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Interview: Technology in a bottle
28 August 2007
Jim Heath talks to Alison Stoddart about the discovery of C60 and his more recent adventures:
|Jim Heath is Elizabeth W Gilloon professor of chemistry at California Institute of Technology, US, and director of the NanoSystems Biology Cancer Center. His current research spans many areas including nanotechnology, molecular electronics and cancer diagnosis. During his graduate studies with Richard Smalley, Jim was the principal student involved in the discovery of C60.|
What prompted you to study nanotechnology?
When I started it wasn't a field. As a graduate student, I was the guy who discovered C60 and that became one of the poster children of nanotechnology. Then, almost by accident I moved into the area. I worked at IBM for a while - synthesising silicon nanoparticles. I guess I fell in love with nanotechnology.
Can you describe the experiment where you saw C60 for the first time?
We were trying to emulate the surface of a carbon star. This was Harry Kroto's idea. We vaporised carbon with a laser in an environment that contained some of the small molecules that surround a carbon star, and then expelled it into a vacuum so we froze the chemistry very quickly. The first time I put carbon in the machine, I saw C60. We had seen interesting clusters of systems before, but this looked unusual. So, even though we were focusing on small clusters, we decided to always monitor C60. As Harry and I worked on the machine, we realised that C60 was a special molecule. I did experiments to show that it wasn't an artefact. I came to the conclusion that it was a closed ball. We had a long debate one day about its structure, we checked out books by Buckminster Fuller and Richard Smalley came up with the structure that night.
It took a while for the scientific community to accept the structure, why was this?
Our experiment was exotic but I thought we had an airtight case. It explained beautifully C60, C70, why we only saw even numbered carbon clusters and why the clusters weren't stable below a certain size. But chemists like to see X-ray crystal structures and NMR spectra and we didn't have these. We only had about 1000 molecules at any given time. But science works by people doubting what you do and pushing you forward. About four years later, many of those who had doubted the structure were working on it.
Were you surprised that C60 became so popular?
C60 was a curiosity until 1991. Then Huffman and Krätschmer made solid-state C60 in gram-sized amounts. In fact, the surprise with C60 was how easy it was to make. Suddenly hundreds of groups worldwide were involved with C60. This explosion was the power of having something interesting plus having something in a bottle. This made me realise that I didn't want to do gas phase chemical physics but I wanted to do something in a bottle.
What are your current research interests?
We work in the area of molecular electronics - making perfect electronic circuits that are macromolecular in dimension. In addition, we can make superconductors and thermoelectrics. A thermoelectric converts a temperature difference into a voltage - like an engine with no moving parts or it does the reverse and acts as a coolant. It turns out that solid-state thermoelectrics have limited uses because they aren't very efficient. If you could make them efficient then the rewards are amazing. We have made materials from oxygen and silicon that are close to the world record for thermoelectrics. These could be used in energy recovery systems in computer chips so wasted energy could be recycled.
I also work with cancer. Our goal is to translate molecular network models of cancer that describe how the disease evolves into tools that can be used in the clinic. We want to be able to do 1000 measurements from a finger prick of blood and at a fraction of a penny per measurement. We have made devices that are used by clinicians but it will be a similar advance as for computer chips. Right now, we can take a finger prick of blood and in a few minutes we do about 20 measurements and we ought to be able to do 40 next year. Our devices have no moving parts, they are made of just glass and plastic, because we want them to be practically free.
These two projects aim to tackle at least pieces of major global problems - energy and world healthcare.
What is your ultimate goal in the cancer project?
Take diabetes - it's a disease which has been transformed by technology over the last few years because you can monitor your glucose levels and take control of the disease. I would be interested to know if you could do this for cancer. It may be possible to detect cancer early on, before clinical signs, and you can always cure it at that point.
What is the secret of being a successful scientist?
It is important to be a good experimentalist, pick the right problems, look across different fields and collaborate with other scientists. When picking a problem, the pathway must be richer than the problem itself - so you have a chance of discovering something interesting along the way. It also helps to recognise when you are lucky. Luck tends to happen to people repeatedly; it's not being lucky, it's being aware when you have been lucky!
The Heath group page at the California Institute of Technolog
Physics and Chemistry of Nanoscale Structures for Molecular Electronics and Biological Applications
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