Posted: June 11, 2007

Revolutionary nanotechnology: wet or dry?

(Nanowerk News) The IEEE Spectrum blog has an entry today titled "Revolutionary nanotechnology: wet or dry?": "Somewhere along the line, the advocates for molecular nanotechnology (MNT) seem to have lost interest in actually seeing molecular manufacturing come to pass if it meant that the concepts of the mechanically engineered approach (Dry) are abandoned in favor of a biologically engineered method (Wet)."
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The MNT community has been striving over the past six years to bring the focus of nanotechnology back to molecular manufacturing—or “radical nanotechnology” or “revolutionary nanotechnology” after being usurped in attention and funding by the nanomaterials initiative, exemplified by the National Nanotechnology Initiative in the US.
Back in 1986, about the only people talking about nanotechnology was the venerable Foresight Institute (by venerable, I mean old in relative terms).
Of course, there may have been a few who could quote Norio Taniguchi’s 1974 paper “On the basic concept of ‘Nano-Technology’”, or those who could drop Feynman’s 1959 lecture “There’s plenty of room at the bottom” into their polite conversation. But by and large there was the Foresight Institute created on the heels of K. Eric Drexler’s “Engines of Creation” that stood as a lone voice promoting nanotechnology.
Then came the National Nanotechnology Initiative (NNI) and everything changed. After 5 years of development, the NNI was funded and launched in 2001. And, well, the lone voice suddenly got drowned out.
The buzz about nanotechnology was no longer just about universal assemblers (robot-like machines) that would lead to a day of “table-top factories” but was about how materials on the nanoscale exhibited interesting functionalities that could enable new products, like stain-resistant pants.
Stain-resistant pants clearly don’t have the sex appeal of a factory on a table top that could make anything you wanted just by pressing the button: “Ferrari”. But there you have it. The dialogue had been transformed in large part because of money.
The money started flowing into research for exploiting this nanoscale material science from government and industry that saw they could create new products and markets.
So how do you get the discussion back to your direction, well it goes something like this: “Okay, okay, but you guys are talking about ‘evolutionary nanotechnology’, we’re talking about ‘revolutionary nanotechnology’.”
The tag ‘evolutionary nanotechnology’ implies that the new brand of nanotechnology is just an incremental step in fields such as surface and material science and colloid science. If you ask a chemist or chemical engineer, they might even boast: “Nanotechnology?! This is just advanced chemistry.”
That’s how the proponents of “revolutionary nanotechnology” describe “evolutionary nanotechnology”. But what is this “revolutionary nanotechnology”?
Well, revolutionary nanotechnology can be loosely defined as we humans being able to make macro-scale things atom-by-atom or molecule-by-molecule, with the assitance of computers designing and then assembling materials and structures by placing atoms exactly where we want them to go. The proof we have that this can be done, or so the argument goes, is that if nature can do it, so can we . Of course, nature has had a few billion years to perfect this little feat, but we’ve got science and technology on our side.
The first method proposed for designing and building these structures atom-by-atom was what is often termed the Drexlerian vision in his book “Nanosystems: Molecular Machinery, Manufacturing and Computation”.
This mechanosynthesis approach, often termed molecular nanotechnology (MNT), can be described as mechanical engineering meets the nanoscale. The machinery described involves gears and motors, just like you would find in a large-scale factory.
But mechanical engineering of the macroscale faces some fundamental problems when shrunk down to the nanoscale like Brownian motion or thermal noise that make building these nanoscale gears and motors to the tight tolerances required problematic.
Richard Jones, a professor of Physics at Sheffield University in the UK, and author of the book, Soft Machines, has asked the proponents of this MNT vision to address these issues in Six Challenges for Molecular Nanotechnology.
But Professor Jones, according to his blog, has not received any response to his challenges from the MNT community.
What is odd about this debate (if indeed there were one) is that Professor Jones does believe that a “revolutionary nanotechnology” or “radical nanotechnology” should be pursued, and even argues that its possibility is confirmed by nature, just as the MNT community does.
But his more biologically oriented approach is that of using and working with nature rather than trying to work against it. His point is made clear at a debate held at Nottingham University in 2005.
“My argument is that although biology is an existence proof for radical nanotechnology it is not necessarily an existence proof for Drexler’s particular vision of nanotechnology as we shall now see. The reason is this: biological machines are not actually mechanical…
“You’ve got these different design philosophies: one of which is the mechanical engineering approach. I’m not saying that Drexler is someone who doesn’t know physics, of course he does. He talks about Brownian motion, he talks about surface forces. The philosophy of the mechanical engineering approach is to say, I know these things are there, they are problems, let’s try to design around them, let’s use really stiff materials to avoid the problem of Brownian motion. In contrast, biology doesn’t design around it, it actually exploits it. You can see this through the efficiency of biological machines.”
So, revolutionary nanotechnology: wet or dry? While it seems the established MNT community is attempting to bring the term “nanotechnology” back into their own personal dominion by promoting this distinction between “evolutionary” and “revolutionary” nanotechnology, they are loath to have that vision of a “revolutionary nanotechnology” be anything other than the “hard” mechanosynthesis proposed by Drexler over 25 years ago.
What is curious about all this is that a quick perusal of the Foresight Institute’s blog Nanodot provides a number of examples of research and papers on biologically inspired “nanobots” and “nanotechnology” and little in experimentation on mechanosynthesis nanotechology: "Meet the Nubot: DNA nanotechnology robots" and "Nature’s nanotechnology motors to inspire future machines."
But despite the growing research, despite the direction science is continuing to go, there is loyal adherence to the original precepts of mechanosynthesis “revolutionary nanotechnology”.
This ideological pushback is perplexing. Why is not science the guiding principle if the real aim is to be able to produce macroscale products that eliminate waste and make possible radical new products for energy and healthcare applications?
Source: IEEE Spectrum (posted by Dexter)
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