Now I’m not a chemist, and there may be other elements in
the periodic table that are cooler than carbon, but I can’t think of one. First off, it’s the 4th most
prevalent element in the universe, after hydrogen, helium, and oxygen, and the
15th most abundant element in the earth’s crust. It makes up all living things on earth,
not to mention other important stuff like oil, natural gas, and carbon dioxide.
And most scientists believe that
if life is found outside earth, it will be based on carbon.
Carbon is very interesting at the molecular level, that is,
in the varied shapes that molecules made of pure carbon atoms can assume and
the surprisingly different properties that a simple shape change can provide. For example, a diamond and a lump of
coal are identical at the atomic level—they are made solely of carbon
atoms. But they differ widely at
the molecular level. The carbon
atoms in a diamond are arranged in a lattice design while those in a coal
molecule have no structure—they are amorphous. And of course, the lattice design of a diamond makes it
transparent, while the amorphous structure of coal makes it just the opposite.
But coal and diamonds are not the forms of carbon I’m going
to talk about today. I’m more
interested in the “chicken wire” forms.
That’s right, chicken wire. Think of all the different shapes you can make with chicken wire—and carbon can probably manage
every single one of them.
I’d really like to focus on just three shapes: sheets of chicken wire, spheres of
chicken wire, and tubes of chicken wire. To see examples of these and other forms of carbon, take a
look at the diagram below: diamond (a), graphene (b), ionsdaleite
(c), buckyballs (d, e, f), amorphous carbon (g), and a nanotube (h).
Let’s start with buckyballs. Now stay with me here. Buckyballs (as well as nanotubes) are classed as
“fullerenes,” a word that comes from the last name of the very famous inventor
and futurist Buckminster Fuller, whose first name also gave us the “bucky” in
buckyballs. Fuller
popularized dome homes, which he patented as a “Geodesic Dome” as U.S. Patent
No. 2,682,235 in 1954 (the first geodesic dome was actually developed and built
in 1923 by Walther Bauersfeld, a German engineer, which makes me wonder if
Fuller’s patent was valid). Certainly
the spheroid dome shape has in some ways come to symbolize science, technology,
and the future. Think of the dome
at Epcot, for example. And so in
this way Buckminster Fuller has become associated with really cool space-age
technology.
Now, spherical shapes can be constructed out of a number of
geometric forms. Fuller’s dome
homes had triangular faces, but a soccer ball made by Adidas in 1970 was
constructed of 12 black pentagons and 20 white hexagons; it was called the
Telstar soccer ball. (Does this
give you a strong urge to run out and grab up a soccer ball to see if you have
a Telstar or not? I wish I had
known this when my kids were younger—there was a teaching moment there!)
The word Telstar comes from the Telstar 1 and 2 satellites
launched back in 1962 and 1963, and you’d like to think that as the progenitor
of the soccer ball, they were also made of pentagons and hexagons—but no such
luck. The satellites were made up
of rectangles and squares in a roughly spheroid shape.
Okay, back to buckyballs. The theoretical existence of buckyballs was first discussed
in the 1960’s and 1970’s, and in 1980 it was predicted that spherical particles
of carbon could be created in the laboratory. However, it was not until 1985 that researchers published a paper
reporting that spherical molecules consisting of 60 carbon atoms, labeled C60,
had been produced at Rice University.
Although the scientists who conducted this experiment couldn’t actually
“see” the structure formed by this carbon molecule, it was eventually found to
be a sphere composed of 12 pentagons and 20 hexagons. And their groundbreaking article actually included a photo
of an Adidas soccer ball to illustrate the point!
The original paper was authored by five chemists (three of
whom were awarded the Nobel Prize in 1996—R. Curl, H. Kroto, and R. Smalley), and
they came up with the name “buckminsterfullerene” for the spherical carbon
molecule they had created. With a touch
of humor seldom found in scientific journals, they also suggested that perhaps
it should have been named “soccerene” or “carbosoccer.” Personally I think these molecules should
have been called “Telstar balls” or even “Adidas balls”, but I suspect that
kind of industrial affiliation would have been anathema to these academic
researchers.
Soon afterwards, thousands of papers were published
examining buckyball chemistry and production. Their spherical shape, plus the possibility of trapping metals
and other elements inside, caused a veritable land rush of scientists who immediately
embarked on new research programs to investigate potential ramifications and
applications. Many possible uses
of buckyballs have been identified, including superconductors, lubricants,
catalysts, drug delivery systems, hydrogen storage, optics, chemical sensors,
and even cosmetics.
So here we are, 28 years after this momentous discovery, and
it is reasonable to ask whether the early commercial promise of buckyballs has
been realized. (I don’t consider buckyballs
produced for research purposes to be commercial products. You can, however, purchase them by the
gram from SES Research in Houston, Texas, for $45. At 454 grams per pound, that’s $20,430, so it will be a long
time before you see buckyballs in your oil change. )
It seems that a medical buckyball product may be the one
that is closest to market. It is a
C80 spheroid that can be manufactured in such a way as to trap
several different types of metals, including scandium, yttrium, erbium,
lutetium, and gadolinium. These strange-sounding
metals (which are “related” to aluminum) have many very specialized uses. For example, gadolinium is used as a
contrast agent for magnetic resonance imaging (MRI) because it helps improve
the visibility of internal organs and other structures. Virginia Tech University discovered and
patented the method of making these metal-trapping buckyballs and licensed its rights
to a Virginia company called Luna Nanoworks. The company has developed one C80 spheroid called
Trimetasphere that contains three metals, and they are investigating its use as
a new MRI contrast agent. Oh, and
H. Kroto, one of the Nobel Prize winners, is an advisor to the company.
So how well is Luna Nanoworks doing financially? It is a publically-traded company with
a market capitalization of $17 million.
Its stock has been selling at around $1.25 since 2011 (down from about $5
a share in 2009), so I presume it hasn’t had much in the way of commercial
sales.
Unfortunately I think we can put buckyballs in the category
of really really cool science that has an equally cool name but that doesn’t
have a commercial application—yet. It’s hard making money on science, even really really cool
science. Think about that.
Next up is the other fullerene that you’ve probably heard
about: nanotubes (see “f” in the
diagram at the beginning of this blog).
Now, when it comes to the question of who discovered what and
when in the nanotube world, the story can get pretty contentions. Some give the award to Sumio Lijima, a
Japanese physicist with the NEC company who reportedly succeeded in producing
nanotubes in the lab in 1991. He
also examined these new structures under an electron microscope and correctly speculated
on their structure (Lijima’s diagram looks like rolled-up chicken wire). But others believe that carbon
nanotubes were actually produced and photographed decades earlier. They point to two Russians who published
an article in 1951 along with pictures of what some people claim to be
nanotubes—but the paper was written in Russian and, due in part to the Cold
War, wasn’t available to Western scientists for a long time. Since I myself don’t read Russian, I
can’t tell you how these scientists came up with their nanotubes (if nanotubes
they were), but they definitely didn’t clearly lay out the molecular structure the
way Lijima did in 1991.
One of the coolest things about a carbon nanotube is its
long length compared to its width, with a ratio of 132,000,000:1, which is
greater than that of any other molecule found so far. So if you had a nanotube that was an
inch wide, it would be 2,000 miles long!
Nanotubes are also the strongest and stiffest materials known—with
tensile strength equivalent to that of a 1 mm2 cable capable of supporting
14,158 pounds. In addition,
nanotubes can conduct electricity 1,000 times better than copper, and some
scientists claim that they are capable of behaving like a superconductor
(although this is somewhat controversial).
On the negative side, nanotubes have been shown to induce an
inflammatory response, and because their structure is somewhat similar to that of
asbestos fibers, concerns have been raised about possible carcinogenicity.
Although the nanotube’s interesting properties have caused
speculation about many different types of applications, the actual products
sold so far are designed to capitalize primarily on the molecule’s strength. Consequently nanotubes have been
used in such things as bicycle components, skis, hockey sticks, hunting arrows,
clothing, and resins and paints for wind turbines and boats.
But I would have to give the award for the “Most Bizarre Use
of Nanotubes” (I hesitate to use the word “cool” yet again, but that is what I
am thinking) to an application that would take advantage of the nanotube’s high
length-to-width ratio: a space
elevator with one end tethered to the ground and the other end, well, out in
space. For transporting stuff back
and forth between the earth and the International Space Station maybe.
Certainly one of the coolest (neatest?!) near-term applications
of nanotubes has got to be the paper battery. Originally reported in the scientific literature by
scientists at Rensselaer Polytechnic Institute in 2007, these batteries are
composed of cellulose (paper), an ionic liquid (1-ethyl-3-methylimidazolium
chloride), and nanotubes. They
produce between 2 and 8 volts of electricity, and since they are paper thin,
they appear to be ideally suited for electronic devices such as cell phones and
medical devices. A new venture
founded in 2008 (with the unsurprising name of Paper Battery Co.) plans to have
a commercial product on the market by 2014.
And finally, the most recent carbon cousin—graphene. Think of a single sheet of chicken
wire. The world got its first real
glimpse of this molecular structure in 2004, when Andre Geim and Konstantin
Novoselov at the University of Manchester, England, isolated graphene using
Scotch tape. Yes, indeed—they took
some commercially available graphite, and stuck it to some Scotch tape. Then they peeled the Scotch Tape off
and, voila, they found that they had single layers of graphene. Kind of like lifting pancakes off your
plate with duct tape wrapped around your hand. You get the idea.
This little experiment started another virtual gold rush of entrepreneurs
hunting for commercial applications. Like its buckyball and nanotube cousins, graphene has many
unique properties—like being very strong and a great conductor of electricity,
as well as having the ability to absorb and re-emit light over a greater range
of wavelengths than any other known material. And being only one atom thick, it is also the thinnest
material known. So graphene is currently
being investigated for a wide variety of not-yet-commercial products, including
electronic newspapers (e-paper), batteries, flexible electric circuits, and touch
screens, not to mention desalinating water, sequencing DNA, and strengthening a
wide array of other products.
For example, researchers at Michigan Technological
University have shown that platinum (a very expensive metal) can be replaced with
graphene in solar cell electrodes.
And scientists at Monash University in Australia have made graphene
“supercapacitors” (batteries that can charge and recharge instantly) with as
much energy density as a car battery.
And as an example of how one discovery can lead to another,
scientists in 2012 reported that they have been able to grow glass on graphene. That’s right, for the first time ever, researchers
have produced a layer of glass only two atoms thick—on top of a layer of
graphene. And just like graphene,
the glass looks like chicken wire , but since it is glass, it is composed of
silicon and oxygen rather than carbon (glass is SiO2). And who knows what its possible uses
are—the authors speculate that it might be used in semiconductors or in “layered
graphene electronics as a passivated starting layer for gate insulators.” Whatever that is.
The problem is that, like nanotubes, graphene is expensive
to produce. As a result,
Graphenea, a Spanish company founded in 2010, will sell you a mere ½-inch
square of single-layer graphene mounted on silicon dioxide for the whopping
price of $330. Or you can
buy 250 ml of graphene oxide (advertised for use in batteries, solar cells,
supercapacitors, and graphene research) for the slightly-less-shocking sum of $131.
So graphene won’t be widely used in commercial products
until the cost comes down. Unless,
of course, you are selling small and very expensive products—like high-end graphene
tennis rackets, which are currently being offered for sale by the Head company.
But it will definitely be awhile
before you see graphene in TV screens or e-paper.
So let’s summarize—buckyballs were discovered in 1985 and to
date there are no commercial products on the market, but they are getting
close. Nanotubes were discovered
in 1991 and commercial products have only recently entered the market. And graphene, first isolated in 2004, has
not yet found its way into commercial products to a significant extent.
Lesson: it is
really REALLY hard to make money on even the most promising (i.e., coolest) new
technologies. And even if you eventually
succeed, it often takes a really long time—due to the existence of competing
products that are only so-so in terms of performance, but a lot cheaper to
manufacture.
These fantastic carbon molecules effectively illustrate the
position that innovators of revolutionary technologies often find themselves in: they are trying to “push” a product out
the door to buyers who are not yet “pulling.”
Or simply, these are technologies in search of a market. But with some inspired engineering, the
market will come. And then our lives will be a just a little bit better.
Useful references
http://www.pnas.org/content/104/34/13574.full.pdf
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