Category: General

A nearly nano-free week in California

I’ve been in Santa Barbara, CA, this week, finding out that traveling with two small children doesn’t leave much time for writing about nanotechnology or anything else. The occasion for the visit is the 65th birthday of Ed Kramer, a distinguished materials scientist at University of California Santa Barbara; it’s a part social, part scientific event bringing together his past and present graduate students, postdocs, and collaborators to celebrate his career so far and to thank him for his huge influence on our scientific careers (I was a postdoc with him between 1987 and 1989 at Cornell; these were two tremendously productive, educational and enjoyable years).

The scientific part of the proceedings consisted of a meeting with talks by his former students and collaborators. There were many nano-science luminaries around and much great stuff talked about; among those talking were Ned Thomas, director of the Institute of Soldier Nanotechnology at MIT, talking about photonic crystals, Herbert Hui with a beautifully lucid description of exactly why gecko feet are so sticky, Chris Ober from Cornell talking about new resist materials for making sub-30nm features, as well as rapid 3-d prototyping at the micron-scale using two-photon photo-polymerisation, and lots of other good stuff too.

Strangely, though, there was little mention of the nano word. Even the most distinguished of our number, faced with giving a talk in front of Ed, felt a bit like a graduate student again, in awe of the great man. Everyone has worked with him is in agreement that he’s someone who expects a lot from their students, who is quick to appreciate good work, and outstanding at standing back and making sure his collaborators get all the credit they deserve and more. But he’s got a low tolerance threshold for hype and fashion and we all knew that the way to get his approval is by telling a solid science story without any sweeping claims for grander significance.

I think we were all overcompensating. I asked Ned Thomas how he felt about now being very publicly labeled as a nanotechnologist, rather than as a polymer physicist. He thought there was a real difference; the science he did was rather similar, learning how to create nanostructures in polymers by self-assembly, but the focus had changed. It wasn’t so much that all his work now was focused on an immediate application, but the possibility of an eventual application provided a much more powerful steer on the direction of his work than was the case in the past. I think this rings true as a description of one of the changes in the sociology of science that nanotechnology as a concept has brought about.

Drexler responds

This morning brought a somewhat tetchy email from K. Eric Drexler, not entirely happy about my article in Physics World, The future of nanotechnology. There were three main complaints:

1. That he, Drexler, could not be held responsible for the “ridiculous artist’s concepts” that have become associated with his work. Thus my criticism of the nanosubmarine illustration isn’t a fair criticism of MNT. Actually, I have some sympathy with his predicament on this, in that I’m sure that the elementary errors that show up in the particularly silly image I chose wouldn’t be there if Drexler had had anything to do with it. Nonetheless, my criticism of these images does make one important point very clear – you shouldn’t expect macroscopic engineering design concepts to apply to directly to the nanoworld. Is this a fair criticism of MNT? I think it is – to quote from the preface of Nanosystems; “Molecular manufacturing applies the principles of mechanical engineering to chemistry”.

2. Next he argues that my statement that “Strong surface forces may make the moving parts of a NEMS device stick together and seize up” reflects a lack of study of the appropriate section of Nanosystems, chapter 10, which argues that very low friction is to be expected between atomically smooth diamond surfaces. It’s worth noting first of all that this statement in my article isn’t actually directed at MNT at all, but at top-down NEMS. Nonetheless, I do believe that the discussion in Nanosystems does substantially underestimate the problems of friction and dissipation at the nanoscale. This is a rather technical discussion, which I will enlarge on at a later time.

3. Finally, he objects that I have not proved my central contention, that biology is highly optimised for the nanoscale, pointing out that biology hasn’t been able to explore the space of non-aqueous molecular machine systems. This gets to the heart of the argument of Soft Machines. A crucial, though obvious, point, is that it only makes sense to talk about optimisation in the context of a particular environment, and what is optimised for ambient operation at 300 K in the presence of water is not the same as what is optimised for ultra-high vacuum at a temperature of 3 K. I wouldn’t exclude the possibility that MNT would work at 3 K in UHV, but I think that what works in ambient conditions is much more interesting, if only because medicine is likely to be such an important application of nanotechnology.

Soft Machines weblog

Welcome to the Soft Machines weblog, which I hope will be the more interactive part of the overall Soft Machines website. One purpose of the website is to publicise my book, of course, but I would also like to make it a useful resource on nanotechnology. I’m not going to try to be comprehensive – there are many other good resources on the internet and elsewhere. Instead I’ll give a personal view, from the perspective of a scientist working in the area, of what I think is really interesting. I’ll also use the web-site if I need to amplify points in the book, to report feedback to the book and my response to it, and if necessary to update and correct it. Early drafts of this material will probably make their first appearance on this weblog.