Between lectures at Saturday’s Undergraduate Nanotechnology Conference, The Varsity sat down with U of T chemistry Professor John Polanyi, a 1986 Nobel Prize winner and the recipient of over thirty honourary degrees.
The Varsity: What is the most exciting part of nanotechnology?
Polanyi: The most exciting thing is the fundamental science. It’s still such an early stage in the history of nanotechnology that it’s the “nano” rather than the “technology” that needs the most work, and that’s where the opportunities lie.
V: What is the current state of emerging nano-devices in Canada and the world?
J.P.: As I understand it, the devices made on the basis of this new science are really very rudimentary. There are creams that contain nano-particles, there are coatings that contain nano-particles, and there are medicines that encapsulate a drug in a nano-envelope. I guess the best simile I can come up with is in the very early days of laser science, which I lived through, the first applications that were thought of was that lasers would be used for drawing straight lines. And they can be, in surveying, but that’s really unimaginative. Then the next thing was drilling holes. The next one after that was cutting car bodies instead of using a welding torch. And then the one after that was cutting a hundred suits at a time instead of cutting one suit at a time. All of these things are possible, but they all are crude applications and the most important applications-which were in communications and navigation, finding out where you are, sending messages-were hardly discussed in the early days at all. I think we’re in just the same stage.
V: What are the challenges facing developing nano-devices today?
J.P.: There are two stages, of a very fundamental sort, in making any nano-device. The first is to assemble it, which you can’t do by hand [because] it costs a million dollars to make one little circle of ten atoms. So you must self-assemble. The only way of building a nano-house, if you like, is to make sticky bricks which are at molecular size, shake them, and have them assemble themselves into a house, a structure that’s useful. That’s step one.
Step two is just as important. The trouble is, because these bricks slither around and form [structures] spontaneously, they also disassemble quite readily. You have to come along with some cement to make that structure permanent. Because what you’re going to do with it [is] throw an electric current through a nano-sized circuit, which is the pattern. An electron hops in, and now the whole circuit’s negatively charged. An electron hops out, and the circuit’s no longer negatively charged. In circuits this small electrons go in individually and leave. Every time an electron arrives, you’ve totally changed its interaction with the outside world-it’s now negatively charged. When electrons leave, the [nano-structure] now adjusts to being neutral. What you’re actually doing is taking this poor fragile self-assembled nano-structure and shaking it furiously and of course, you destroy it. What you have to do is to tether it-you have to hold it with chemical bonds.
V: How do nano-researchers solve this problem?
J.P.: You’ve got to think of ways of stabilizing a nano-structure and that’s where I think chemistry has something to offer. The analogy which I use is the problem of taking a snowflake and putting it on a Xerox machine, and trying to make it permanent so you could have it for all time. The trouble is, in the course of making it permanent you destroy it.
Can you make chemical bonds without ripping apart the nano-structure because the bonds want to form hither and thither all over the place? And the answer is yes, you can. With a chemical reaction induced by light or induced by impinging electrons: those two chemical reactions are so localized that you can imprint without destroying a pattern. And so what we think that we have is the makings of a molecular printing press.
V: Do you have a message for future scientists who hope to break into the nanotech field?
J.P.: It’s always chaotic getting into a field that’s just becoming established, but it’s the most exciting way of spending one’s life, so put up with the chaos and don’t let it distress you.
Scientists really have to struggle to get the freedom to systematically understand something, which is what basic science is, because there’s so much pressure all the time to apply it. The pressure to commercialize in every country is huge and particularly so in this field of nanotech because it’s captured the world’s imagination. But really, there’s so much that one needs to understand before one can start making devices. There’s a great joy in pursuing the fundamental ideas and seeing the generalizations emerge.
If any country or any jurisdiction wants to get the advantage on the pack in nanotechnology they should concentrate on developing their nano-science, then they will see opportunities others have missed.
