A good way of assessing whether a writer knows what they are talking about when it comes to nanotechnology is to look at what they say about quantum mechanics. There’s a very widespread view that what makes the nanoscale different to the macroscale is that, whereas the macroscale is ruled by classical mechanics, the nanoscale is ruled by quantum mechanics. The reality, as usual, is more complicated than this. It’s true that there are some very interesting quantum size effects that can be exploited in things like quantum dots and semiconductor heterostructures. But then lots of interesting materials and devices on the nanoscale aren’t ruled by quantum mechanics at all; for anything to do with mechanical properties, for example, nanoscale size effects have quite classical origins, and with the exception of photosynthesis almost nothing in bionanotechnology has anything to do with quantum mechanics. Conversely, there are some very common macroscopic phenomena that simply can’t be explained except in terms of quantum mechanics – the behaviour of electrical conductors and semiconductors, and the origins of magnetic materials, come immediately to mind.
Here’s a fairly typical example of misleading writing about quantum effects: The ���novel properties and functions��� are derived from ���quantum physics��� effects that sometimes occur at the nanoscale, that are very different from the physical forces and properties we experience in our daily lives, and they are what make nanotechnology different from other really small stuff like proteins and other molecules. This is from NanoSavvy Journalism, an article by Nathan Tinker. Despite its seal of approval from David Berube, this is very misleading, as we can see if we look at his list of applications of nanotechnology and ask which depend on size-dependent quantum effects.
…right so far; the use of things like semiconductor heterostructures to make quantum wells certainly does depend on exploiting qm…
…here we are talking about systems with high surface to area ratios, self-assembled structures and tailoring the interactions with biological macromolecules like proteins, all of which has nothing at all to do with qm…
…if we are talking liposomes, again we’re looking at self-assembly. To explain the transparency of nanoscale titania for sunscreen, we need the rather difficult, but entirely classical, theory of Mie scattering.
The list goes on, but I think the point is made. All sorts of interesting and potentially useful things happen at the nanoscale, only a fraction of which depend on quantum mechanics.
On the opposition side, the argument about the importance of quantum mechanical effects is pressed into service as a reason for anxiety; since everyone knows that quantum mechanics is mysterious and unpredictable, it must also be dangerous. I’ve commented before on the misguided use of this argument by ETC; here’s the Green Party member of the European Parliament, Caroline Lucas, writing in the Guardian: The commercial value of nanotech stems from the simple fact that the laws of physics don’t apply at the molecular level. Quantum physics kicks in, meaning the properties of materials change. This idea of the nanoscale as a lawless frontier in which anything can happen is rather attractive, but unfortunately quite untrue.
Of course, the great attraction of quantum mechanics is all the fascinating, and usually entirely irrelevant, metaphysics that surrounds it. This provides a trap for otherwise well-informed business people to fall into, exposing themselves to the serious danger of ridicule from TNTlog, (whose author, besides being a businessman, has had the unfair advantage of having a good physics education).
I know that it’s scientists who are to blame for this mess. Macroscopic=classical, nanoscale=quantum is such a simple and clear formula that it’s tempting for scientists communicating with the media and the public to use it even when they know it is not strictly true. But I think it’s now time to be a bit more accurate about the realities of nanoscale physics, even if this brings in a bit more complexity.