На главную
Вы находитесь в Хранилище файлов Белорусской цифровой библиотеки

Bruce Sterling. Buckymania


bruces@well.sf.ca.us
Literary Freeware: Not For Commercial Use From THE MAGAZINE OF FANTASY AND SCIENCE FICTION, July 1992 F&SF Box 56 Cornwall CT 06753 $26/yr; outside USA $31/yr F&SF Column #2 BUCKYMANIA Carbon, like every other element on this planet, came to us from outer space. Carbon and its compounds are well-known in galactic gas-clouds, and in the atmosphere and core of stars, which burn helium to produce carbon. Carbon is the sixth element in the periodic table, and forms about two-tenths of one percent of Earth's crust. Earth's biosphere (most everything that grows, moves, breathes, photosynthesizes, or reads F&SF) is constructed mostly of waterlogged carbon, with a little nitrogen, phosphorus and such for leavening. There are over a million known and catalogued compounds of carbon: the study of these compounds, and their profuse and intricate behavior, forms the major field of science known as organic chemistry. Since prehistory, "pure" carbon has been known to humankind in three basic flavors. First, there's smut (lampblack or "amorphous carbon"). Then there's graphite: soft, grayish-black, shiny stuff -- (pencil "lead" and lubricant). And third is that surpassing anomaly, "diamond," which comes in extremely hard translucent crystals. Smut is carbon atoms that are poorly linked. Graphite is carbon atoms neatly linked in flat sheets. Diamond is carbon linked in strong, regular, three-dimensional lattices: tetrahedra, that form ultrasolid little carbon pyramids. Today, however, humanity rejoices in possession of a fourth and historically unprecedented form of carbon. Researchers have created an entire class of these simon-pure carbon molecules, now collectively known as the "fullerenes." They were named in August 1985, in Houston, Texas, in honor of the American engineer, inventor, and delphically visionary philosopher, R. Buckminster Fuller. "Buckminsterfullerene," or C60, is the best-known fullerene. It's very round, the roundest molecule known to science. Sporting what is technically known as "truncated icosahedral structure," C60 is the most symmetric molecule possible in three-dimensional Euclidean space. Each and every molecule of "Buckminsterfullerene" is a hollow, geodesic sphere of sixty carbon atoms, all identically linked in a spherical framework of twelve pentagons and twenty hexagons. This molecule looks exactly like a common soccerball, and was therefore nicknamed a "buckyball" by delighted chemists. A free buckyball rotates merrily through space at one hundred million revolutions per second. It's just over one nanometer across. Buckminsterfullerene by the gross forms a solid crystal, is stable at room temperature, and is an attractive mustard-yellow color. A heap of crystallized buckyballs stack very much like pool balls, and are as soft as graphite. It's thought that buckyballs will make good lubricants -- something like molecular ball bearings. When compressed, crystallized buckyballs squash and flatten readily, down to about seventy percent of their volume. They then refused to move any further and become extremely hard. Just *how* hard is not yet established, but according to chemical theory, compressed buckyballs may be considerably harder than diamond. They may make good shock absorbers, or good armor. But this is only the beginning of carbon's multifarious oddities in the playful buckyball field. Because buckyballs are hollow, their carbon framework can be wrapped around other, entirely different atoms, forming neat molecular cages. This has already been successfully done with certain metals, creating the intriguing new class of "metallofullerites." Then there are buckyballs with a carbon or two knocked out of the framework, and replaced with metal atoms. This "doping" process yields a galaxy of so-called "dopeyballs." Some of these dopeyballs show great promise as superconductors. Other altered buckyballs seem to be organic ferromagnets. A thin film of buckyballs can double the frequency of laser light passing through it. Twisted or deformed buckyballs might act as optical switches for future fiber-optic networks. Buckyballs with dangling branches of nickel, palladium, or platinum may serve as new industrial catalysts. The electrical properties of buckyballs and their associated compounds are very unusual, and therefore very promising. Pure C60 is an insulator. Add three potassium atoms, and it becomes a low- temperature superconductor. Add three more potassium atoms, and it becomes an insulator again! There's already excited talk in industry of making electrical batteries out of buckyballs. Then there are the "buckybabies:" C28, C32, C44, and C52. The lumpy, angular buckybabies have received very little study to date, and heaven only knows what they're capable of, especially when doped, bleached, twisted, frozen or magnetized. And then there are the *big* buckyballs: C240, C540, C960. Molecular models of these monster buckyballs look like giant chickenwire beachballs. There doesn't seem to be any limit to the upper size of a buckyball. If wrapped around one another for internal support, buckyballs can (at least theoretically) accrete like pearls. A truly titanic buckyball might be big enough to see with the naked eye. Conceivably, it might even be big enough to kick around on a playing field, if you didn't mind kicking an anomalous entity with unknown physical properties. Carbon-fiber is a high-tech construction material which has been seeing a lot of use lately in tennis rackets, bicycles, and high- performance aircraft. It's already the strongest fiber known. This makes the discovery of "buckytubes" even more striking. A buckytube is carbon-fiber with a difference: it's a buckyball extruded into a long continuous cylinder comprised of one single superstrong molecule. C70, a buckyball cousin shaped like a rugby ball, seems to be useful in producing high-tech films of artificial diamond. Then there are "fuzzyballs" with sixty strands of hydrogen hair, "bunnyballs" with twin ears of butylpyridine, flourinated "teflonballs" that may be the slipperiest molecules ever produced. This sudden wealth of new high-tech slang indicates the potential riches of this new and multidisciplinary field of study, where physics, electronics, chemistry and materials-science are all overlapping, right now, in an exhilirating microsoccerball scrimmage. Today there are more than fifty different teams of scientists investigating buckyballs and their relations, including industrial heavy-hitters from AT&T, IBM and Exxon. SCIENCE magazine voted buckminsterfullerene "Molecule of the Year" in 1991. Buckyball papers have also appeared in NATURE, NEW SCIENTIST, SCIENTIFIC AMERICAN, even FORTUNE and BUSINESS WEEK. Buckyball breakthroughs are coming well-nigh every week, while the fax machines sizzle in labs around the world. Buckyballs are strange, elegant, beautiful, very intellectually sexy, and will soon be commercially hot. In chemical terms, the discovery of buckminsterfullerene -- a carbon sphere -- may well rank with the discovery of the benzene ring -- a carbon ring -- in the 19th century. The benzene ring (C6H6) brought the huge field of aromatic chemistry into being, and with it a enormous number of industrial applications. But what was this "discovery," and how did it come about? In a sense, like carbon itself, buckyballs also came to us from outer space. Donald Huffman and Wolfgang Kratschmer were astrophysicists studying interstellar soot. Huffman worked for the University of Arizona in Tucson, Kratschmer for the Max Planck Institute in Heidelberg. In 1982, these two gentlemen were superheating graphite rods in a low-pressure helium atmosphere, trying to replicate possible soot-making conditions in the atmosphere of red-giant stars. Their experiment was run in a modest bell-jar zapping apparatus about the size and shape of a washing-machine. Among a great deal of black gunk, they actually manufactured miniscule traces of buckminsterfullerene, which behaved oddly in their spectrometer. At the time, however, they didn't realize what they had. In 1985, buckministerfullerene surfaced again, this time in a high-tech laser-vaporization cluster-beam apparatus. Robert Curl and Richard Smalley, two professors of chemistry at Rice University in Houston, knew that a round carbon molecule was theoretically possible. They even knew that it was likely to be yellow in color. And in August 1985, they made a few nanograms of it, detected it with mass spectrometers, and had the honor of naming it, along with their colleagues Harry Kroto, Jim Heath and Sean O'Brien. In 1985, however, there wasn't enough buckminsterfullerene around to do much more than theorize about. It was "discovered," and named, and argued about in scientific journals, and was an intriguing intellectual curiosity. But this exotic substance remained little more than a lab freak. And there the situation languished. But in 1988, Huffman and Kratschmer, the astrophysicists, suddenly caught on: this "C60" from the chemists in Houston, was probably the very same stuff they'd made by a different process, back in 1982. Harry Kroto, who had moved to the University of Sussex in the meantime, replicated their results in his own machine in England, and was soon producing enough buckminsterfullerene to actually weigh on a scale, and measure, and purify! The Huffman/Kratschmer process made buckminsterfullerene by whole milligrams. Wow! Now the entire arsenal of modern chemistry could be brought to bear: X-ray diffraction, crystallography, nuclear magnetic resonance, chromatography. And results came swiftly, and were published. Not only were buckyballs real, they were weird and wonderful. In 1990, the Rice team discovered a yet simpler method to make buckyballs, the so-called "fullerene factory." In a thin helium atmosphere inside a metal tank, a graphite rod is placed near a graphite disk. Enough simple, brute electrical power is blasted through the graphite to generate an electrical arc between the disk and the tip of the rod. When the end of the rod boils off, you just crank the stub a little closer and turn up the juice. The resultant exotic soot, which collects on the metal walls of the chamber, is up to 45 percent buckyballs. In 1990, the buckyball field flung open its stadium doors for anybody with a few gas-valves and enough credit for a big electric bill. These buckyball "factories" sprang up all over the world in 1990 and '91. The "discovery" of buckminsterfullerene was not the big kick- off in this particular endeavour. What really counted was the budget, the simplicity of manufacturing. It wasn't the intellectual breakthrough that made buckyballs a sport -- it was the cheap ticket in through the gates. With cheap and easy buckyballs available, the research scene exploded. Sometimes Science, like other overglamorized forms of human endeavor, marches on its stomach. As I write this, pure buckyballs are sold commercially for about $2000 a gram, but the market price is in free-fall. Chemists suggest that buckmisterfullerene will be as cheap as aluminum some day soon -- a few bucks a pound. Buckyballs will be a bulk commodity, like oatmeal. You may even *eat* them some day -- they're not poisonous, and they seem to offer a handy way to package certain drugs. Buckminsterfullerene may have been "born" in an interstellar star-lab, but it'll become a part of everyday life, your life and my life, like nylon, or latex, or polyester. It may become more famous, and will almost certainly have far more social impact, than Buckminster Fuller's own geodesic domes, those glamorously high-tech structures of the 60s that were the prophetic vision for their molecule-size counterparts. This whole exciting buckyball scrimmage will almost certainly bring us amazing products yet undreamt-of, everything from grease to superhard steels. And, inevitably, it will bring a concomitant set of new problems -- buckyball junk, perhaps, or bizarre new forms of pollution, or sinister military applications. This is the way of the world. But maybe the most remarkable thing about this peculiar and elaborate process of scientific development is that buckyballs never were really "exotic" in the first place. Now that sustained attention has been brought to bear on the phenomenon, it appears that buckyballs are naturally present -- in tiny amounts, that is -- in almost any sooty, smoky flame. Buckyballs fly when you light a candle, they flew when Bogie lit a cigarette in "Casablanca," they flew when Neanderthals roasted mammoth fat over the cave fire. Soot we knew about, diamonds we prized -- but all this time, carbon, good ol' Element Six, has had a shocking clandestine existence. The "secret" was always there, right in the air, all around all of us. But when you come right down to it, it doesn't really matter how we found out about buckyballs. Accidents are not only fun, but crucial to the so-called march of science, a march that often moves fastest when it's stumbling down some strange gully that no one knew existed. Scientists are human beings, and human beings are flexible: not a hard, rigidly locked crystal like diamond, but a resilient network. It's a legitimate and vital part of science to recognize the truth -- not merely when looking for it with brows furrowed and teeth clenched, but when tripping over it headlong. Thanks to science, we did find out the truth. And now it's all different. Because now we know!

Last-modified: Sat, 23 May 1998 08:27:13 GMT
World LibraryРеклама в библиотекеПроект для детей старше 12 лет!
Проект Либмонстра, партнеры БЦБ - Украинская цифровая библиотека и Либмонстр Россия
https://database.library.by