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'I can't put metal back together.' then cuts metal and tries to put it back together. Scientific method at work. I love you Steve, make it tangible for us all.
“Cold welding” doesn’t actually have to happen in the vacuum of space. From experience I know that if you polish two quartz glass plates very flat and smooth and then stick them together, they will permanently bond as well. It’s pretty awesome!
but fo the case of metal it has to happen there, because like stated in the video, the metal will oxidise. still, does that mean that if fast enough, it is possible to rejoin the metal before oxidising?
@EternityForest Yes, metals *can* be amorphous - but only if you treat very specific alloys under very controlled conditions (see Wikipedia on "amorphous metal"). This will never happen "in nature". By what I read the first samples were produced in the 1960s.
I think the mechanism that puts the pieces back together is supramolecular interactions. The polimer chains are functionalized, at their ends there is an additional bonding, like a puzzle piece. So when you put them back together the puzzle pieces at the end of the polymer chains meet the other puzzle piece.
Unintended cold welding in space also happened on one of the Gemini missions, when they opened the hatch for a space walk. As the hatch hinges opened, the scraping between the two metal parts of each hinge cleared away the oxide layers enough so that the two parts of each hinge started to weld together in the open position, so when the walk was over they had a hard time closing the hatch.
Interesting! Unfortunately though, a quick Google search led me to articles that say that while cold welding was originally thought to be the culprit, a SPRING that failed to compress was the real cause of the hatch not closing. Still, it's an interesting phenomenon that I had no idea about.
Asking the question "Why DONT things heal or stick back" is such a great explainatory tool here! I wish some of my teachers had that way of explaining stuff back in the day.
A part of our group happens to be working on exactly such polymers, so I am somewhat familiar with the topic. There are 3 main ways to get self-healing polymers (sorted from least likely to most likely to explain this polymer): 1) Simply using a highly elastic resin, which causes stress to deform the material rather than break actual bonds. Over time and sometimes with a bit of heating the original shape is restored. An example of this being used is the "scratch shield", which is a highly elastic clearcoat used by Nissan to give their car finish the ability to heal moderate scratches by itself. Clearly your material has bonds fully broken upon tearing, so this is not the technique that's being used here. 2) Separated reservoirs of unpolymerized monomers and initiators/crosslinkers/catalysts. These can be either capsules or vascular systems spread evenly throughout the polymer. Upon injury, the monomer spills into the cracks and comes into contact with the initiator/crosslinker, causing it to polymerize and heal the injury. An early example of this is the use of Dicyclopentadiene monomer capsules that, when released after an injury, are polymerized by Grubb's Catalyst through an olefin metathesis reaction (doi.org/10.1038/35057232). The healing process uses up monomer and thus can only be performed a very limited number of times. In case of a full tear, the spilled monomer would polymerize on the loose end. Once fully polymerized joining the ends would no longer cause the polymer to heal. It seems unlikely that this technique is being used in your material. 3) Reversible bond breaking and formation (Also called "Intrinsic self-healing"). Polymers of this type have specific functional groups that can connect and disconnect with corresponding groups in a reversible manner. After a tear, rejoining the ends causes loose chains to reconnect to each other, healing the polymer. Closed chains can also be opened and then rejoined to form new links. There are numerous ways to achieve this, some examples include: 3a) Reversible formation of covalent bonds, for example via Diels-Alder-/Retro-Diels-Alder reactions (DOI: 10.1126/science.1065879). Some chemical bonds can be reversibly broken and reformed. After joining the ends together, chains in both ends can break apart and recombine with chains from the other end, reestablishing covalent links. Usually, energetic triggers like heating or UV-light are required to facilitate the mending process. You did not use any such triggers, so this is probably not what you have. 3b) Reversible supramolecular bonding. I am quite certain that this is what makes your polymer mendable at room temperature. There are several interactions that can cause polymer chains to stick to each other without any covalent bonding (ionic attraction, coordinative bonds, hydrogen bonds and π-stacking interactions). These can sometimes also be broken and reestablished at room temperature. You can imagine these supramolecular polymer networks to be like ball and stick magnet toys for children. Your sticks are short polymer chains with negative endgroups (ionic groups or chelating Lewis bases) and your balls are positive metal ions. The combination of both can form large networks of interconnected or entangled chains. The sticks can be flexible, but are not broken apart easily. However, the forces connecting balls and sticks are much weaker and so these connections can be rearranged with a relatively low activation energy, causing the material to stick to itself easily even after being fully disconnected for a long time. Even lower activation energies would be needed for hydrogen bonding networks (replace opposite charges with hydrogen bond donors and acceptors, H-bonds are significantly weaker than ionic bonds). An example for this is published here (doi.org/10.1038/nature06669). I think self-assembly via hydrogen bonding is the most likely explanation for the behaviour of your polymer, though of course I can't say for sure. An interesting example of an elastic polymer that sticks to itself but not other stuff is Parafilm, which is just a mixture of polyethylene and wax. It can't truly "self-heal", but it goes to show that even much simpler polymeric systems can show some of these properties. I just wasted an hour of my time to write this... oh well.
As so many other have pointed out, THANK YOU! For taking the time to write this all out! Such an interesting topic and sharing knowledge is never a waste! It's the most human of things to do. We are a curious species, hard wired to soak up knowledge and share it with others 😀
I'm an injection molding process engineer and this is one of the most interesting things I've ever seen on the internet. Making flow fronts "re-bond" after they go around a core or other feature in an injection mold is a very difficult. We look at is a minimizing the weld line as you can't make these polymer chains truly re form. Typically this is done with greater injection speeds or higher temperatures. Albeit, greater injection speeds induce shear, therfore.. also heat related. Very very cool video. Thanks Steve!
@littletimmy well he sliced his pinky almost off. Got surgery and then only that finger got stuck down like he’s making a fist. (If that makes sense) he let it be for a few years, went back in and they said there was nothing they could do besides chop it off, so they did. Now he has four fingers on one hand 😂
@littletimmy well, I’m not saying he’s dump😂 more so I mean, he probably has put in a lot of work over the years to learn all these things, but it’s not like you need a degree to do it. (So I don’t think he’s stupid, you just don’t have to be a genius) It’s just on the job learning for a long time. The machines are actually pretty complicated and some of them have like 40 buttons or touch screens. And you have to know how to download the info from the computer onto the machine, but I think that just takes knowing how to open files from a USB stick onto the machine. Also the molds in the plastic injection machines are anywhere from about $8,000 to like $200,000. It just depends on the size, how complicated it is, etc. so the fact that he’s the main engineer guy means he’s proved himself to the company with his knowledge and productivity! Also you have to be hella strong to move those things. One of my brothers lost a finger cause he wasn’t paying close enough attention when putting a mold in the machine 😂 I bet this guy is just your average machine mechanic/operator who has learned his specific trade well!
Dude I am actually blown away and baffled by the oxidation explanation. I just assumed that when you cut something (specifically metal) all the particles just naturally start to reorient to compensate for the new gap in space that is created and so when you would try to rejoin the two points they would just naturally start to repel because of the new orientation of the atoms would cause electrons from one piece to be repelling of the electrons on its counterpart and so on and so forth... I really want to see two solid pieces of metal rejoin into a singular piece in space right now oh my God that sounds amazing
@Riccardo Boa Fair point. Without any research, my first guess would be that gold also oxidizes, just that it's not visible. After all, it's not completely inert. But I'll check, and edit in the answer below Edit: It seems that it actually does cold-weld to an extent, and that most gold surfaces are just not clean enough to do it
@Charlie Monroe Because this is a science video, it attracts a science based audience. The type of people who go out looking for this kind of information. Every comment section of every video is it’s own sort of bubble. A convention of people with a common interest of whatever the subject is about. Which is why it’s very interesting to read the comments of videos you know nothing about and be an observer to a bubble you’d never normally see
There is another issue with cutting a metal and sticking it back together no one is mentioning. The serration. It is easy to cut a polymer and have the two pieces touch evenly, since it is soft, but the same is not true for a metal.
There is this "self vulcanizing" (not sure if they're called that in english) rubber strips you can buy that does this too. They're been around for ages. Really cool stuff, I think it used to be popular for handles of different kinds before single piece stuff became cheap.
I just discovered this channel a few days ago, but it didn't take long to notice and appreciate the recurring appearance of Patrick Stewart. His appearance in the various contexts is, quite plainly, comedy gold. Thank you for mixing scientific learning with light hearted humor, it makes learning of new concepts that much more enjoyable.
Edit: continued the video and you spoke of this... It is very much possible to "cold weld" metals, but only if the parts are completely flush and without any oxidation. Depending on the success of the cut, the material will be just as strong as if it was never cut in the first place. Dad went to a metalworking school and had his practice at a forge. He saw the process and even though cold welding is never perfect, I found the idea bonkers and fascinating.
At Uni I did a project on self-healing materials, taking inspiration from Mussels. We were trying to replicate the self-healing properties by making an organometallic aerogel. Was really interesting but the scope ended up becoming multiple PhD thesises (no idea how it ended, if it has yet)
I may have experienced a self-glueing sticker once. This vid left me thinking if it was something similar. It was in an airport, a self-service baggage drop-off station automatically printed the long paper strip that you attach as a tag to your bag, with its identifying information. I remember the tag had one printed paper side, and another plasticky side that surprisingly didn't stick to your hands but glued firmly to itself when you bent it around the handle of your bag and made it touch itself. I remember being baffled that it didn't feel like the familiar adhesive side of a sticker at all. It didn't stick to the handle of your bag either which made it really convenient to detach later without leaving residue. Has ayone else ever come across this?
I used to always ask myself as a kid why cut things can't be put back together. Then I graduated at Chemistry but never realized how obvious it is LOL Prob because I work with water so no time to think about materials anymore. Thank you for pointing it out! This self-healing polymer is indeed very interesting
Fantastic explaination, even if you aren't sure. I was trying figure out why I'm able to puncture a film on a bottle of insulin so many times without destroying it. Easy to understand and funny, too. I'm a fan. Thanks!
"Cold welding" totally blew my mind, and learning about it made it much easier to understand how a similar effect is possible here on earth. Awesome video!
@YamaNeko it really doesn't work that way they used to think metals would wildly stick to each other in space but it's really not the case unless you manufactured it in space it's already covered in oxide We routinely do touch welding of copper on earth but you have to press it together *REALLY* hard etc
I love your explanation of crosslinking, I'm in training to paint cars and I never understood crosslinking in the paint until now Also, this would be perfect if used with a gel type material, for things like sword training and ballistics testing
I love science questions and explanations that u don’t think about everyday and now one feels like they gained a neuron ❤️✨ glad u popped on my feed, you have my subscription Steve
Well at first, i thought this video is gonna be about mental health, how to heal ourselves and things like that. It turned out to be about real self healing material, and the way Steve simply explains and provides scientific information about it was just... interesting :D the content was not what i expected it to be, but i watched this vid till the end and learn something new, thank you.
You don’t know how long I’ve been wondering why metals don’t self heal. I asked this to one of my metallurgy professors and he acted like I had asked a stupid question and blew me off. Thanks for finally scratching this irritating itch!
Sorry for the laziness of this post. Stolen from a stackexchange construction thread: By the way: The lack of oxidation in vacuum also has another interesting effect which could be either a blessing or a curse for space construction: It allows you to cold-weld. Pure, non-oxidized metals have an interesting property: When they touch, they stick and form a single piece. That means you could break a piece of metal into two, put the parts together again, and they would fuse without a trace. This effect is hard to reproduce on earth, because the moment you break a piece of metal, the exposed area comes into contact with oxygen and a nano-scale corrosion layer forms immediately which prevents cold-welding. But it works in an artificial pure vacuum environment. For space construction, this could be a blessing because it makes it much easier to put large structures together. Just move two girders together and they fuse the moment they touch. No welding, screws or bolts required. But it could also be a curse, because it is easy for accidental welding to occur. Any surfaces which are designed to touch and separate again (like mechanical gears or joints) need to be coated to avoid accidental cold-welding from happening. Exposing such parts to an oxygen-atmosphere for a short duration could be enough, though.
The one type of self-healing polymer that I'm really curious about is the type used in blood collection tubes. Most blood collection tubes have a rubber(?) cap at the top. To fill the tube, you pierce the cap with a needle. But when you take the needle out, it doesn't leave a hole! (Which is great, because you typically need to invert the tube after you draw blood and you don't want a contamination risk of any blood leaking out).
I really dont think this is some kind of self healing polymer. Probably just rubber, as you said. You make a hole, but you cant see because the walls get pushed in. This also seals it.
Extremely well put and interesting especially the outer space self healing metal I first came across self-healing tape many years ago. It was used by the GPO to waterproof underground cable connections. Amazing stuff.
I used some of this self-amalgamating repair tape on a damaged carpet cleaner hose and it worked really well. It's kind of spooky even how it works. It's so different from what we are used to that when you first start wrapping it around the hose you think there is no way this is going to hold. Yet, seconds later it's like having a brand new hose.
To think that I learned about oxidation but never asked the question and never thought it would be applicable... Very interesting video! Educational AND fun!
Thanks for explaining why things that are broken apart and not sticky don't self-heal/weld! I never knew that! And also that polymer seems really cool and probably has tons of applications :)
silicon is self adhering but doesn't really stick to anything else, and it does not oxidize quickly at normal temps, to have a decent oxidization speed requires at least 1000c and even then you are looking at an hour for very thin layers. Due to this its already made into self adhesive tape for fixing plumping leaks, this is likely just a silicon based tape shown in the video as it works exactly as shown.
I once cold-welded two sheets of microscope glass with some glycerine inbetween. I had a dropplet between the glass sheets and rubbed them against each other. My theory then was: At some point, the bonds of the glycerine or the glass should break and open the possibility of reconnecting both sides, as you have oxygen atoms with a molecular backbone. At some point this apparently happened. I never again could separate the two glass sheets.
This is very interesting! It's amazing how our atmosphere effects these things in these ways. It just feels like "common sense" that you cut something and it won't go back together. But the explanation as to why they don't go back together is actually much more scientific than one would first assume
These are the kind of people who give me hope for KZclip. Scientific content that is creative, informative, and actually gripping. Makes me wonder what my science teacher was doing 😂 Amazing job Steve!
Steve, when you join those two pieces together, is the reaction endo or exothermic by chance? You probably won't be able to feel it but a FLIR camera may show if it gets warm or cooler.
@PeteDiazDee some cars use a self healing material to cover the front of the car to protect from rock chips and what not. My understanding is that a bit of time in direct sunlight causes the material to self heal.
I just finished up my plastics engineering degree and I can spend some time to answer exactly what’s happening here in self-healing polymers. Buckle up this will be a long one. The information is from a polymer structures course I took and can be read about on page 233-234 of “Polymer Structure -> Physical Properties” textbook for University of Massachusetts Lowell written by Rudolph D. Deanin. The polymer I will use to explain the mechanism is styrene/butadiene/styrene sandwich block copolymer (SBS). To start, in polymers there are 3 kinds of microstructures we are currently confident about in multiphase systems (copolymers for intensive purposes). Spheres: When 2 polymers are not completely miscible, they tend to separate as discrete microparticles (domains) that are spherical. Spheres within spheres: Within some spherical domains, it has recently been discovered that when one polymer is present as relatively large spherical domains, much finer spheres of the other polymer in a copolymer have been found within the relatively large spherical domains. Rods: rigid rodlike structures dispersed throughout a continuous matrix. Spheres/rods/laminae: This is where I will explain self healing. In SBS, all of these types of domains have been observed according to the ratio of the two polymers. At an equal ratio of butadiene(B)/styrene(S) both phases form continuous laminae. At high B/S ratios with S spheres dispersed in a continuously rubbery matrix of B, the material is soft and rubbery and has low tensile modulus. With increasing S ratio, forming continuous rigid rods instead of spheres, these rigid rods greatly increase the modulus and strength of the rubbery matrix. When stretched, the S rods eventually break and disperse into spheres, even though they would have thermodynamically preferred to be rodlike at this B/S ratio. When allowed to stand for a long time at room temperature, they tend to equilibrate back into rods (aka “healing”) to reestablish thermodynamic equilibrium. The mechanical history (stress) contributes a significant factor in morphology (morphology basically =structure). Again in the same system, when the S rods have been tensile-shattered into spheres, the process of healing back into rods can be accelerated by annealing in an oven. Thus thermal history also contributes to morphology by helping establish thermodynamic equilibrium. And that’s all folks, hopefully some of you stuck around and maybe even learned something new. Feel free to reach out with any questions. Have a nice day.
@Dom when we think of “bonds being created” we have to be careful about what we specifically mean when we say that. We can create chain entanglements by adding heat or work and this will “fuse” 2 polymer substrates into a single mass. An example of this mechanism at work would be ultrasonic welding. Now, covalent C-C bonds in the main polymer chain are made during polymerization reactions. C-C bonds are extremely stable and are typically terminated with other extremely stable “end groups.” It is rare to see 2 polymer substrates form new bonds with each other, what’s really happening is that there is new attractive intermolecular forces forming. This being said, the mechanism at play in the video is on the scale of microstructure, not molecular structure. Microstructure is concerned with the way in which a defined molecular structure is oriented in space. The polymer I am talking about has a microstructure which changes due to thermal or mechanical history. The mechanism described for my polymer is one microstructure (rods) shattering due to mechanical stress into another microstructure (spheres). You can think of the spheres sort of like a liquid that will spread evenly over the local region of shattering. The liquid fills the void where the rods once were and flows nice and evenly over this region. Once heat is added at this stage, the “liquid” region where the rod shattering once happened turns back into rigid rods. It’s almost like it was heat cured. To your point on fatigue, this process I’m describing is actually adding fatigue to the material. When the shattering happens the physical polymer chain C-C backbone is being cut into smaller pieces. This lowers the molecular weight, and thus modulus is not conserved (it decreases). I hope this helps you somewhat piece this together, this is a lot of info to fit on a KZclip comment. The info is from a pretty advanced polymer structures course which required a lot of prior knowledge in chemistry, materials science, polymer science, and new polymer theories as bare-minimum prerequisites. It was almost unfair how hard that course was and I may have lost a few years due to it lol.
@Fire Flieer lolllll thanks I try to help out where I can so when there’s a video on advanced polymer science it’s kind of a once-in-a-lifetime chance to contribute.
@Jordan Cruikshank the golden pig would be an example of what’s called “elastic recovery.” Basically, some materials are designed to be deformed and recovered back to their original shape, most notably rubber bands, or elastics as some people may call them (go figure). Materials which don’t have a high degree of elastic recovery will instead “plastically deform.” This is a permanent slippage of polymer chains passed each other that cause the material to never recover. An example of this would be if you bend a piece of plastic enough so that it turns sort of white and it becomes permanently bent. This is plastic deformation.
@John Doe it is definitely possible. Many polymers are still very mobile (polymer chains will have enough heat energy to move freely) at low temperatures. This is characteristic of polymers with low transition temperatures. Imagine silly putty or something similar, at room temperature they are so mobile that they hardly need force/stress to be molded or even combined with another mass of putty.
Before silicon tape ham radio operators used to use unvulcanized natural rubber strips. When you hook up an RF cable to an RF connector outside you would wrap the connection in the rubber to make it water tight. The unvulcanized rubber was self fusing. Since it was rubber it would degrade in the elements (especially sunlight) after a while and you'd have to cut it off and do it again. You can still buy unvulcanized rubber sheets.
'Self-healing' (as a principle - I don't know the materials) is used in military aviation (vehicles?) in fuel-tanks for decades now (I guess that's why it is patented and not publicly available). Good video!
The “capsule” method is used in a lot of “Self Healing” tech. Mostly on “metals that can self heal” some batteries are now using Self Healing tech that uses capsules. I don’t think that’s what’s going on here either . But, either way I love this tech
Thank you for sharing this information. I am an HSC student and you make me realize how things I thought were not so important are actually important. 🙂
Self fusing silicone tape. It is a rubbery substance and have worked with it a lot it’s great for everything on a car (wiring looms mostly for me). It’s water proof, air tight, high temp proof, non conductive, high pressure resistance, oil proof and leaves no residue when cutting it. Perfect for wiring looms (near where oil can leak or near very hot components), coolant leaks, air leaks, oil leaks, wiring wrapping, waterproofing connectors. Good stuff a bit better then duct tape BUT doesn’t stick to any surface but itself which is a benefit but a pain to wrap in a circle around itself in a tight space.
I have this material as a screen protector on my phone. It was said to be what NASA use to protect the windows on spacecraft from small debris. Yes; it really does heal its self. I have had it for years, I've had nasty gashes taken out of it, and it returns to normal in time.
There is a phenomenon known as “ringing” (if memory serves. . .) where metal surfaces finished to a high level of flatness will stick together rather firmly. They have not “healed” into one piece, but it does take a fair amount of force to separate them. This may be “crosslinking ” as described here. I would expect that a polymerization reaction would be measurably stronger than crosslinking. A tensile strength test might shed some light, although getting a perfect heal across a cut would be difficult with this thin material.
Sir Patrick Stewart is responsible for my Earl Grey addiction. It's nice to see kindred spirits. (Also, the Captains series interviewing the actors was amazing)
Good, sir. Can I have a question, please? What if the two polymers are combine with each others but with the help of a glue? Is it gonna be stronger than the self-healing itself or is it gonna be weaker? I mean, because the glue itself has another substance that may effect the polymerization and crosslinking effect from the polymer itself. Thank you. Really appreciate your video. It's easy to understand this way.. 🙏
Loved that close up of the cut sodium. Never seen it depicted quite that way before. You could see the surface seem to bubble. What is that? Is that oxidation straight from the air? Or, could it relate to sodium pulling water out of the air? I'm tempted to say: "call in the slo mo guys", but what we may need is super macro guys who have the tech magic to overcome the sharpness robbing depth-of-field problems.
This is a very disingenuous video. He is trying to stretch apart the 'bonded' material. From 7:12 - 7:20 we clearly see the material being pinched and squeezed together, yet when he pulls at the seams it separates quiet easily. There is no molecular melding, no cellular cohesion, no welding at all PERIOD. But, but, Partial he pinched them together while they were stretched!!! Doesn't matter! If new molecular bonds were being created, stretching the material while the bonds were created would only serve to make them stronger when the material is relaxed.
Simple explaination: when you divide a thing, the structure beneath its skin will tear apart, the harder the material, the harder to break it - to divide it, because the structure is so stable and strict that a minor impact is not enough to separate it. However, with the same reason, it can also hard to put them back together because the tear apart structures will fix themselves, which means that if we broke 1 metal into 2 pieces, each pieces will reconstruct itself to stabilize its new structure, which made grouping them back again feels impossible.
A self healing phone screen or any device, car windshield, windows, would be interesting. I know something similiar to this polymer is used with medical bandages, it sticks togheter quite well.
It is so awesome that you anticipated the question of what would happen in a vacuum when discussing cutting a metal. It was the first thing that popped into my mind and I'm so thankful I didn't have to ask or look it up. Thanks!
@TissuePaper "During the tightening of the fastener, pressure builds between the contacting thread surfaces and breaks down the protective oxide coatings. With the absence of the oxide coating, the metal high points of the threads are exposed to one another, which increases friction. The combination of these two events can generate enough heat to fuse and seize the nut and bolt together." From fastenal, who the fuck uses wikipedia? Its commonly called cold welding, but that is an improper descriptor, friction welding is the mechanism of action that causes galling. Please guy, you think im talking about a wire or paper clip? Take a 1/4 inch thick steel pipe, you arent bending or breaking that, weld two sections together, you arent breaking that. If you "cold welded" those two pieces, you could easily snap it with very little effort. This is the point i am trying to get across, is it semantics? Sure, but why do you have a problem with being more accurate? Does my syntax hurt your pwecious wittle feeewings? Grow up sport, im doing you a favor.
@g00gleisgayerthanaids Galling absolutely isn't friction welding, no part of the fastener gets hot enough for friction welding when it's just being tightened. You can recite the Wikipedia page to me all you want. There are plenty of wires that I work with on a daily basis that I could easily pull apart with my bare hands. Does that mean that those continuous wires aren't actually continuous? Is a thin steel sheet not "continuous" by your definition because I could break it apart with my bare hands by bending it back and forth until it breaks? When did I ever say cold welding was a viable fabrication technique? Here's a hint: never. That doesn't mean that it doesn't happen spontaneously in many circumstances or "isn't real". You're being a condescending douche for no good reason.
@TissuePaper this is where youre wrong buck-o, on both accounts no less... As per your definition, the word implies a level of strength as does "one continuous piece" - when have you ever been able to just break a solid piece of metal with your bare hands? Galling forms as a result of friction, ie friction welding, which is absolutely not cold welding, boyo. Are you a welder? Or just some guy who has seen a few welding videos? A weld that breaks before the base metal isnt a weld, get it?
That sounds a bit like the question "If Teflon doesn't stick to anything, what holds it in the pan?" One thing that Teflon sticks to EXTREMELY well is more Teflon. So typically the pan will be roughened by sandblasting or acid etching, or something similar. The pits need undercuts so there are Velcro-like catch points. Then a thin layer of Teflon is sprayed on. It flows into the pits then cold-welds to itself in place forming a mechanical bond. Then as more layers are applied, they adhere well to the previous ones.
Hmm maybe I'm just unimaginative, but for practical application the only thing I'm coming up with is non-sticky Tapes. I'm interested to see what uses engineers and others come up with for this.
That material sounds like of like a nightmare to store because you have to make sure the sheets never ever touch each other or you potentially lose some of it. And imagine if someone drops alot of these where ever they are stored and they just start sticking to each other making just one giant sheet.
To float a ship on a gallon of water, you need to have a tub of the same contour as the ship's hull, so that they nest together like spoons. Then, you dump the gallon of water into the shell and place the ship into the tub. The water with fill the tub and create a thin layer break between both pieces! That's my idea, anyway.
In the metal case, I immidiately think how if we stick it as soon as it's cut to prevent oxidation happen. Then he talked about sticking it in vacuum. Well done
I've been searching for a video explaining how the self-healing cutting mats work but couldn't find any that had an explanation, just demonstration/testing. But this might be similar! :)
I've always wondered what makes something "self healing". Ever since I bought a self healing cutting board for crafts. I'm not sure if it's made of the same material. Thank you for another amazing video!
@Timothy Fish I vaguely recall some self-healing cutting boards that have micro-tubes of epoxy resin which ‘heal’ (fill) lacerations in the cutting surface, too.
This could be really good for gaskets for an engine or something similar where you could cut the gasket to avoid taking off parts and then stick it back together in place
Usually when you tie 2 individual items at the edge (let’s say trying to make a tower of spaghetti with no overlap) it becomes more unstable. Would this be the case with that plastic aswell? So if you have a 10cm overlap from the edge. Will it hold stronger than a 1cm overlap? Obviously I have no idea how this works so that’s why I’m wondering
@Jek I dont think that they're self healing at all even, cause when you bend the mat in the opposite way, you can see the creases and cut on the mat itself
I believe those operate by a different principle- Self healing cutting mats are basically super dense and short brushes, so when you cut into them your blade goes between the bristles. It's less that they self heal and more that they avoid being cut in the first place
I was wondering what this meant. Whenever I'm looking to buy a new cutting mat there's sometimes "self-healing" somewhere on the packaging...but I feel like I learned something different and beyond that and thought this video was super cool and informative!
Polymerization and cross-linking are not quite different in a Diels-Alder ring addition. These reactions may be reversible at room temperature, letting the material absorb and spread frontiers until equilibrium has been reestablished.
This should be the mandatory material for Vacuum Press Tables in wood shops. A single pin hole can ruin the vacuum seal and render the work useless as it wasn’t adequately clamped. If the pin hole can heal itself - that’s a serious game changer.
I clicked on it, bc I thought there will be advices on (mental) self healing. But I'm still here watching it, bc it's awesome. It was not the video I looked for, but the one I really needed 😂😂😂😂😂😂
4:41 Sorry to have to correct the science here, but I think you'll find that a Polymerization reaction is actually when you send two or more monsters from your hand or field to the graveyard in order to special summon a fusion monster that lists those monsters as fusion materials from your extra deck
Man I really want to see like an action figure made out of that stuff. Like maybe a wolverine one or something. Then you could be all like "He really heals!" and stuff.
I’m just curious... in all your video examples of the polymer sticking to itself, you showed this whilst handling the material with your bare hands. I was wondering if you could still test the polymers “healing” whilst removing the “human” element from the equation. I mention this as most humans bodies sit at an average of 37 C (or 97-98 F) and I’m curious if ‘heat’ is creating a reaction with the material. Maybe test it with cold hands after holding ice for a while, or with very thick rubber gloves that were left in a cool location.
I use a self-amalgating tape all the time at work and yes, you stretch it to activate it. It actually does a great job sticking to itself when you do it right. And to float a ship in a gallon of water you simply make the container the same shape as the ship so that a thin film of water floats the ship up to the draft height.
@Saltananda on the "where did the question come from" : I don't know either, but someone was wrong on the Internet (in a way that I knew was wrong, but had to think a bit to understand _why_ it was wrong).
@Saltananda Yeah, the "sealed air-tight" part would make it work. The seal would have to be incredibly inelastic, because otherwise, the pressure would bulge it out, and it doesn't take much to get enough bulge to fit a gallon of water along the whole waterline of the ship. At which point it becomes a somewhat academic point whether it is floating.
@Rich M Displacement really does mean you need to do it continuously: it's the mass of water you have to displace to someplace else, where that displaced water, wanting to flow back into the area now occupied by the ship, provides the force pushing the ship up. It's the potential energy of pushing the water away from a point below sea-level, causing the sea level to rise just a bit. It's downright minuscule, because the world oceans are huge. But the displaced water is now "higher" in the earth's gravitational potential, and the force is provided by it trying to flow back into the lower area it (or it's brethren sea-molecules, it's one big supportive family) previously occupied. It has no incentive to push back, if it has already found an even lower energy resting place outside the enclosing vessel.
@Curry Sama Well what I'm suggesting is more of a technicality, since it's "technically" not floating, yet still suspended by water. Quick question; where in the f*ck did this ship floating thing even come from? I don't see the original question anywhere? I just kinda jumped onboard.
It is not just the oxidation that is disabling the surface to stick together back again in a metal. If you introduce a heatsource then they form those chemical bonds back again. If you even press two different metals with two different melting points together can also link up. (The bond may not maynot be strong)
They use ultra high molecular weight polyethylene to cushion inside artificial joints. Awhile ago, they increased the strength of this polymer by gamma irradiation. The increased cross linkage significantly extended the life of these implants.
It’s sort of weird when you think about it, because a lot of these explanations of why things ‘stay broken’ boil down to: “when air touches a surface, it basically tells it, “you’re the outside of something now, and you shouldn’t easily join back up to anything else” It actually feels a little bit like “broken” status is actually an encoded property of objects when you think about it in this way
I just think it’s crazy since fusing any material by where is breaks means it will be weaker by default as it is fatigued.. but this polymer is quirky..
I love the way you explain like it's all common knowledge... Like obviously plastic wouldn't stick to itself because you just broke the perimeter of the mitochondria
I used this stuff for ultra-waterproofing a fiber optic connection. It worked super-well. Here in the US, you can find the stuff under the brand name of X-Treme silicone rubber self-fusing tape. Very useful stuff, and it really does fuse to itself; once it’s together it’s a solid mass that you have to cut to separate. It takes a second or two, but you need to make sure you put it where you want it!
"Two by two, hands of blue"
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Shiny
So what is the product and where can we buy it??? That's the most important link and it is missing.
@ken ezzell it would probably do so
I giveaway Beyblade
How do I get the polymer?
'I can't put metal back together.' then cuts metal and tries to put it back together. Scientific method at work. I love you Steve, make it tangible for us all.
We need to see every detail
Cold fusion
@Daniel Margita same man… it’s just too complex without it
You can, just melt it and freeze it
*Fire has left the chat*
“Cold welding” doesn’t actually have to happen in the vacuum of space. From experience I know that if you polish two quartz glass plates very flat and smooth and then stick them together, they will permanently bond as well. It’s pretty awesome!
That sounds insane!
but fo the case of metal it has to happen there, because like stated in the video, the metal will oxidise. still, does that mean that if fast enough, it is possible to rejoin the metal before oxidising?
@EternityForest Yes, metals *can* be amorphous - but only if you treat very specific alloys under very controlled conditions (see Wikipedia on "amorphous metal"). This will never happen "in nature". By what I read the first samples were produced in the 1960s.
@My Nung What about metallic glasses? Those are 1800s
I think the mechanism that puts the pieces back together is supramolecular interactions. The polimer chains are functionalized, at their ends there is an additional bonding, like a puzzle piece. So when you put them back together the puzzle pieces at the end of the polymer chains meet the other puzzle piece.
Can it be a 2d polymer?
Two polymers reacts not only on ends but on long parts of molecules
Unintended cold welding in space also happened on one of the Gemini missions, when they opened the hatch for a space walk. As the hatch hinges opened, the scraping between the two metal parts of each hinge cleared away the oxide layers enough so that the two parts of each hinge started to weld together in the open position, so when the walk was over they had a hard time closing the hatch.
Nope - it was a theory but not what actually happened.
Interesting!
Unfortunately though, a quick Google search led me to articles that say that while cold welding was originally thought to be the culprit, a SPRING that failed to compress was the real cause of the hatch not closing.
Still, it's an interesting phenomenon that I had no idea about.
Asking the question "Why DONT things heal or stick back" is such a great explainatory tool here! I wish some of my teachers had that way of explaining stuff back in the day.
This material repairs itself better than I can repair my life
Dam
Not me going through a break up and having a life crisis over a selfhealing plastic
buddy a broken window repairs itself better than i can repair my life
Ngl this self healing material reminds me of skin
True
A part of our group happens to be working on exactly such polymers, so I am somewhat familiar with the topic. There are 3 main ways to get self-healing polymers (sorted from least likely to most likely to explain this polymer):
1) Simply using a highly elastic resin, which causes stress to deform the material rather than break actual bonds. Over time and sometimes with a bit of heating the original shape is restored. An example of this being used is the "scratch shield", which is a highly elastic clearcoat used by Nissan to give their car finish the ability to heal moderate scratches by itself. Clearly your material has bonds fully broken upon tearing, so this is not the technique that's being used here.
2) Separated reservoirs of unpolymerized monomers and initiators/crosslinkers/catalysts. These can be either capsules or vascular systems spread evenly throughout the polymer. Upon injury, the monomer spills into the cracks and comes into contact with the initiator/crosslinker, causing it to polymerize and heal the injury. An early example of this is the use of Dicyclopentadiene monomer capsules that, when released after an injury, are polymerized by Grubb's Catalyst through an olefin metathesis reaction (doi.org/10.1038/35057232). The healing process uses up monomer and thus can only be performed a very limited number of times. In case of a full tear, the spilled monomer would polymerize on the loose end. Once fully polymerized joining the ends would no longer cause the polymer to heal. It seems unlikely that this technique is being used in your material.
3) Reversible bond breaking and formation (Also called "Intrinsic self-healing"). Polymers of this type have specific functional groups that can connect and disconnect with corresponding groups in a reversible manner. After a tear, rejoining the ends causes loose chains to reconnect to each other, healing the polymer. Closed chains can also be opened and then rejoined to form new links.
There are numerous ways to achieve this, some examples include:
3a) Reversible formation of covalent bonds, for example via Diels-Alder-/Retro-Diels-Alder reactions (DOI: 10.1126/science.1065879). Some chemical bonds can be reversibly broken and reformed. After joining the ends together, chains in both ends can break apart and recombine with chains from the other end, reestablishing covalent links. Usually, energetic triggers like heating or UV-light are required to facilitate the mending process. You did not use any such triggers, so this is probably not what you have.
3b) Reversible supramolecular bonding. I am quite certain that this is what makes your polymer mendable at room temperature. There are several interactions that can cause polymer chains to stick to each other without any covalent bonding (ionic attraction, coordinative bonds, hydrogen bonds and π-stacking interactions). These can sometimes also be broken and reestablished at room temperature.
You can imagine these supramolecular polymer networks to be like ball and stick magnet toys for children. Your sticks are short polymer chains with negative endgroups (ionic groups or chelating Lewis bases) and your balls are positive metal ions. The combination of both can form large networks of interconnected or entangled chains. The sticks can be flexible, but are not broken apart easily. However, the forces connecting balls and sticks are much weaker and so these connections can be rearranged with a relatively low activation energy, causing the material to stick to itself easily even after being fully disconnected for a long time.
Even lower activation energies would be needed for hydrogen bonding networks (replace opposite charges with hydrogen bond donors and acceptors, H-bonds are significantly weaker than ionic bonds). An example for this is published here (doi.org/10.1038/nature06669). I think self-assembly via hydrogen bonding is the most likely explanation for the behaviour of your polymer, though of course I can't say for sure.
An interesting example of an elastic polymer that sticks to itself but not other stuff is Parafilm, which is just a mixture of polyethylene and wax. It can't truly "self-heal", but it goes to show that even much simpler polymeric systems can show some of these properties.
I just wasted an hour of my time to write this... oh well.
“Oh well”
As so many other have pointed out, THANK YOU! For taking the time to write this all out! Such an interesting topic and sharing knowledge is never a waste! It's the most human of things to do. We are a curious species, hard wired to soak up knowledge and share it with others 😀
is he talking about the retro-encabulator?
I giveaway Beyblade
Such things you see in youtube comments..
I'm an injection molding process engineer and this is one of the most interesting things I've ever seen on the internet. Making flow fronts "re-bond" after they go around a core or other feature in an injection mold is a very difficult. We look at is a minimizing the weld line as you can't make these polymer chains truly re form. Typically this is done with greater injection speeds or higher temperatures. Albeit, greater injection speeds induce shear, therfore.. also heat related. Very very cool video. Thanks Steve!
@littletimmy I’m in my 20’s brother was 20 something when that happened, now he’s almost 40. What about you?
@LizardBreathsad to hear btw how old are u all
@littletimmy well he sliced his pinky almost off. Got surgery and then only that finger got stuck down like he’s making a fist. (If that makes sense) he let it be for a few years, went back in and they said there was nothing they could do besides chop it off, so they did. Now he has four fingers on one hand 😂
@LizardBreath how many fingers did ur brother lost btw 1 or 2? did he attach it together i mean is he alright
@littletimmy well, I’m not saying he’s dump😂 more so I mean, he probably has put in a lot of work over the years to learn all these things, but it’s not like you need a degree to do it. (So I don’t think he’s stupid, you just don’t have to be a genius) It’s just on the job learning for a long time. The machines are actually pretty complicated and some of them have like 40 buttons or touch screens. And you have to know how to download the info from the computer onto the machine, but I think that just takes knowing how to open files from a USB stick onto the machine. Also the molds in the plastic injection machines are anywhere from about $8,000 to like $200,000. It just depends on the size, how complicated it is, etc. so the fact that he’s the main engineer guy means he’s proved himself to the company with his knowledge and productivity! Also you have to be hella strong to move those things. One of my brothers lost a finger cause he wasn’t paying close enough attention when putting a mold in the machine 😂 I bet this guy is just your average machine mechanic/operator who has learned his specific trade well!
Dude I am actually blown away and baffled by the oxidation explanation. I just assumed that when you cut something (specifically metal) all the particles just naturally start to reorient to compensate for the new gap in space that is created and so when you would try to rejoin the two points they would just naturally start to repel because of the new orientation of the atoms would cause electrons from one piece to be repelling of the electrons on its counterpart and so on and so forth...
I really want to see two solid pieces of metal rejoin into a singular piece in space right now oh my God that sounds amazing
@Riccardo Boa Fair point. Without any research, my first guess would be that gold also oxidizes, just that it's not visible. After all, it's not completely inert. But I'll check, and edit in the answer below
Edit: It seems that it actually does cold-weld to an extent, and that most gold surfaces are just not clean enough to do it
@BlackHoleVortex what about gold tho
@Charlie Monroe Because this is a science video, it attracts a science based audience. The type of people who go out looking for this kind of information. Every comment section of every video is it’s own sort of bubble. A convention of people with a common interest of whatever the subject is about. Which is why it’s very interesting to read the comments of videos you know nothing about and be an observer to a bubble you’d never normally see
There is another issue with cutting a metal and sticking it back together no one is mentioning. The serration. It is easy to cut a polymer and have the two pieces touch evenly, since it is soft, but the same is not true for a metal.
@Carter Milan I mean, I don't remember any of it because high school was 10 years and lots of drugs ago.
There is this "self vulcanizing" (not sure if they're called that in english) rubber strips you can buy that does this too. They're been around for ages. Really cool stuff, I think it used to be popular for handles of different kinds before single piece stuff became cheap.
I just discovered this channel a few days ago, but it didn't take long to notice and appreciate the recurring appearance of Patrick Stewart. His appearance in the various contexts is, quite plainly, comedy gold. Thank you for mixing scientific learning with light hearted humor, it makes learning of new concepts that much more enjoyable.
hmm... gold cold welds
Edit: continued the video and you spoke of this...
It is very much possible to "cold weld" metals, but only if the parts are completely flush and without any oxidation.
Depending on the success of the cut, the material will be just as strong as if it was never cut in the first place.
Dad went to a metalworking school and had his practice at a forge. He saw the process and even though cold welding is never perfect, I found the idea bonkers and fascinating.
At Uni I did a project on self-healing materials, taking inspiration from Mussels. We were trying to replicate the self-healing properties by making an organometallic aerogel. Was really interesting but the scope ended up becoming multiple PhD thesises (no idea how it ended, if it has yet)
@So Del solo any information?
Damn, you almost kickstarted a possible way for humans to regrow limbs and stuff.
But were can we buy this polymer
Can you send me any more information on this project?
You got me with your little Patrick Stewart altar 😂
Beautifully explained and incredibly entertaining, as usual, Steve!
@Кочетков Іван Вікторович he doesn't have a little Patrick Stewart altar >.>
@MrM6d You don't have little Patrick Stewart altar, do you?
But just a hedge bit creepy too.
I may have experienced a self-glueing sticker once. This vid left me thinking if it was something similar. It was in an airport, a self-service baggage drop-off station automatically printed the long paper strip that you attach as a tag to your bag, with its identifying information. I remember the tag had one printed paper side, and another plasticky side that surprisingly didn't stick to your hands but glued firmly to itself when you bent it around the handle of your bag and made it touch itself. I remember being baffled that it didn't feel like the familiar adhesive side of a sticker at all. It didn't stick to the handle of your bag either which made it really convenient to detach later without leaving residue. Has ayone else ever come across this?
I used to always ask myself as a kid why cut things can't be put back together. Then I graduated at Chemistry but never realized how obvious it is LOL
Prob because I work with water so no time to think about materials anymore. Thank you for pointing it out!
This self-healing polymer is indeed very interesting
Fantastic explaination, even if you aren't sure. I was trying figure out why I'm able to puncture a film on a bottle of insulin so many times without destroying it.
Easy to understand and funny, too. I'm a fan. Thanks!
"Cold welding" totally blew my mind, and learning about it made it much easier to understand how a similar effect is possible here on earth. Awesome video!
@Elisha Caez imagine how it doesn't work
they actually do it with copper, but it requires very high pressures
Imagine how we could make stuff faster with these new findings
@Yksha Yllen
Your english is excellent for an infant!
@YamaNeko it really doesn't work that way
they used to think metals would wildly stick to each other in space but it's really not the case
unless you manufactured it in space it's already covered in oxide
We routinely do touch welding of copper on earth but you have to press it together *REALLY* hard
etc
@Yksha Yllen its cold fusión
This man literally answered every question that popped into my mind as they popped up.
I love your explanation of crosslinking, I'm in training to paint cars and I never understood crosslinking in the paint until now
Also, this would be perfect if used with a gel type material, for things like sword training and ballistics testing
Where were you when I was failing high school chemistry?! You explained things much better than my teacher ever did.
I love science questions and explanations that u don’t think about everyday and now one feels like they gained a neuron ❤️✨ glad u popped on my feed, you have my subscription Steve
Well at first, i thought this video is gonna be about mental health, how to heal ourselves and things like that. It turned out to be about real self healing material, and the way Steve simply explains and provides scientific information about it was just... interesting :D the content was not what i expected it to be, but i watched this vid till the end and learn something new, thank you.
You don’t know how long I’ve been wondering why metals don’t self heal. I asked this to one of my metallurgy professors and he acted like I had asked a stupid question and blew me off. Thanks for finally scratching this irritating itch!
Hey bro, sorry about that but gold particles can heal themselves
Sorry for the laziness of this post. Stolen from a stackexchange construction thread: By the way: The lack of oxidation in vacuum also has another interesting effect which could be either a blessing or a curse for space construction: It allows you to cold-weld. Pure, non-oxidized metals have an interesting property: When they touch, they stick and form a single piece. That means you could break a piece of metal into two, put the parts together again, and they would fuse without a trace. This effect is hard to reproduce on earth, because the moment you break a piece of metal, the exposed area comes into contact with oxygen and a nano-scale corrosion layer forms immediately which prevents cold-welding. But it works in an artificial pure vacuum environment.
For space construction, this could be a blessing because it makes it much easier to put large structures together. Just move two girders together and they fuse the moment they touch. No welding, screws or bolts required. But it could also be a curse, because it is easy for accidental welding to occur. Any surfaces which are designed to touch and separate again (like mechanical gears or joints) need to be coated to avoid accidental cold-welding from happening. Exposing such parts to an oxygen-atmosphere for a short duration could be enough, though.
There are actually videos of microscopic gold wires self welding in microprocessor production or something to that effect.
The one type of self-healing polymer that I'm really curious about is the type used in blood collection tubes. Most blood collection tubes have a rubber(?) cap at the top. To fill the tube, you pierce the cap with a needle. But when you take the needle out, it doesn't leave a hole! (Which is great, because you typically need to invert the tube after you draw blood and you don't want a contamination risk of any blood leaking out).
This is the same for micro mushroom grow bags. The injection port reseals but not in the sense you think. It just expands and the port closes up.
Thats just elastic
I really dont think this is some kind of self healing polymer. Probably just rubber, as you said. You make a hole, but you cant see because the walls get pushed in. This also seals it.
I use insulin vials and wondered the same thing sometimes.
Extremely well put and interesting especially the outer space self healing metal
I first came across self-healing tape many years ago. It was used by the GPO to waterproof underground cable connections. Amazing stuff.
I used some of this self-amalgamating repair tape on a damaged carpet cleaner hose and it worked really well. It's kind of spooky even how it works. It's so different from what we are used to that when you first start wrapping it around the hose you think there is no way this is going to hold. Yet, seconds later it's like having a brand new hose.
To think that I learned about oxidation but never asked the question and never thought it would be applicable... Very interesting video! Educational AND fun!
This teaches better than the chemistry class in my school
Thanks for explaining why things that are broken apart and not sticky don't self-heal/weld! I never knew that!
And also that polymer seems really cool and probably has tons of applications :)
@dsp4 I know all plastics are polymers, that's why I said "that" polymer.
Polymer sure has a ton of uses. All plastics are polymers, and even DNA is a polymer.
@navster10 trust me if you’re boning as often as I am you’d needn’t have a purpose for getting it off in the first place
silicon is self adhering but doesn't really stick to anything else, and it does not oxidize quickly at normal temps, to have a decent oxidization speed requires at least 1000c and even then you are looking at an hour for very thin layers.
Due to this its already made into self adhesive tape for fixing plumping leaks, this is likely just a silicon based tape shown in the video as it works exactly as shown.
Ya, its pretty much what Alien Tape is... In the video, it looks like Alien Shield (another product from the same manufacturer)
I once cold-welded two sheets of microscope glass with some glycerine inbetween. I had a dropplet between the glass sheets and rubbed them against each other. My theory then was: At some point, the bonds of the glycerine or the glass should break and open the possibility of reconnecting both sides, as you have oxygen atoms with a molecular backbone. At some point this apparently happened. I never again could separate the two glass sheets.
I'd love to know if this is the same tech they use in self-healing sewing cutting mats! They're pretty cool!
This is very interesting! It's amazing how our atmosphere effects these things in these ways.
It just feels like "common sense" that you cut something and it won't go back together. But the explanation as to why they don't go back together is actually much more scientific than one would first assume
Nearly every explanation for a physical phenomena is this complex
How did I go from emotional work to fully engrossed in this fusion video. Thank you 😊
These are the kind of people who give me hope for KZclip. Scientific content that is creative, informative, and actually gripping. Makes me wonder what my science teacher was doing 😂
Amazing job Steve!
Steve, when you join those two pieces together, is the reaction endo or exothermic by chance? You probably won't be able to feel it but a FLIR camera may show if it gets warm or cooler.
Can you buy this anywhere?
@PeteDiazDee some cars use a self healing material to cover the front of the car to protect from rock chips and what not. My understanding is that a bit of time in direct sunlight causes the material to self heal.
Nerds
Making bonds is exothermic iirc
I just finished up my plastics engineering degree and I can spend some time to answer exactly what’s happening here in self-healing polymers. Buckle up this will be a long one. The information is from a polymer structures course I took and can be read about on page 233-234 of “Polymer Structure -> Physical Properties” textbook for University of Massachusetts Lowell written by Rudolph D. Deanin.
The polymer I will use to explain the mechanism is styrene/butadiene/styrene sandwich block copolymer (SBS). To start, in polymers there are 3 kinds of microstructures we are currently confident about in multiphase systems (copolymers for intensive purposes).
Spheres: When 2 polymers are not completely miscible, they tend to separate as discrete microparticles (domains) that are spherical.
Spheres within spheres: Within some spherical domains, it has recently been discovered that when one polymer is present as relatively large spherical domains, much finer spheres of the other polymer in a copolymer have been found within the relatively large spherical domains.
Rods: rigid rodlike structures dispersed throughout a continuous matrix.
Spheres/rods/laminae: This is where I will explain self healing. In SBS, all of these types of domains have been observed according to the ratio of the two polymers. At an equal ratio of butadiene(B)/styrene(S) both phases form continuous laminae. At high B/S ratios with S spheres dispersed in a continuously rubbery matrix of B, the material is soft and rubbery and has low tensile modulus. With increasing S ratio, forming continuous rigid rods instead of spheres, these rigid rods greatly increase the modulus and strength of the rubbery matrix. When stretched, the S rods eventually break and disperse into spheres, even though they would have thermodynamically preferred to be rodlike at this B/S ratio. When allowed to stand for a long time at room temperature, they tend to equilibrate back into rods (aka “healing”) to reestablish thermodynamic equilibrium. The mechanical history (stress) contributes a significant factor in morphology (morphology basically =structure).
Again in the same system, when the S rods have been tensile-shattered into spheres, the process of healing back into rods can be accelerated by annealing in an oven. Thus thermal history also contributes to morphology by helping establish thermodynamic equilibrium.
And that’s all folks, hopefully some of you stuck around and maybe even learned something new. Feel free to reach out with any questions. Have a nice day.
@Dom when we think of “bonds being created” we have to be careful about what we specifically mean when we say that. We can create chain entanglements by adding heat or work and this will “fuse” 2 polymer substrates into a single mass. An example of this mechanism at work would be ultrasonic welding. Now, covalent C-C bonds in the main polymer chain are made during polymerization reactions. C-C bonds are extremely stable and are typically terminated with other extremely stable “end groups.” It is rare to see 2 polymer substrates form new bonds with each other, what’s really happening is that there is new attractive intermolecular forces forming. This being said, the mechanism at play in the video is on the scale of microstructure, not molecular structure. Microstructure is concerned with the way in which a defined molecular structure is oriented in space. The polymer I am talking about has a microstructure which changes due to thermal or mechanical history. The mechanism described for my polymer is one microstructure (rods) shattering due to mechanical stress into another microstructure (spheres). You can think of the spheres sort of like a liquid that will spread evenly over the local region of shattering. The liquid fills the void where the rods once were and flows nice and evenly over this region. Once heat is added at this stage, the “liquid” region where the rod shattering once happened turns back into rigid rods. It’s almost like it was heat cured. To your point on fatigue, this process I’m describing is actually adding fatigue to the material. When the shattering happens the physical polymer chain C-C backbone is being cut into smaller pieces. This lowers the molecular weight, and thus modulus is not conserved (it decreases). I hope this helps you somewhat piece this together, this is a lot of info to fit on a KZclip comment. The info is from a pretty advanced polymer structures course which required a lot of prior knowledge in chemistry, materials science, polymer science, and new polymer theories as bare-minimum prerequisites. It was almost unfair how hard that course was and I may have lost a few years due to it lol.
@Fire Flieer lolllll thanks I try to help out where I can so when there’s a video on advanced polymer science it’s kind of a once-in-a-lifetime chance to contribute.
@0.5 degrees you’re welcome.
@Jordan Cruikshank the golden pig would be an example of what’s called “elastic recovery.” Basically, some materials are designed to be deformed and recovered back to their original shape, most notably rubber bands, or elastics as some people may call them (go figure). Materials which don’t have a high degree of elastic recovery will instead “plastically deform.” This is a permanent slippage of polymer chains passed each other that cause the material to never recover. An example of this would be if you bend a piece of plastic enough so that it turns sort of white and it becomes permanently bent. This is plastic deformation.
@John Doe it is definitely possible. Many polymers are still very mobile (polymer chains will have enough heat energy to move freely) at low temperatures. This is characteristic of polymers with low transition temperatures. Imagine silly putty or something similar, at room temperature they are so mobile that they hardly need force/stress to be molded or even combined with another mass of putty.
Before silicon tape ham radio operators used to use unvulcanized natural rubber strips. When you hook up an RF cable to an RF connector outside you would wrap the connection in the rubber to make it water tight. The unvulcanized rubber was self fusing. Since it was rubber it would degrade in the elements (especially sunlight) after a while and you'd have to cut it off and do it again. You can still buy unvulcanized rubber sheets.
'Self-healing' (as a principle - I don't know the materials) is used in military aviation (vehicles?) in fuel-tanks for decades now (I guess that's why it is patented and not publicly available). Good video!
The “capsule” method is used in a lot of “Self Healing” tech. Mostly on “metals that can self heal” some batteries are now using Self Healing tech that uses capsules. I don’t think that’s what’s going on here either . But, either way I love this tech
Thank you for sharing this information. I am an HSC student and you make me realize how things I thought were not so important are actually important. 🙂
Love your humor of putting up a Patrick Stewart (fixed) shrine. You are fantastic. Thanks for regularly making us smarter.
Her buns are the best
@J Smith Oh my. Looks like I had the wrong spelling, haha.
PRAISE ALMIGHTY GRAND MASTER PAT STU AYAYAYAYAYA
@J Smith Charles Xavier
Who is Patrick Stuart?
Self fusing silicone tape. It is a rubbery substance and have worked with it a lot it’s great for everything on a car (wiring looms mostly for me). It’s water proof, air tight, high temp proof, non conductive, high pressure resistance, oil proof and leaves no residue when cutting it. Perfect for wiring looms (near where oil can leak or near very hot components), coolant leaks, air leaks, oil leaks, wiring wrapping, waterproofing connectors. Good stuff a bit better then duct tape BUT doesn’t stick to any surface but itself which is a benefit but a pain to wrap in a circle around itself in a tight space.
Very informative video Steve. Wish my soul self-healed like that.
Aww😭
Love the Sir Patrick shrine, so appropriate to have one.
I have this material as a screen protector on my phone. It was said to be what NASA use to protect the windows on spacecraft from small debris.
Yes; it really does heal its self. I have had it for years, I've had nasty gashes taken out of it, and it returns to normal in time.
This is insane
And also thank you for explaining it really simply for all the non scientist 🥼 like me
🙏🏻
There is a phenomenon known as “ringing” (if memory serves. . .) where metal surfaces finished to a high level of flatness will stick together rather firmly. They have not “healed” into one piece, but it does take a fair amount of force to separate them.
This may be “crosslinking ” as described here. I would expect that a polymerization reaction would be measurably stronger than crosslinking. A tensile strength test might shed some light, although getting a perfect heal across a cut would be difficult with this thin material.
You're obsession with Patrick Stewart is so... understandable and relatable. Thank you for sharing this passion with the world!
Sir Patrick Stewart's favorite cartoon is Beavis and Butt-Head.
Only if you pretend the Picard series isn't real.
Sir Patrick Stewart is responsible for my Earl Grey addiction. It's nice to see kindred spirits. (Also, the Captains series interviewing the actors was amazing)
It's more like a passion for Jean-Luc Picard
Good, sir. Can I have a question, please? What if the two polymers are combine with each others but with the help of a glue? Is it gonna be stronger than the self-healing itself or is it gonna be weaker? I mean, because the glue itself has another substance that may effect the polymerization and crosslinking effect from the polymer itself. Thank you. Really appreciate your video. It's easy to understand this way.. 🙏
Amazing video! Really interesting to learn about. I was wondering if you could do some more research on this.
Props for the cameraman for going monucle size and recording the split
This single video is worth more than every chemistry lessons i have had this year added together
Loved that close up of the cut sodium. Never seen it depicted quite that way before. You could see the surface seem to bubble. What is that? Is that oxidation straight from the air? Or, could it relate to sodium pulling water out of the air? I'm tempted to say: "call in the slo mo guys", but what we may need is super macro guys who have the tech magic to overcome the sharpness robbing depth-of-field problems.
So is this like an atom-level Velcro?
Bro!
Exactly my thought!!!
well you can’t really take this apart, can you?
This is a very disingenuous video. He is trying to stretch apart the 'bonded' material. From 7:12 - 7:20 we clearly see the material being pinched and squeezed together, yet when he pulls at the seams it separates quiet easily. There is no molecular melding, no cellular cohesion, no welding at all PERIOD. But, but, Partial he pinched them together while they were stretched!!! Doesn't matter! If new molecular bonds were being created, stretching the material while the bonds were created would only serve to make them stronger when the material is relaxed.
no
Simple explaination: when you divide a thing, the structure beneath its skin will tear apart, the harder the material, the harder to break it - to divide it, because the structure is so stable and strict that a minor impact is not enough to separate it. However, with the same reason, it can also hard to put them back together because the tear apart structures will fix themselves, which means that if we broke 1 metal into 2 pieces, each pieces will reconstruct itself to stabilize its new structure, which made grouping them back again feels impossible.
It’s like when storing latex you gotta powder it so they don’t fuse. But at an expedited rate. Pretty much immediate. Amazing.
As a physics student I beg you to do more awesome videos like this ❤️❤️❤️
1:26 You can fuse two pieces of metal together by using pressure. And Guage Blocks stick together quite well.
A self healing phone screen or any device, car windshield, windows, would be interesting. I know something similiar to this polymer is used with medical bandages, it sticks togheter quite well.
It is so awesome that you anticipated the question of what would happen in a vacuum when discussing cutting a metal.
It was the first thing that popped into my mind and I'm so thankful I didn't have to ask or look it up.
Thanks!
@TissuePaper "During the tightening of the
fastener, pressure builds between the contacting thread surfaces and breaks down the protective oxide
coatings. With the absence of the oxide coating, the metal high points of the threads are exposed to one
another, which increases friction. The combination of these two events can generate enough heat to fuse
and seize the nut and bolt together." From fastenal, who the fuck uses wikipedia?
Its commonly called cold welding, but that is an improper descriptor, friction welding is the mechanism of action that causes galling.
Please guy, you think im talking about a wire or paper clip? Take a 1/4 inch thick steel pipe, you arent bending or breaking that, weld two sections together, you arent breaking that. If you "cold welded" those two pieces, you could easily snap it with very little effort. This is the point i am trying to get across, is it semantics? Sure, but why do you have a problem with being more accurate? Does my syntax hurt your pwecious wittle feeewings? Grow up sport, im doing you a favor.
@g00gleisgayerthanaids Galling absolutely isn't friction welding, no part of the fastener gets hot enough for friction welding when it's just being tightened. You can recite the Wikipedia page to me all you want.
There are plenty of wires that I work with on a daily basis that I could easily pull apart with my bare hands. Does that mean that those continuous wires aren't actually continuous? Is a thin steel sheet not "continuous" by your definition because I could break it apart with my bare hands by bending it back and forth until it breaks?
When did I ever say cold welding was a viable fabrication technique? Here's a hint: never. That doesn't mean that it doesn't happen spontaneously in many circumstances or "isn't real". You're being a condescending douche for no good reason.
@TissuePaper this is where youre wrong buck-o, on both accounts no less...
As per your definition, the word implies a level of strength as does "one continuous piece" - when have you ever been able to just break a solid piece of metal with your bare hands?
Galling forms as a result of friction, ie friction welding, which is absolutely not cold welding, boyo.
Are you a welder? Or just some guy who has seen a few welding videos?
A weld that breaks before the base metal isnt a weld, get it?
Tbh , your wonderful explanation changed my perspective towards interaction among molecules while in a giant piece!
That sounds a bit like the question "If Teflon doesn't stick to anything, what holds it in the pan?"
One thing that Teflon sticks to EXTREMELY well is more Teflon. So typically the pan will be roughened by sandblasting or acid etching, or something similar. The pits need undercuts so there are Velcro-like catch points. Then a thin layer of Teflon is sprayed on. It flows into the pits then cold-welds to itself in place forming a mechanical bond. Then as more layers are applied, they adhere well to the previous ones.
Hmm maybe I'm just unimaginative, but for practical application the only thing I'm coming up with is non-sticky Tapes.
I'm interested to see what uses engineers and others come up with for this.
That material sounds like of like a nightmare to store because you have to make sure the sheets never ever touch each other or you potentially lose some of it. And imagine if someone drops alot of these where ever they are stored and they just start sticking to each other making just one giant sheet.
I love that you actually play devils advocate and answer any questions I had
You did a really good job with the visuals and explaining this
To float a ship on a gallon of water, you need to have a tub of the same contour as the ship's hull, so that they nest together like spoons. Then, you dump the gallon of water into the shell and place the ship into the tub. The water with fill the tub and create a thin layer break between both pieces! That's my idea, anyway.
In the metal case, I immidiately think how if we stick it as soon as it's cut to prevent oxidation happen. Then he talked about sticking it in vacuum. Well done
I've been searching for a video explaining how the self-healing cutting mats work but couldn't find any that had an explanation, just demonstration/testing. But this might be similar! :)
In the navy we have this exact thing. We call it "Cherry Tape" it is used to wrap around electronic connectors .
I've always wondered what makes something "self healing". Ever since I bought a self healing cutting board for crafts. I'm not sure if it's made of the same material. Thank you for another amazing video!
So basically jusr beat up the board and let it melt a little?
@Jasper imagine the poisons in this product.
@Timothy Fish i knew it wasnt self healing when i saw the one on AvEs bench
@Timothy Fish I vaguely recall some self-healing cutting boards that have micro-tubes of epoxy resin which ‘heal’ (fill) lacerations in the cutting surface, too.
This could be really good for gaskets for an engine or something similar where you could cut the gasket to avoid taking off parts and then stick it back together in place
Science At This Point Is Just Plain Fascinating, props to the scientists who do all these stuff
What did you use for the clear sheets of self healing polymer?
This is good,for healing. Doctors need to use this in their advantage to heal founds or arteries.
Usually when you tie 2 individual items at the edge (let’s say trying to make a tower of spaghetti with no overlap) it becomes more unstable. Would this be the case with that plastic aswell?
So if you have a 10cm overlap from the edge. Will it hold stronger than a 1cm overlap? Obviously I have no idea how this works so that’s why I’m wondering
This is really interesting, I have "self healing" cutting mats for cutting fabric on and always wondered how they were self healing
Majin Buu paper
self healing mats dont actual heal, theyre just dense plastic that when cut it shouldnt leave ridges but they usually do...
@Jek thats cool, i want one
@Jek I dont think that they're self healing at all even, cause when you bend the mat in the opposite way, you can see the creases and cut on the mat itself
I believe those operate by a different principle- Self healing cutting mats are basically super dense and short brushes, so when you cut into them your blade goes between the bristles. It's less that they self heal and more that they avoid being cut in the first place
I was wondering what this meant. Whenever I'm looking to buy a new cutting mat there's sometimes "self-healing" somewhere on the packaging...but I feel like I learned something different and beyond that and thought this video was super cool and informative!
Polymerization and cross-linking are not quite different in a Diels-Alder ring addition. These reactions may be reversible at room temperature, letting the material absorb and spread frontiers until equilibrium has been reestablished.
This should be the mandatory material for Vacuum Press Tables in wood shops.
A single pin hole can ruin the vacuum seal and render the work useless as it wasn’t adequately clamped.
If the pin hole can heal itself - that’s a serious game changer.
When scientists manage to transfer a human consciousness into the body of an AI robot, this is the kind of material I want
I clicked on it, bc I thought there will be advices on (mental) self healing. But I'm still here watching it, bc it's awesome. It was not the video I looked for, but the one I really needed 😂😂😂😂😂😂
4:41 Sorry to have to correct the science here, but I think you'll find that a Polymerization reaction is actually when you send two or more monsters from your hand or field to the graveyard in order to special summon a fusion monster that lists those monsters as fusion materials from your extra deck
You’re nuts!
Don't say sorry when correcting information, especially in science! It only helps people!
Lol
@Activated Almond clearly you’re just seeking for attention💀
@Jeff Hardyz You thought that was funny, did you Jeff? You think this is some kind of joke?
Man I really want to see like an action figure made out of that stuff. Like maybe a wolverine one or something. Then you could be all like "He really heals!" and stuff.
I’m just curious... in all your video examples of the polymer sticking to itself, you showed this whilst handling the material with your bare hands. I was wondering if you could still test the polymers “healing” whilst removing the “human” element from the equation. I mention this as most humans bodies sit at an average of 37 C (or 97-98 F) and I’m curious if ‘heat’ is creating a reaction with the material. Maybe test it with cold hands after holding ice for a while, or with very thick rubber gloves that were left in a cool location.
Thank you, this feeds my never-ending hunger of learning something new :)
These guy excudes such a positive energy that they tends to lift spirits ❤️,
"My heart will never shattered in pieces because its made out of self healing polymer"
I use a self-amalgating tape all the time at work and yes, you stretch it to activate it. It actually does a great job sticking to itself when you do it right. And to float a ship in a gallon of water you simply make the container the same shape as the ship so that a thin film of water floats the ship up to the draft height.
@Validole I don't even know why I got so into it, at the end of the day it's still a statistically impossible feat.
@Saltananda on the "where did the question come from" : I don't know either, but someone was wrong on the Internet (in a way that I knew was wrong, but had to think a bit to understand _why_ it was wrong).
@Saltananda Yeah, the "sealed air-tight" part would make it work. The seal would have to be incredibly inelastic, because otherwise, the pressure would bulge it out, and it doesn't take much to get enough bulge to fit a gallon of water along the whole waterline of the ship. At which point it becomes a somewhat academic point whether it is floating.
@Rich M Displacement really does mean you need to do it continuously: it's the mass of water you have to displace to someplace else, where that displaced water, wanting to flow back into the area now occupied by the ship, provides the force pushing the ship up. It's the potential energy of pushing the water away from a point below sea-level, causing the sea level to rise just a bit. It's downright minuscule, because the world oceans are huge. But the displaced water is now "higher" in the earth's gravitational potential, and the force is provided by it trying to flow back into the lower area it (or it's brethren sea-molecules, it's one big supportive family) previously occupied. It has no incentive to push back, if it has already found an even lower energy resting place outside the enclosing vessel.
@Curry Sama Well what I'm suggesting is more of a technicality, since it's "technically" not floating, yet still suspended by water.
Quick question; where in the f*ck did this ship floating thing even come from? I don't see the original question anywhere? I just kinda jumped onboard.
It is not just the oxidation that is disabling the surface to stick together back again in a metal. If you introduce a heatsource then they form those chemical bonds back again. If you even press two different metals with two different melting points together can also link up. (The bond
may not maynot be strong)
They use ultra high molecular weight polyethylene to cushion inside artificial joints. Awhile ago, they increased the strength of this polymer by gamma irradiation. The increased cross linkage significantly extended the life of these implants.
It’s sort of weird when you think about it, because a lot of these explanations of why things ‘stay broken’ boil down to: “when air touches a surface, it basically tells it, “you’re the outside of something now, and you shouldn’t easily join back up to anything else”
It actually feels a little bit like “broken” status is actually an encoded property of objects when you think about it in this way
I just think it’s crazy since fusing any material by where is breaks means it will be weaker by default as it is fatigued.. but this polymer is quirky..
I love the way you explain like it's all common knowledge... Like obviously plastic wouldn't stick to itself because you just broke the perimeter of the mitochondria
I used this stuff for ultra-waterproofing a fiber optic connection. It worked super-well. Here in the US, you can find the stuff under the brand name of X-Treme silicone rubber self-fusing tape. Very useful stuff, and it really does fuse to itself; once it’s together it’s a solid mass that you have to cut to separate. It takes a second or two, but you need to make sure you put it where you want it!
@Baden West nah, self amalgamating tape is different.
@Dylan Pix that is the 'self amalgamating' tape he mentions at the end which is similiar but not quite as good as the one he is using in the video.
@ᛋᛒᛖᚱᚫᛞᚻᛏ thank you good sir.
@tasnimul sarwar will do.
It's called SOS Silicone Tape here in Australia if anyone is looking for it.
You should look into supramolecular chemistry if you find self healing an interesting topic! Explains the principles
We’re reaching the dark age of technology and I’m all for it
Very interesting! What is the polymer the strip is made of?