Fullerenes are a remarkable class of molecules in which large numbers of carbon molecules are locked together into a roughly spherical shape. Their construction roughly resembles the interlocked trusses of Buckminster Fuller's famous geodesic domes, which is why these molecules are called fullerenes or buckyballs. Although they are fascinating from a purely scientific point of view, their utilitarian value is not so clear.
John H. Weaver is the head of the Electronic Materials Group in the department of chemical engineering and materials science at the University of Minnesota; he was recently named 1997 Scientist of the Year by R&D Magazine. Weaver describes the current thinking on this topic:
"There has been considerable interest in practical applications for fullerenes (buckyballs) since Wolfgang Kratschmer and Donald R. Huffman first demonstrated a way to produce these molecules in quantity (see their article in Nature, Vol. 347, pages 354-358; September 27, 1990). Questions like the one posed here challenge the materials researcher and the R&D community to take advantage of a new opportunity. At the same time, one should not be too disappointed if the answer is 'not yet.'
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"In the early days (1990 and 1991), there was much speculation about the potential uses of fullerenes. After all, they represented an unexpected new form of crystalline carbon (joining graphite and diamond, both of which have many commercial uses); they have elegant forms (C60, composed of 60 carbon atoms, has a soccer-ball shape); and they are hollow (suggesting that they might be filled). These all-carbon molecules captured the attention of scientists and laymen alike and generated considerable coverage by the popular press. At scientific meetings, someone was bound to ask about applications for these exotic molecules. Researchers generally tried to be optimistic while remaining circumspect and cautious--who, after all, can see the future clearly? Nevertheless, there was much hype, and some rather extravagant stretches of the imagination surfaced as the media tried to find catchy phrases to describe the nature and potential of fullerenes.
"To date, no products based on fullerenes have had a significant financial impact. That is not to say that such products will not ever exist. It is only to say that the fullerene-based field of materials research is young, that opportunities remain to be explored and exploited, and that the jump from discovery to widespread application takes time. It took years, for example, to move from the first demonstration of semiconductor-based electronic devices to transistors and integrated circuits in commercial products.
"For fullerenes, the transition from discovery to application is different from that for other materials-related breakthroughs. For example, looking back a decade on the discovery of superconductivity in the cuprates (copper-containing materials that transport electricity without resistance at relatively high temperatures), it was clear from the beginning that these materials would find markets in current-carrying applications, once costs and technical problems were overcome. With the fullerenes, there is still a fundamental uncertainty as to what the applications will be. They show some promise as electrical conductors and lubricants, for example, but it is not yet clear how effectively those properties can be exploited.
"There are two ways in which fullerenes could form the basis of a competitive product. First, they might exhibit a property so remarkable that they could be used to create products unlike any now on the market. Once this revolutionary product were demonstrated, the costs associated with manufacturing fullerenes would be reduced by ramping up to large-scale production. The hard part has been thinking up such a unique application for fullerenes.
"The second path to commercialization lies through competition with existing products. In this case, the new product would have to be better, cheaper, less harmful to the environment or in some other way superior to what is now available. Although researchers have had no shortage of ideas for uses of fullerenes, none of these have yet been shown to be commercially competitive. After all, we already have effective lubricants, steadily improving superconductors and so on.
"Many very clever people are currently working on possible commercial uses for fullerenes. There may be a breakthrough just around the corner, but the applications sector is likely to establish property rights before disclosing the breakthrough. A quick search of the Internet using the keywords 'fullerene patents' returns many hits, and going to the Fullerene Patent Database leads to a list of 149 related patents awarded through 1996.
"When considering the ultimate real-world impact of fullerenes, it is important that we not keep our horizon too narrowly focused. For example, one direct outcome of fullerene research has been the discovery of carbon-based nanotubes. [Editors' note: These are structures in which crystalline arrays of carbon atoms form tiny, hollow cylinders.] These structures are yet another example of a new molecular structure that, with a fertile imagination, might lead to a commercial product--perhaps by aiding in the study and manipulation of materials at the atomic scale. A technology based on nanotubes might never have come had it not been for the discovery of fullerenes. Such is the connectedness of science.
"Are there recognized applications of fullerenes today that are guaranteed to have an effect on the lives of our children in, say, 2050? Not to my knowledge. But will such applications eventually arise? I feel comfortable that they will. Incidentally, there was a scene in Star Trek: The Next Generation in which Worf's son Alexander produced fullerenes in chemistry class and filled them with water. This 24th-century science experiment may not constitute an application, but another Star Trek episode mentioned the use of C70 (a 70-atom fullerene) in a communicator."