Happy Birthday, Buckyballs!
IRA FLATOW, host:
You're listening to SCIENCE FRIDAY, from NPR. I'm Ira Flatow.
Next up, a chemical anniversary. Twenty-five years ago this month, 1985, a series of experiments identified a new form of carbon, structured not like a flat sheet like your graphite in your pencil or a crystalline structure like a diamond on your ring, but pure carbon in a previously unidentified structure shaped like a soccer ball.
Joining me now is Sir Harry Kroto. He is founder of Global Educational Outreach for Science, Engineering and Technology, and the Vega Science Trust. He shared the 1996 Nobel Prize in Chemistry for the discovery of fullerenes, buckyballs as they're called. He's professor of chemistry at Florida State University in Tallahassee. Welcome back to SCIENCE FRIDAY, Dr. Kroto.
Dr. HARRY KROTO (Chemistry, University of Tallahassee; Recipient, 1996 Nobel Prize for Chemistry): It's a pleasure to be here, as usual.
FLATOW: Thank you. Twenty-five years. Have you had a party, a reunion, anything like that?
Dr. KROTO: We're going to have a party in Houston next month. The discovery was in September 1985 and the party will be in Houston. And so there's a big sort of celebration and conference, and meetings, and probably some good food, you never know.
(Soundbite of laughter)
Dr. KROTO: Maybe lucky.
(Soundbite of laughter)
FLATOW: I'm looking for my invitation.
Dr. KROTO: Well, I can make...
(Soundbite of laughter)
Dr. KROTO: I'm sure it can be arranged. Let me put that down on the list, okay?
(Soundbite of laughter)
FLATOW: Take us back those decades. What were you actually looking for that you came up with the buckyballs?
Dr. KROTO: Well, it's one of those wonderful serendipities. It's all blue-skies research, or, in the case of this - in this case, black skies research.
About the 1970s, we had detected some carbon chain molecules - very long carbon chain molecules - by radio astronomy. And then the development of infrared indicated there were some very interesting stars. And then a little bit later, these molecules were coming out. They're long carbon chains - just linear chains of carbon atoms.
And as luck would have it, I met Rick Smalley at Rice University, through my friend, Bob Curl. And as he - as Rick was jumping over the apparatus and excited about the breakthrough that he'd made, vaporizing metals and silica. And I thought, well, maybe you could vaporize graphite and simulate the conditions in a red giant star and see these carbon chains. It's a very simple idea.
And we did that a year later with students, Jim Heath and Sean O'Brien and Yuan Liu. And this crazy molecule just came out of the blue and said, you know, look, forget those linear stuff. I'm the biggest guy on the block.
A very strong signal, 60 carbon atoms hit us in the face and just - you couldn't miss it. It just was up there. Everything else paled into insignificance. And then, on the basis of ideas from Buckminster Fuller's geodesic domes and one, two other ideas, we concluded that maybe it was a geodesic dome, the shape of the soccer ball.
Dr. KROTO: And when we came to write the paper, I suggested we call it after Buckminster Fuller and call it Buckminster Fullerene. And then later, kids just love buckyballs and stuff like that, so it's been a great sort of serendipitous breakthrough.
FLATOW: And in the meantime, you've discovered you can engineer all kinds of things out of these buckyballs.
Dr. KROTO: Oh, there are something like 20,000 papers now on the chemistry of it. But also when it - the breakthrough in making it, which is about five years later - it's sort of 20th anniversary of that - by an American-German team, Kratschmer and Huffman, they found a very efficient way of making it.
It then became a big chemical sort of research program, for - everybody could work on it. But it also led to the discovery of the nanotubes or the buckytubes. And the - this has sprung off as a major area of nanotechnology research.
And very exciting because these nanotubes solve a lot of interesting problems and promise, I would say, the strongest material that could ever be made, but before we get there with all of these, some major technical issues to be solved in engineering, chemical engineering at the synthetic level to be solved.
FLATOW: Mm-hmm. I remember early on when we talked about this because the buckyballs were hollow.
Dr. KROTO: Yes.
FLATOW: We talked about filling it up with stuff and engineering it that way so you...
Dr. KROTO: Yeah, and that's an interesting point, because you can put an atom on the inside. In fact, the very first experiment after we concluded or conjectured that it was a cage was, well, how do you prove it? Well, if it's a cage, well, you know what you do with a cage, you put things inside.
Dr. KROTO: Well, it's too small to put a parrot in there...
(Soundbite of laughter)
Dr. KROTO: ...so the obvious thing is put an atom in the - inside. And I suggested iron. Let's put iron on the inside of it. But that didn't work. And -but Jim - he found that he could put lanthanum inside, and that was the second paper, that we could put an atom on the inside. And that was very important circumstantial evidence that our idea that it was a cage was actually correct.
FLATOW: Mm-hmm. We've heard of all kinds of new things and - made out of carbon, different kinds of a carbon. What is this thing called graphene?
Dr. KROTO: Well, graphene is very interesting. It's a single sheet of graphite. Graphite is actually a sandwich structure. So when you have a pencil - if you actually - what you're doing is you'd write - you're shaving graphite onto the paper. Now, these sheets are, sort of flow off the pencil - imagine you've got a - well, what - a huge number of little rafts.
But these are multiple sheets. We have something called Licorice Allsorts in the UK, which are little toffees which are made of little sandwiches of, you know, 10 layers of these things. But if you take a single layer off the top, you have a very interesting material which is now the subject of a lot of study, has some very interesting electrical and electronic properties. And it's opened up a new field of carbon chemistry.
So it's not that the graphene wasn't known before. It's just that nobody had thought of trying to take a single sheet of these. And the single sheet has interesting properties that differ considerably from a bulk system in which you've got hundreds of sheets stuck together.
FLATOW: Mm-hmm. And now I've heard it said, probably by you, that buckyballs that - are the most pure form of carbon. Even though we've heard of other carbons like, you know, that's in a diamond ring and stuff like that.
Dr. KROTO: Well, yes. You see, the problem with diamond is that, on the surface, there are carbon atoms. And if - the surface carbon atoms are what we called dangling bonds, and they're very reactive. So the surface of diamond is not carbon, in general. It's hydrogen and oxygen, and whatever comes out of the atmosphere, water vapor. But if you put the diamond in a very high vacuum and clean the surface, then you've got a very unusual sort of surface which you don't always have. So diamond is never - can never be actually pure, because there must be something - a very thin layer of just single atoms on the surface. So you don't notice it, because they're pretty small.
And the same is true of graphite. On the edges of graphite, you have what are called dangling bonds. So, in graphite, you have hydrogen or hydroxyl groups. So that's not pure as well. Now, in the case of C-60, however, the beautiful guy, it's curved into a ball. And so it gets rid of its edges by curving into a round structure.
And it's a little bit - there's a little bit of a comparison with water. When you have a large of amount of water, it's flat, pulled down by gravity. But if you have a small droplet, it curves into a ball by surface tension, right? You know, if you - a droplet on the leaf.
Dr. KROTO: You've seen those photographs. And everybody's seen those beautiful photographs of insects on leaves and water droplets. At a very small scale, the structure is controlled by surface tension. And that's the case in nanotechnology, that in the case of very small numbers of atoms, they're controlled often by different forces than is the case when you have a large number of - millions and millions of atoms.
FLATOW: Mm-hmm. What is there about the shape of buckyballs, the C60, that makes them so un- amenable to use them in chemical engineering ways in shaping...
Dr. KROTO: Well, there are interesting aspects. I mean, the first one that I -most interests me, and I think is probably the one that will, in the future, be important is that, because it's a round object, it can trap electrons on the surface. And so it can store electrons better than almost any other molecule. And that's very useful in things like solar energy production and in organic solar cells, I think Alan Heeger at Santa Barbara - also a Nobel Prize-winner for his work on organic solar conduction - has been developing materials which could be printed onto, say, plastic, as a solar cell by printing press technology. This is very exciting. And what you need are the molecules with - which are very -have some very important characteristics. One is to capture electrons and not let them go. And that's what C60 can do.
The other interesting thing, of course, is you can put something on the inside of it, and it's physically trapped rather than chemically trapped. Now, this is really interesting, because let's say you're thinking about chemotherapy. And very many of the radiating - radioactive elements that are used in chemotherapy and radiation therapy are actually toxic, right? So if you put it inside C60, it should be possible to tag the outside of the C60, trap the radioactive, toxic atom on the inside and use it, put it close to, say, the cancer tissue, but it won't have its toxic problems that one has in chemotherapy.
The big problem in chemotherapy - as those who had it will realize - it's not the radiation, but that - but often, it's the toxicity of the agent that's being used. Now that's because...
FLATOW: So that won't...
Dr. KROTO: ...it's chemically bonded.
FLATOW: Yeah. It won't leak out of a buckyball.
Dr. KROTO: No, it can't get out of the buckyball, and that's - it's physically caged in a different way from standard chemical problems. And that's an interesting aspect that people are trying to look at. And also, with, say, agents in MRI, what are called a relaxing agent that relax the spins in an MRI. It should be possible to make them nontoxic by putting them inside the buckyball.
Dr. KROTO: Theoretically, anyway.
Dr. KROTO: But it's tricky stuff.
FLATOW: Yeah. But I - you're the man to do it, I think.
Dr. KROTO: Well, not really, because I'm - my - you know, I - we discovered it because we were working in a particular area. I'm not really working on that. I work on things that interest me. And now what interests me is the fantastic results from about six weeks ago from NASA - the detection of C60 in space. Because when we discovered it, we found it in - under conditions produced in carbon stars. We reproduced the conditions in the carbon star in the laboratory.
And at that point, it was telling us that maybe this stuff was coming out of the stars as well. And in 1995, with Mike Jura at UCLA, we published a paper suggesting that if it was in space, it should be responsible for some very puzzling features that have been known for 90 years called the diffuse interstellar bands. And I think now that it's been detecting in space, that particular paper looks really rather interesting.
It now looks - I mean, I've just been talking to Mike in California by email, and the estimates are that 1 percent of the carbon in the interstellar medium may be in the form of C60. And that's fantastic because it's the third of carbon, and it reminds me of the "The Third Man" - you know, Orson Welles and "The Third Man"?
FLATOW: Yeah. I remember that theme, "The Third Man" theme. Yeah, I remember it. Yeah.
Dr. KROTO: Yeah, absolutely. And so here's this guy, lurking in the shadows of Vienna, and here's this molecule lurking in the dark recesses of the galaxy. And it's been there all the time. And, Ira, you have made it, believe it or not.
FLATOW: I have made it.
Dr. KROTO: Yes, you have. Because every time you turn a Bunsen burner to yellow, you make C60.
FLATOW: There you go. There's the project for the weekend.
Dr. KROTO: Yup. But you have to suck it out of the center of the flame, because as it goes through the flame barrier, it's lost again.
FLATOW: Don't try this at home.
Dr. KROTO: No.
(Soundbite of laughter)
FLATOW: All right, Harry. Thanks for - stay off those Ferris wheels.
Dr. KROTO: Yup. See you soon. Bye.
FLATOW: Bye-bye. Sir Harry Kroto, who is - who won the Nobel Prize, the 1996 Nobel Prize for the discovery of buckyballs. And he's a professor of chemistry at Florida State University.
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