an actual dark story behind vantablack.

[@Karl_Kampfwagen]

Goths: How do we make black shirts BLACKER? This could change the world. Army: Shirts? That's a cool idea... 🤔 We were just putting it on planes and helis.

[@joecobra48]

blm

[@lashamartashvili]

In middle 80's, when I was a kid, I read how to darken aluminum in a russian DIY magazine "Modelist Konstruktor" and used that method for transistor heatsinks with great success. I remember that it was a simplest method imaginable and I thought I'd remember it whole life, but later, after some 15 years, when I really needed it again, I couldn't remember how to do it, neither could I find the recipe. What I remembered then and remember now is that it was as simple as immersing aluminum into NaCl, or NaOH, or the mixture of the two, but when I tried, I failed every time on that later occasion. No ultrasound was needed nor was recommended to use as it was a DIY project in that time and country. The only other chemicals I had access to by then were NaHCO3 and CuSO4 so I couldn't have used anything other than what I mentioned here. Hope, with your diligence, it helps. P.S. the resulting colour was far from being as dark as black velvet or even black paint.

[@hctimitch7501]

I have had aluminum turn black when placed in a NaOH solution.

[@randomblogger2835]

so black you can't see it anymore... maybe handy if you need some hydrogen.

[@abefroman5191]

Right before you mentioned texturing the surface, I was thinking of minimizing the tapered base of the tube maybe by growing it through a screen of some sort but texturing would certainly deflect the light coming off the base

[@randomelectronicsanddispla1765]

I wonder if the frequency of the ultrasound is influencing the size of the cavitation bubbles to a big extend. Maybe why yours didn't work

[@kissa02]

Some ultrasounds have a sweeping function, where it goes thou a large range of frequencies. I have one at work, so I can try doing this tomorrow

[@GrafRucola]

Random Electronics and Displays is there duty cycle in ultrasound thingies. maybe another variable

[@sugarbooty]

@@kissa02 I'd love to hear back, please let us know

[@Geolaminar]

@@kissa02 Replying so Google notifies me when you comment next

[@user255]

@@Geolaminar Same

[@devrim-oguz]

It strangely gave me comfort knowing that we can see the surface of those materials with a flashlight.

[@TechyBen]

Vantablack: £1000 a tin. Amazon: £2 felt. Vantablack has left the chat.

[@djmips]

good luck applying felt to your complex shaped object

[@shanewickham8667]

@@djmips What good is the Blackness used for?

[@adfaklsdjf]

@@shanewickham8667 i assume there's all manner of optical devices that could benefit from having very non-reflecting surfaces in some way

[@CommodoreFluffy]

@@djmips u know that stetsons and bowler hats are made of felt, right? felt can be made to match almost any surface with a little bit of steam forming and sewing.

[@skylerlehmkuhl135]

Velvet, not felt. Felt isn't nearly as dark because the fibers are mostly horizontally aligned.

[@rayethridge9971]

Thanks for pointing out that the "quartz" tubing for the patio heaters was not really quartz. I was ordering parts for a new vacuum degassing system based on this cheap source of quartz tubing! You saved me a lot of heartache and expense.

[@lespaul85]

Spinal Tap's Nigel Tufnel: "It's like, how much more black could this be? And the answer is none.... None more black"

[@luke_fabis]

These are sleep deprived grad students living on instant ramen. And their ultrasonic cleaner is in a shared space, in an old, likely moldy building. I very, very strongly suspect it wasn't just a simple salt water bath. There was probably a combination of biocorrosion and galvanic corrosion occurring on that aluminum foil. If you've ever found a derelict scrap of aluminum foil in a grimy shared kitchen sink, it was probably a dark gray color.

[@NoLandMandi]

Warning!!! "we are talking about pretty dark stuff here" 22:42

[@manyirons]

I have what started out as a shiny cast aluminum garlic press from Zyliss. The one single time it went through the dishwasher it turned very dark. Now, over two decades later, it's still dull gray even though we only ever wash it by hand. No more aluminum goes into our dishwasher after that episode.

[@404nf1]

I've seen aluminum foil turn dark while doing the silver tarnish cleaning trick. Granted most of that was probably some aluminum and sulfur compound, might be worth a shot.

[@nickf3242]

I've been curious about vantablack since I learned of it's existence. This was a very interesting video. Thanks for also showing the flashlight trick, as a "couch scientist" watching a KZbin video and not being familiar with the actual surface, it was truly enlightening to see the effects of light close up to the material. I have a request/idea though... You should somehow "wrap" your furnace to mimic an Easy-Bake Oven lol

[@Bencarelle]

Have you seen any of the paint development that Stuart Semple has been doing? I think this might be a fun way to get Black 4.0!

[@BRUXXUS]

That was my immediate first thought too! LOL I was a kickstarter backer for 3.0 and have painted a few small 3D printed objects with it. It's very weird stuff! I have a bigger art project I've been planning on... I really need to finish it.

[@WaltSorensen]

I remember some mechanics in a forum saying to avoid putting aluminum in an ultrasound with detergents as it will cause the aluminum to go black. might be a starting point for further investigation.

[@zZBucketsZz]

I wonder if they really used sodium chloride or if it was a different salt compound and the person who wrote the final paper assumed it was table salt.

[@coctailrob]

I wondered that also. Also aluminium forms an oxide layer when exposed to air, I wonder if that was removed first.

[@palewriter1856]

Clearly those ""researchers"" didn't expect the likes of YOU coming along and exposing their "diligence." EXEMPLARY scientific method, as your admirers have come to expect! Thanks for the warm and fuzzy chuckles to start my day!

[@kassenbon]

Did you consider using anode foil from electrolytic capacitors? It is etched already (the level depends on the rated voltage of the capacitor)

[@Volt64bolt]

I have kinda done this with charcoal, it works surprisingly well, basically I put the charcoal in some ethanol and put in in a pressure cooker on top of some glass

[@Scrogan]

A few thoughts. Try putting a piece of aluminium in a hot solution of concentrated sodium hydroxide, with stirring or ultrasonic action. I’ve noticed that the aluminium part of the handle of my saucepan is a relatively dark colour from being put in the dishwasher, so perhaps it might work for you too. There might be a difference between cast and extruded/rolled aluminium too, or in how it was heat-treated. Trying on proper unsealed electrolysed aluminium might also be worth a shot. But something more likely to work, unroll an electrolytic capacitors and use its aluminium electrode. The surface area should be pretty damn high. Not sure if you tried it already but growing them on soot-coated aluminium sounds like a good idea too. And consider increasing your CO2 “etchant” concentration.

[@Geolaminar]

NaOH is known to eat aluminum too, so there might be something there.

[@usmcbrat2]

I'm not much of a chemist, but have been a telescope maker for 30 years, and so my interest lies in a cheap/flexible/durable/lightweight/blacker-than-black/thermally-inert material to use as a coating for the inside of a telescope tube that will absorb stray light. Your video is interesting. Thanks!

[@samykamkar]

Awesome video as always!

[@migueld2456]

Samy!

[@bdnugget]

My hero!

[@rolandosantos6861]

Great work and great videos! I love the deep and detailed layman analysis you give them. Obviously lots of hard work and talent. Thank you for what you teach us.

[@NixKanal528]

Washing aluminum in a dishwasher makes it dark.

[@bradley3549]

Only if you use a good caustic dishwashing detergent.

[@uncleouch9795]

I just recommend this in a way. I handwash my dishes, and usually throw a bit of bleach in the utensils for a soak. My Rada knives turn dark grey. There is no doubt they're etched (I restore antique Swords) I know what I'm seeing. All I have to do is Scotch Brite them for a couple seconds and they're Brite and Shiny again.

[@_BangDroid_]

DW detergent is nasty stuff. Makes me wonder why they make the tabs look like candy a lot of the time.

[@vooveks]

​@@_BangDroid_ Totally. They really go on about storing them out of the reach of children, but yeah, how about they make them look horrible and unappetising if they care so much?! The trouble is, of course, they need to make their tablets stand out to shoppers making a choice.

[@geoffrjjjjjjj]

We make our aluminum pans dark by frying stuff on them.

[@mattfrevel8286]

Too many comments to see if anyone has already suggested this, but you may want to look into the frequency of your ultrasonic cleaner. I was a maintenance tech at a label company. They purchased an ultrasonic cleaner to clean "Anilox" rolls (rollers that applied ink). The first cleaner they purchased was too aggressive and eroded the ceramic coating off the rolls. The original cleaner had a fixed frequency of 35 kHz. They had to get another ultrasonic cleaner that had an adjustable frequency between 50-100 kHz. I was told that the lower frequencies are more aggressive than higher frequencies. We operated at about 70 kHz. On a side note, I thought it would be a good idea to try and clean the aluminum exhaust port on my shotgun with it. It ended up eroding the aluminum and turned it dark with an orange peel texture. Had to purchase a new exhaust port.

[@davidellsworth4203]

For the lower-bound reflectivity measurement calibration, have you tried a hole in a box that's black both inside and outside? (I searched the comments of this video and found that John Długosz also suggested this a week ago.) I think this calibration may be quite important, as the light from your lamp may be reaching the input fiber to the spectrometer in paths other than the desired one (for example, it may be diffracting around the baffle you're using).

[@flach99]

My guess is they used some sulfur compounds like sodium bisulfite, sodium sulfite or even sulfide. One reason is that it is not easy to keep aluminum surface free of oxide in a salt solution, especially for a week with progressively increasing surface area. These compounds would help with scavenging oxygen and oxide and reduction as well. The chemistry should work still, with sulfides present on the surface and might help subsequent adhesion of different metals. Also there were some reports on using sulfur compounds to reduce graphene oxide, thus the chemistry seems favorable on all aspects. On a further note Thiols can definitively darken metals. Combined with chemisorbtion of the mentioned "catalysts" this actually would seem like a feasible approach. Also they do advertise the use of sodium containing detergents in some of their work (angewandte paper in particular) and bisulfite can infact be found in those. Another thing to really consider, the naked metal surfaces are really active, especially if they are nanoporous, and dirt could really stick to it. Cleaning surfaces is the most tedious part. Clean glassware is key, e.g. dont use soap to clean your glasware, it will end up on the activated surface. Also, come to think of it, Nickel content might be vital in these materials. There is a reducing agent which is called "Raney Nickel" and is prepared from a nickel and aluminum alloy. It is used for desulfurization in some cases. Section on catalytic reduction is of interest in your case: en.wikipedia.org/wiki/Raney_nickel I would check this review in particular>>>> 10.1002/aenm.201703259 Graphene oxide reduction with bisulfphite doi: 10.1021/jp107131v Chemisorbed thiols on metals: 10.1007/978-1-4613-0327-5_5. I hope I am not throwing you off of the real answer. Great videos Ben! Keep it up and thanks for the content!

[@AdelAlouani]

I have a feeling that the thin layer of aluminum oxide that forms naturally with ambient air (oxygen) is harder to ultrasonically treat than the aluminum itself. I'm not sure if the acid concentrations you used were high enough to break down that oxide layer.

[@ultratorrent]

I'm thinking machine the surface before chucking the aluminum pieces into the salt water. The aluminum oxide layer protects the underlying metal incredibly well.

[@melody3741]

@@ultratorrent Something I think you’re not really understanding and a lot of machinist don’t really understand too is that aluminum oxidizes instantly. Like, faster than you could ever perceive. After a longer period of time it will grow thicker, but it is impossible to completely remove mechanically.

[@ultratorrent]

@@melody3741 dang chemical processes ruining my simple solutions!

[@DubsnSubsSessions]

Certain grades of aluminium (7075 I think is one) will go black after being suspended in a 1:5 water/sodium hydroxide solution. In anodising its called smutting and its removed in a 5% nitric acid solution. No idea if that's relevant at all and I've never dried a smutted piece to see how black it really is but it looks extremely black.

[@adamsiwek7995]

Have you tried black 3.0?

[@siirinsahibi]

Hi, I am doing my Phd now on producing CNT’s with CVD in cold walled nanotubes and in situ growth of them on aluminum. Instead of Asetilen I use Ethanol. Some hints. Catalyst preparation is key for it. Homogeneously and very thin coating is key. Sooth you see on the surface is due to low temperature on the catalst surface. Flow cools it down, flow should realy slow. And temperature must be already high enough before the acetylene flows over. I admit that most of the papers are irreproducible.

[@Alexander_Sannikov]

instalike for referencing Tech Ingredients' channel. i mean, let's be honest, I'd like this video anyway, but that even in itself is enough.

[@stupot8413]

I'm also glad @tech ingredients is finally getting some recognition. :D

[@_BangDroid_]

'twas a nice name drop

[@Sekir80]

@@stupot8413 Yea, I first found them looking for laser projection stuff, and he made something very fancy. I loved it!

[@FieldsOfFlesh]

Someone may have already offered this information but, my first highly technical job was thin film optical coating. We did everything in house. Part of coating is cleaning shielding with a bead blaster and then washing it very carefully to remove all the debris. While doing this (in deionised water not salt), occasionally these dark patches would bloom on the metal surface that could not be wiped off. Someone told me that if you leave the metal in the ultrasonic too long this can occur. I assumed it was contamination working its way into the roughed up surface of the metal but it is possible this was occurring. It never turned black but I'd only leave it for a few minutes at most.

[@KnowledgePerformance7]

Seems like a sketchy paper to me. I hope you can get it to work cause it sounds like a really awesome project

[@Darkone173]

Hello! It seems in the paper they use Iron acetylacetonate, which is soluble in ethanol. I've used 1:1 water ethanol solutions of Iron acetylacetonate for the synthesis of magnetite before.

[@craigsmithe4981]

Could it be that the M.I.T folks are publishing papers hoping no one checks there work?

[@georgplaz]

i don't think they made a poor paper on purpose. it takes a lot of skill to write good papers.. maybe they were sloppy and had a side effect they were not aware of.. or the just forgot to write down some important detail. maybe the results were inconsistent and they didn't mention that this almost never worked..

[@ShubhamBhushanCC]

Probably they are idiots who have patented the real process and have presented a very rudimentary method for the general public. Self censorship based on patents is the worst damage to science.

[@josephwendorf6982]

All of the etchants I have used to etch aluminum samples for metallurgical analysis have a small amount of either hydrofluoric or nitric acid (google Keller's etch and Kroll's reagent). You need these strong acids to dissolve the oxide layer; hydrochloric isn't strong enough. However, these etchants are literally designed to give as smooth and flat a surface as possible so we can see the microstructure. But maybe if you use one of these etchants prior to the saltwater bath, you will have more success. The aluminum oxide reforms quickly even at room temperature, so be quick in transferring it from the etch to the saltwater. A small catalytic amount of hydrofluoric or nitric acid in the salt water bath might be helpful too.

[@michaeldiakakis4581]

It seems to me that is the issue here, the oxide layer: it is very hard, stable and inert; it makes aluminium what it is. If one took it off then plain chemistry would be allowed to do the job.

[@lnisbet]

@@michaeldiakakis4581 possibly using a dilute mercuric salt will disrupt the oxide layer. although there would be toxcicity and environmental issues to be considered

[@signalworks]

you played us like a fiddle with that black velvet off amazon e_e

[@Doping1234]

Your tube furnace setup reminds me of the test stations we built for my dissertation on electrochemical properties of ceramics. What we did was adding a KF flange to the tube - my special station was designed out of a corundum tube with a aluminium flange glued together with epoxy. Of course you have to consider thermal expansion, but as long as your tube is long enough there shouldn't be a problem. All the utilities (cantilever for samples, thermocouple, electrical feedthroughs, gas ports,...) were implemented in an opposing flange and could be reliably sealed. We even managed to build a tube furnace out of YSZ and turn it into an oxygen pump to do experiments in hard to reach oxygen partial pressures. If you want to further functionalize your setup feel free to contact me.

[@asvarien]

Sounds like the researchers are either telling some fibs or they really haven't described their method very well.

[@absurdengineering]

Not Dave “very well”, lol. Looks like they just made it up or have no idea what’s actually in their beaker. Maybe they have some spiked kitchen salt. Maybe iodine is important?

[@timng9104]

a few years back, i have evaporated aluminium in a poor vacuum that resulted in blackish aluminium/oxide film. but aluminium oxide is high bandgap transparent. that dark film could be a texturized aluminium which is useful for this application

[@DirtyRobot]

Might be worth removing the oxide layer from the aluminium first. Once you have it etched then let the oxide layer establish again.

[@jrmbayne]

What do you think the acids did?

[@jhyland87]

Out of curiosity, I googled what a car looks like in Vantaback (instead of just flat black) - and it's pretty badass!

[@sylvelk]

Should have called this video "His Dark Materials" to get all the clicks from the new BBC serie !

[@luddebosse1439]

You can etch stuff pretty well by just soaking it in salt water, attaching it to ground on a 12 v dc powersupply, taking a cotton swab an connecting the positive end close to the soaked cotton and then just running it across the surface. Usually 12v digs quite deep so maybe something lower would create more nano-scale indentations.

[@Hirudin]

I've had aluminum parts turn dark in my ultrasonic cleaner. This happened a couple/few years ago, but here are some details that might be helpful... 1. The parts that seemed to be the most susceptible were 7075. 2. The black coloring took-on the pattern of the wires of the basket of my cleaner. The most succinct description I could give is that it looked like the wires "blocked" the black color. The part ended up with black squares separated by light (unaffected, or less affected) lines. (Squares = holes in the wire mesh, lines = the wires.) 3. I was merely trying to clean the parts, so they were probably in the cleaner for 10 minutes and certainly less thsn 40 minutes. If Ben sees this and wants me to give more detail, I can record a video as I'm 95% sure I still have at least one of the blackened parts. I also have an inspection microscope/camera setup that might be useful. LMK!

[@andrewjohndurrant]

Yeah I was going to suggest that he as a look at what alloy of aluminium was used

[@i_never_asked_for_an_alias]

Man i love this videos, but i always get so jelly about all the equipment one has at his hand not to mention even having the space to make such a lab.

[@NicksStuff]

Alright, I've got to ask: can you grow your carbon nanotubes onto carbon nanotubes?

[@1FatLittleMonkey]

That was my first thought. Start with the best lumpy version and start again at the catalyst step. My second thought was: Start with the black velvet.

[@athmaid]

@@1FatLittleMonkey I don't think the velvet is gonna like the furnice lol

[@1FatLittleMonkey]

@@athmaid True. (Although I wondered if in a reducing atmosphere, it would just carbonise, giving the nanotubes even more structure to grow on.)

[@DivineWerezwolf]

I think a collaboration video with NileRed would be fun for the chemicals side. Also it would be curious to see Ferrofluid as catalyst particles and what structures you could get out of that.

[@GrafRucola]

Need Oled for watching this :D

[@oddjobbobb]

I have used a cheap glass beading tool with ruby powder to etch the background of engraving in 14k gold and was surprised the first time because the etched area was very dark grey. It looked like sterling silver that had been colored with liver of sulphuric. But no chemical had been used. A few nights later I woke up in the middle of the night and realized it was dark because the ruby powder had produced such a finely etched surface that no light (less light) was reflected.

[@VincentGroenewold]

So, my take-home message from this is "buy the most expensive things on Amazon, so you're sure it's right". ;)

[@andymouse]

I think my "take away" from this is "buyer beware"

[@Themoonisachees]

at my work i'm the guy people ask when they need to order new computers or parts, and when you have the budget to buy say, the same model of battery but it costs 30$ more, you do that. it's not uncommon for companies (especailly in the public sector) to just go with expensive stuff just because the budget allows for it (we're talking about 1-time orders here).

[@VincentGroenewold]

That’s true but most of the time to meet the budget, otherwise next year less is given. :)

[@brucehaddow2666]

OMG! Can't wait to get my $2.85 USB microphone.

[@chiphill4856]

Love watching your process. That's quite a lab you have accumulated. SEM for the win! Good luck w the nano tubes!

[@StormbringerMM]

In the comments: “Throwing shade on the paper” is the dad-joke of the year!

[@Elfnetdesigns]

We're just throwing SHADE at paper to see what sticks....

[@karlm5022]

Great Work!! Be cool to show if you could do a pull test to see if you have a carbon nano tube forest. It looks so cool when you see them being pulled from a slide, not many videos out there of it.

[@AdrianTechWizard]

Maybe they used potassium chloride instead of sodium chloride. It's all called salt.

[@photonicpizza1466]

The paper specifies that it's NaCl. "The Al alloy sheet and Al metal foil were immersed in 10 wt % NaCl aqueous solution with bath sonication until the desired structure was obtained." It could be worth trying different alkali salts, but as other commenters discussed, it's likely that it was an electrolytic reaction between the aluminium and the steel wall of the sonicator, mediated by the salt solution.

[@SciGom]

By the way, your videos are awesome and most of your projects related to electron gun and CNTs synthesis overlap with my PhD topic. All the best man.

[@KingJellyfishII]

This guy just casually says "so I looked at them under my electron microscope" cos yeah we all have one of those lying around.

[@djmips]

At one time, he kinda had two. One was a unit he built himself!

[@vintyprod]

This videos are incredibly valuable. Thank you for producing such thorough experiments.

[@tomarnd8724]

I wish I had seen His Dark Materials so I could make a joke here

[@jacklewis1]

I have, but can't think of one

[@yazidkeraichia2858]

Excellent......apreciate the maner you explain the problems that occurs in the practical expérience. Thanks many Time for that. Bravo.....

[@zax1998LU]

Uh Oh! Looks like the paper has a reproducibility issue! Time for it to go back to peer review

[@unclvinny]

My experience in grad school (chemical physics, high-resolution spectroscopy) was that researchers were very happy to answer any questions about experimental setups if you simply write them an email. Some details on your setup, what you've tried and the problems you've had, your theories, etc can go a long way towards establishing your credibility if you're not operating in a professional lab. (Although, of course I have to say that I'm amazed by your equipment, persistence and creativity!) In material science, as some commenters here have said, there may be more pressure to leave out important details in order to preserve commercial rights or whatever, but my approach would be to assume oversight rather than malice. Curious to hear what you find out!