TechStuff Plays with Carbon Nanotubes

the element that you are in fact old. Yes, that is the best thing about her, Thank you so much. Moving on to something that's not old, it's relatively new. Do you like that? Yeah? That was That was a good good transition when you point them out there, terrible anyway a plus making it bad. Thank you, car and nanotubes.

That's what we wanted to talk about. Yeah, and for at first we thought that we would talk a little bit about why carbon is cool because um so so it's it's an element of incredibly uh popular element here on the planet Earth and is way up there it is. It is in fact the fourth most abundant element in the universe by mass um, after hydrogen, helium and oxygen and the second most abundant element in the human body. Yeah. Yeah,

we are what is known as carbon based life forms. Yeah. Um. And all of this is made possible because carbon atoms are these niffy little hexagons made with six electrons um. They they bond very easily with one another. Actually, if they bond in a lattice structure, which is a hexagonal structure, you have a sheet of that. So you've got a whole bunch of carbon atoms that are molecularly bonded to one another in this hexagon pattern. Here in the South.

I like to call it chicken wire. Anyone who anyone who lives in any sort of rural environment who has seen chicken wire, that's kind of what a sheet of these carbon atoms in molecular structure look like. We call

that sheet graphing. So let's say you've got this sheet of graphing, which is essentially two dimensional, right, because adams don't really have a lot of thickness to them, so they are you're you're talking about with and length, you're not talking about depth, And I mean that's you know, one atom thick that's thin enough to call it two dimensional. Absolutely, So you've got the sheet of graphing. Let's say, then you roll the graphing into a I don't know, burrito

like structure. It's not necessarily going to be filled with cheesy beanie goodness. You know, I kind of want a carbon nano to burrito. Now. I am craving burritos like you wouldn't believe. But but no, No, that's what we call a carbon nanotube. You take that sheet of graphing, this this hexagonal molecular structure of carbon, and this is just carbon you and you roll it up and that's

a carbon nanotube. But you know, carbon is kind of an amazing thing anyway, because carbon can take on so many different forms, right right, yeah, I mean it's what diamonds and graphite are both made of, and it's totally different a little little bit. I mean, you know that's you've got. You've got the hardest substance, the hardst natural substance known on Earth, right, and then you've got what you put in pencils essentially, So yeah, something soft enough

that paper is paper, paper is its match? Right yeah? Yeah. So so this is something that we call allotropes. Now, an allotrope. You know, you're like, what the heck is that? Well, if you if you've studied chemistry, you know. So I apologize to all the chemists out there who are screaming at me because I'm assuming they don't know what an allotroples. It's okay, I know. You know. Also, y'all can go just get a soda for the next about So, an allotrope is any of two or more physical forms in

which an element can exist. So you we have these elements that can exist in different physical forms, and carbon is a perfect example. Lauren was just pointing out diamond versus versus a graph fite. So you've got these two very different kinds of forms, but they're still the same basic element. Uh well, carbon nanotubes are very similar in

that way. We'll talk a bit more about the different properties that carbon nano tubes can have and why they can have different properties, but we need to lead up to that. Yeah, yeah, yeah, Well this entire carbon nanotube business was discovered in by Sumio Ijima, I believe is the way that you pronounce it. Um. Apologies to my Japanese teacher. Um. Although research into into creating these sheets

of graphine stretches back into the nineteen fifties. Um. And all of these are they're they're actually two processes for making them. One of them I'm not extremely familiar with, and it's written all the way down at the bottom of my notes, So we're going to cover that one later. That's a wet application. The general way of making card nanotubes is a dry application, and you m thermally strip

carbon atoms off of carbon bearing compounds. Wow, that sounds complicated, or at least violent and violent violent at an atomic level.

That is extremely violent. Yeah, and so this is well, this is what produces these these extremely these atom thin sheets UM that that you then roll into a tiny tiny tube and by tiny tiny, I mean about a nanimeter or two in diameter UM and just you know, just to just to recover this nanimeter is one millionth of a millimeter, so it's one billionth of a meter, so it's small, right, And then you at least for the longest time, uh, these these carbon nanotubes could be

at most about a millimeter long. Now that's changed recently, right, right, But I mean even a millimeter long is pretty impressive because that's that's a million times as long as it is why that's I mean, that aspect ratio is incredible. I mean, it's one of the things that really made carbon nanotubes a fascinating thing to look at, because you're thinking, if you're looking at the dimensions, by one dimension, this is incredibly tiny, and by the other, in comparison, it

is ginormous. I mean, think about the technical term. Think if you saw a bus that was a million times longer than it was wide or or or long cat. If long CAT were so long that it were a million times longer. Thank you, Thank you Lauren for bringing it directly into analogy that is relatable to everybody. I was going with the bus, What was I thinking? I was mostly thinking I would not want to be behind that bus. I bet they would make really wide right

terms like we're on we're on the internet. Okay, we if we don't incorporate cats into the conversation, we're going to be fired, right, We're lost. But anyway, Yes, this is one of those amazing properties of of carbon nano tubes. The other thing that I find really interesting is that carbon ano tubes will have very different proper these depending upon how they are rolled, because it's mostly the direction

of the role. So it really is that how that those hexagons I was talking about in the graphing, how they are aligned in comparison to the actual role of this sheet. Uh. And depending on how you do it, it can behave like uh, like a metal, so a conductor, so it will conduct electricity. But if you roll it

a different way, like at a slightly different angle. And if you guys are having trouble visualizing this, just take a sheet of paper and roll it along the short side, or roll it along the long side, or roll it along the diagonal. These are all the different kinds of ways you can roll sheets of graphing, and you get different properties. So you roll it one way, it acts

metallic like a conductor, so it's conducting electricity. You roll it another way it acts like a semiconductor, which means that in some situations it does conduct electricity and in other situations it acts as an insulator. This gives it an incredible flexibility as far as applications are concerned. You can use it in all sorts of electronic applications, which we will get to in a little bit when Yeah, and it also depends on what kind of you can

roll them. Into all kinds of different interesting shapes using using an atomic force microscopes also called scanning force microscopes, which are which are things that have these these tiny bitty little nanimeter probes on the end of them, and you can use them to basically poke around a nanotube until it's the right shape, the right shape for your process. This is pretty amazing. I mean, we're talking about manipulating things that are just slightly larger than the atomic scale.

I mean, it's something that's really difficult to to visualize. Now, there there are some neat ways of kind of getting an idea of how precise we can be these days. My favorite we've talked about it on the Tech Stuff podcast in the past. My favorite illustration is that ibm UH several years ago used a similar type of microscope to manipulate individual atoms to all out I B M

on a silicon wafer. That is a delightful. Yeah, so you're talking about being able to when when we're able to manipulate individual atoms, then obviously this is we've got this level of precision that to me is mind boggling. I mean it's really exciting. But some of the other properties of carbon nanotubes is again depending upon the way you you you roll these tubes, it can be an incredibly strong material, stronger and lighter than say, steal, hundreds

of times stronger than steel. Yeah, according to to to some Well, you know, here's the thing. There's a theoretical limit to the tensile strength of carbon nanotubes, and then there's the limit that we've actually seen. Right, And as we get better about creating nanotubes than those two numbers get closer together. Right, But in general, in the experimental phase, you might not see as incredible a display of strength as you would expect when you start running the numbers

via you know math. But for an example, you could take a a cable that if you were to cut the cable and look at and measure the diameter you're talking about like a one millimeter diameter of this cable, like nanotube of that size could hold approximately six thousand, four or fourteen thousand pounds. And that's and and and a millimeter, I mean, that's that's what like like about the width of a human hair. Well, a millimeter would be one millionth of a nano million times the size

of a nanometer. That really brings it into perspective that I ruined my own joke. To be fair, I'm not working on very much sleep, right, I think I think a millimeter is about it's about the size of a head of a pin. Actually hair, human hair is like a few hundred thousand nanometers depending upon the person's hair, because human hair comes in a but but yes, I mean, the point being that you're talking about an incredibly thin cable that could hold an amazing amount of weight considering

the dimensions of the cable. Now granted again, this is theoretical, you know, when we talk about real carbon nanotubes and the real experiences we've had, it's a little bit different from that. But the potential there is to build certain types of materials, certain types of products using this stuff that can have fantastic properties. And uh that just to be clear, we're saying stronger than steel. That's really mostly tension strength when you're talking about um other types of impact.

Because carbon nanotubes are hollow, they can buckle. So let's say that you have just somehow you have managed to make one carbon nanotube that's you know, Lauren height, and then you have a force impacting that along the side of the carbon nanotube, so it's not pulling on the nanotube, it's pushing against the side, right into the chewy center.

Right that chewy center might just buckle and the carbon nanotube bends, and you think, well, that was But but it's the same sort of thing, like saying the strength of a rope. The strength of the rope is how much weight it can pull, not pushing against the rope, but the middle of the middle of the rope, it doesn't make any sense and it let's been pulled taut, And that's a whole different version of physics that we

would need to get into right, right exactly. But but that's one of the other things to keep in mind is that even though it is an incredibly strong material and theoretically one of the strongest materials we've encountered, uh,

that's only in specific use cases. It's not like you would build a carbon nanotube wall and it would be immune to everything else known to man, right, although I'm sure there are ways you could do that, like maybe with some sort of woven fabric made out of the carbon nanotubes, but an individual carbonanitude, it's not the case let's take a moment to thank our sponsor, and now

we'll return to our regular at least scheduled tech stuff podcasts. Alright, so, um, so there are there are many many applications that these nanotubes can be used for. Like, like we mentioned before, their engineers are looking at incorporating them into building materials, perhaps for vehicles. I mean, imagine if you had a vehicle that was six times lighter than than the cars

that are running around today, right that and that. If you're wondering why you would want a light car, one reason is that it means that you don't have to use as much fuel to push that car around. A lighter car means less work for the engine to do. If if the engine has to do less work, it theoretically needs less fuel. So we could end up with cars that are still gas powered but end up requiring far less fuel have greater efficiency. Or we could of course use it in other like hybrid cars and you

know you're again you're placing or even electric vehicles. Something like this airplane or yeah, yeah, there's some great airplanes would be fantastic because, as anyone has pointed out, if you're talking about someone who's who's green conscious and they're trying very hard to live a green friendly life. So they basically need to avoid airplanes entirely. One flight on a plane and you have just like you know, you're essentially erasing any good you're doing your entire you know,

green life at home. And that's that's just a hard reality of what it takes to move. Yeah, so that's a great example. You actually pointed out something else. A future use of this technology could be something that we did an episode of tech Stuff about a few years ago. Space elevators. Space elevators. Yeah, these are these are really nifty things. If you guys have not heard of this, um, you you should have by now, you're a bad tech stuff listener. But that's okay, because you can fix that.

I still love you, Yes, yes, no, No, I just I had to. I had to moderate a Facebook thread the other day. I am being the social media here. It has to work, So I'm if people are are being jerks on Facebook, they I'm the one who has to clean it up. So don't be jerks on Facebook, y'all. Um, it's a very special episode of tech Stuff. But no space elevator. No, well, I mean Okay, the point of my story here, I've started to stutter. Excellent. Um, the point of my of my story was that you shouldn't

be a jerk on Facebook. Now, No, I had a point. My point, Well, let me let me let me at least explain what space elevator is. How about that? Because I'm dying, you're here, I can, I can at least give it a shot. So let's say, let's let's say

you put an object into orbit, stationary orbit around the Earth. Okay, so it has to be uh, it's the object is sort of a counterweight, essentially, So you've got a counterweight orbiting the Earth, and the thing connecting the counterweight to Earth is a very strong cable, and you use this elevator which is essentially attached to the cable, to transport

in anything. Really, it could be people, although cargo would be a lot easier than people, because with people you gotta worry about, I don't know, keeping them alive and stuff moving them. Yeah, I guess if we're moving dead people, it's okay. So if we want to have a space cemetery out there, I wouldn't mind that, except that I actually plan on donating my body to science fiction. Uh so the uh, the yeah, you have an elevator that has this counterweight. Other, Okay, you're just that now I'm

with you. I'm with you, and keep going so the elevator can travel up the cable. The the nice thing about this is the based on this design, you might be using things like lasers to actually power this elevator. Uh. The elevator wouldn't have things on it like thrusters, like rocket thrusters, the way we would with a a traditional rocket ship to get stuff into space. It would mean that it would take uh less energy in theory to

deliver payloads to utter space. And you wouldn't have to worry about problems like uh, catastrophic failure when you're talking about propellants that can be incredibly dangerous under the wrong conditions. So and and also, I mean, just like we were saying, if you if you take one airline flight, you're basically erasing the entire good that you've done on your carbon foot print all year. You know, the cost of launch in terms of fuel and and just people and manpower

is is ten thousand dollars per pound. That's per kilogram. That's a bunch. So you've got you've got this need to find a cheaper way to get stuff into outer space if in fact we want to do that thing that which we do, I mean I do, yeah, because there's lots of fascinating stuff out there. So space elevators are a good way of doing that. But one of the problems is that how do you create a cable that's going to be strong enough and small enough to

make this a reality? And carbonana tubes might very well be the way that we solve that problem. Now, for a long time everyone said, okay, well here's the barrier, the barriers that we've got this on obtainium. We've got this. Yeah, yeah, we can make carbonano tubes, but there are a millimeter long at most, and so we don't have to make a whole bunch of them and tie the ends together teeny little bows in order to make a big, long

one for the cable, but relatively ineffective. Yea. So we'll get into some some new forms of manufacturer that have made that less of a problem. But even now we're still talking about this is science fiction as far as we're concerned. It's it's feasible, but not possible given our

technology right now, right now. But there are other applications that we could use carbonanotubes and including things like, uh like conductive plastics, So we can make electronics out of plastic materials and run carbon ano tubes through the plastic, creating them a conductive layer, so that you can actually make products even smaller than they are today. So instead of having a casing that is covering up the electronics, the case would be part of the electronics. You could

have you know, a credit card, thin smartphone. Yeah, yeah, that would that would turn More's law right on its point he had. Yep, yep, there's some pretty neat stuff that could potentially happen. We also could have things like smart fabrics, so clothing that could have carbon nanotubes in it that might do things like monitor conditions like it

could it could end up powering various sensors. This would obviously be very important in uniforms like space suits or first responders outfits for things like firefighters, things like that, you know, things that that could benefit from this. But even from a more consumer standpoint, we could even have I don't know, like clothing that tells you how active you are and whether or not you're getting enough exercise. Don't even have to put on a speedometer a little

Nike fit wristband, right you, you'd be fine. You just you know, you put on your clothing and that tells you or it may say things like, for Heaven's sake, wash me. You know that that goes out to everyone I went to college with. There other clothing applications. I mean, maybe not so much for daily use, but but carbonanotubes could be used to create some really terrific body armor.

Oh yeah, sure, yeah. Again, we're talking about the incredible strength, and if it's woven the right way, you're talking about something that could have a great applications for anyone who might be in military or law enforcement to provide a level of protection that is really, you know, unheard of at this point. I mean, we've got some great technology out there to keep people protected, but this would be a step of a huge step above that, assuming that we were able to, uh to find the right way

of weaving it. You know, part of the problem here is that we're talking about a material that's still a little challenging to manufacture, especially in mass quantities. But there have been improvements in carbon nano to manufacturing processes very recently. Yeah. Actually, um, we were, we were, and you know we're recording this

in early January, UM two thousand thirteen. And act really just today the Internet told me that, um that Rice University has announced a macroscopic hundreds of meters long mass producible carnin carbon nanotube thread. Yeah. This is this is incredible news because again, before we were talking about nanotubes that were a millimeter long, and that was considered huge. Now we're talking hundreds of meters. That is such an

enormous leap that it it boggles my mind. And it's all through this this wet method that they used to manufacture carbon nanotubes. Yeah, wet spinning method in which, um, and I'm sorry, I'm going to read this directly from my notes, which is probably a terrible thing to do, but in which clumps of nanotubes are dissolved in a bath of some acid stuff squirted through small holes to create long strands, and then the strands are wound into a big spool until they dry out. That's pretty incredible.

So really, the way I understand that is that we have dissolved the carbon nanotubes until they're essentially a liquid. You put them into what is essentially a nozzle, you squirted out in what is essentially like a giant icing thing where your favorite kind of cake, and you get this long string of carbon nanotube. That's exactly the way you want it to be until you get that you spoil it up and there you got you got a hundreds hundreds of meters long carbon nanotube. Yeah, it's it's

the thickness of a human hair. Um uh. And and not like I was saying earlier that you know, that's that's big. That's a bunch of a bunch of space things measurements of stuff. Yeah, it's much much larger than say, you know, on a single carbon nanotube would normally be you know, I get one billionth of a of a

meter in diameter. It's larger than that. Yes, And there there's a video and on the Internet of of an LED lamp being both suspended and powered by this thread, right, so so that it's this tiny like human hair with cord that's holding a a lightbulb, and the light bulb is lit because power is going through and and it's it's completely suspended that way. So you think about that, and you're like, all right, so we've got this very thin, very strong stuff that could provide power across it. This

could revolutionize electronics. Oh absolutely. And there's also there's also been a bunch of research into health applications for this. UM. It can be used as a delivery system for drugs and vitamins because carbon nanotubes are are so bitty that they can they can really get in there, you know, they you can you can attach you can attach stuff to them and send them in through things and and be really effective as an antioxidant. UM they naturally pick

up free radicals in UH in blood systems. Oh my, um, you can. One of one of the really cool bits of research that I saw had people UM sticking an antibody onto the end of a nanotube UM and then letting a blood sample pass through it, and different kinds of tumor cells or viruses will get trapped by that antibody and then UM, so you can you can test for all kinds of things without having to do any expensive lab work in the field in a couple hours. Interesting.

Of course, this also leads to a dark discussion and that carbon nanotubes may also be depending upon their their structure, may be extremely hazardous to our health. And uh, there are a couple of reasons for this. One is that when you're talking about things that are on the nano scale, their properties change fairly dramatically. You can have materials that act as conductors in the macro scale, but on the

nano scale they might be insulators. You also may have things that on the macro scale are perfectly safe, but on the nano scale are toxic. And one of the things that concerned people fairly early on in the research of carbon nanotubes, and has been studied extensively since then, is that carbon nanotubes, depending again on the specific structure that you've designed for them, bear a striking resemblance to

this substance called asbestos. And and for for for those young uns out there, this was an asbestos is a substance that used to be used in a lot of insulation. Um. Yes, it's fire retardant. Fire retardant, which which is great, I mean that's less fire good. Yes, yes, fire fire bad,

as Frankenstein's Monster taught us. However, um, you know, it was made up of these of these small pointy particles that people would aspirate and it would get stuck in the linings of your lungs and your other internal organs and cause cause lesions and metalalithiomia. No, that was not the word mesol. Yes, yes, the sea it's a form

of cancer. Cancer that the lining around your organs. That's specifically what what we're talking about here, but but more specifically the lungs, because you would breathe in these particles, and they're small enough so that they can, uh, they can infect a cell. Essentially, they can, uh, they can penetrate a cell. That's the best word for it, penetrate a cell. But they are large enough so that the body's immune system cannot easily get rid of them, which

is why it becomes a very dangerous substance. And the carbon anotubes bear some physical resemblance to those needle pointing fibers. Now, according to at least some research, I was reading one report that was kind of interesting, and I cannot pretend that I follow it completely because my my medical knowledge is uh, plucky and adventury. No wait, I'm sorry, that's my military knowledge. Um by the very model of a

modern tech stuff podcaster. They it was from an online library is actually from the Cancer and Aging Handbook, And the study suggested that carbon nanotubes could penetrate cells, but they did so in a different way than as best this particles did, Like they both could penetrate cells, and

they both could cause similar outcomes. So, in other words, there is some evidence that carbon nanotubes could in fact be carcinogenic, but they do it in a different mechanism, Like there's a different mechanism for how they are they get enveloped by other cells or by cells I should

say not other cells, but by cells. And so the research actually suggests that there might be ways of creating carbon nanotubes where they do not behave in this way where they are instead of causing cancer, they just kind of hang out, right, And that's one of the other problems about carbonano tubes is they have this bio persistence, meaning that if they are inside a biological entity, they do not tend to break down right there. They're so

strong and sturdy. Yeah, they don't react. They're nonreactive when it comes to that too, So you don't have it just you know, decomposed into some other material or get absorbed and then you know they're harmless, that's the problem. They don't do that. So, but there might be ways of of engineering carbon nanotubes so that they are not hazardous. And also all research I've read has suggested that it's

not that we shouldn't go into making carbon nanotubes. Yeah, yeah, yeah, it's it's most people are saying that, yes, it's a danger, but these things are so useful that we we almost can't afford to to not continue researching them. And that most most of the most of the danger comes to people who are going to be working in development development

labs creating them. Um And that there are definitely lots of different air filters and other precautions that could be used to to lessen the danger to these important workers. Um And And that ultimately we may find ways of creating these as you know, so safely that it becomes a non issue. Um. Not that you know, we can

ignore it. That's the important part is don't ignore the fact that there's a danger, but but understand that there may be ways of working around down that so that we minimize the danger to ourselves while maximizing the benefit that these things could provide us. So, yeah, I mean, it's it's you know, one of the things that definitely we have to keep in mind about technology. I mean, just like your computer at home, assuming you have one, has material in it that can be extremely toxic if

you are if you're exposed to it directly. But computers are incredible benefit too. It's just that it's under specific circumstances that you can become very dangerous. Like let's say you catch it, it catches on fire, that kind of thing, or you're taking it apart to try and harvest the various uh metals and minerals that are inside your computer. That would be a bad thing to do. Don't do that. So yeah, I mean it's just one of those things where you've got to keep in mind the various scenarios

and uh and and remember to to treat it carefully. So, um, guys, if you're out there playing with carbonanotubes, just you know, be careful. Yeah, do you know what you do in your spare time? Leave it to the professionals. Probably today, I think it's it's probably the important important thing there. But I find this this whole area of study very interesting. I mean, it does have the the potential to completely

revolutionize everything that has to do with electronics. I mean, you sit there and you think about how incredible things are right now, go and go to like ce Yes one year and take a look at a TV, and you see how thin they've become. Well, with this sort of technology, they could be even even, you know, so thin that when you mounted against the wall, you wouldn't be able to see the difference between the wall and the TV. I mean, that's that's how thin we're talking

basically a sticker. Just yeah, think. I mean, it's gonna take a while before we ever get there, but we can at least get to a point where it's gonna look like a piece of paper against the wall. I mean, so yeah, it's it's exciting stuff. I can't wait to see what happens. Me neither groovy. While we are of the same mind, excellent for once, never happen again. Guys,

write it down. So I suggest if any of you out there in our podcast listening world have suggestions for topics that Lauren and I should cover in future episode of tech Stuff and argue about. Yep, that'd be great. Send us a message. You can write us. Our email address is tech stuff at Discovery dot com or hey, our social media guru can pick it up if you happen to drop us a line on Facebook or Twitter.

Go to Facebook, go to Twitter, look for text stuff hs W. That's the handle we use at both those locations. Lauren and I will argue again really soon. For more on this and thousands of other topics, its works dot com