Category: General

Nanoscale ball bearings or grit in the works?

It’s all too tempting to imagine that our macroscopic intuitions can be transferred to the nanoscale world, but these analogies can be dangerous and misleading. For an example, take the case of the buckyball bearings. It seems obvious that the almost perfectly spherical C60 molecule, Buckminster fullerene, would be an ideal ball bearing on the nanoscale. This intuition underlies, for example, the design of the “nanocar”, from James Tour’s group in Rice, that recently made headlines. But a recent experimental study of nanoscale friction by Jackie Krim, from North Caroline State University, shows that this intuition may be flawed.

The study, reported in last week’s Physical Review Letters (abstract here, subscription required for full article), directly measured the friction experienced by a thin layer sliding on a surface coated with a layer of buckminster fullerene molecules. Krim was able to directly compare the friction observed when the balls were allowed to rotate, with the situation when the balls were fixed. Surprisingly, the friction was higher for the rotating layers – here the ball-bearing analogy is seductive, but wrong.

In Seville

I’ve been in Seville for a day or so, swapping the Derbyshire drizzle for the Andalucian sun. I was one of the speakers in a meeting about Technology and Society, held in the beautiful surroundings of the Hospital de los Venerables. The meeting was organised by the Spanish writer and broadcaster Eduardo Punset, who also interviewed me for the science program he presents on Spanish TV.

As well as my talk and the TV interview, I also took part in a panel discussion with Alun Anderson, the former editor-in-chief of New Scientist. This took the form of a conversation between him and me, with an audience listening in. I hope they enjoyed it; I certainly did. As one would imagine, Anderson is formidably well- informed about huge swathes of modern science, and very well-connected with the most prominent scientists and writers. Among the topics we discussed were the future of energy generation and transmission, prospects for space elevators and electronic newspapers, Craig Venter’s minimal genome project, and whether we believed the premise of Ray Kurzweil’s most recent book, ‘The Singularity is Near’. Alun announced he would soon be appearing on a platform with a Ray Kurzweil’s live hologram, or thereabouts. However he did stress that this was simply because the corporeal Kurzweil couldn’t get to the venue in person, not because he has prematurely uploaded.

Lost comments

I apologise that a number of legitimate comments in recent days have been stopped by my spam filters – I’ve just rescued 6 of these from the moderation queue, where I had previously overlooked them amidst 519 spam comments. If you do make a comment which doesn’t appear (and this is most likely to happen to relatively long messages with lots of external links) you might want to alert me to this with a shorter comment. Anyway, my apologies to Brian Wang, Reza Fathollahzadeh, Moderate Transhumanist, NanoEnthusiast, sa. jafari and Michael Anissimov.

On my nanotechnology bookshelf

Following my recent rather negative review of a recent book on nanotechnology, a commenter asked me for some more positive recommendations about books on nanotechnology that are worth reading. So here’s a list of nanotechnology books old and new with brief comments. The only criterion for inclusion on this list is that I have a copy of the book in question; I know that there are a few obvious gaps. I’ll list them in the order in which they were published:

Engines of Creation, by K. Eric Drexler (1986). The original book which launched the idea of nanotechnology into popular consciousness, and still very much worth reading. Given the controversy that Drexler has attracted in recent years, it’s easy to forget that he’s a great writer, with a very fertile imagination. What Drexler brought to the idea of nanotechnology, which then was dominated, on the one hand by precision mechanical engineering (this is the world that the word nanotechnology, coined by Taniguchi, originally came from), and on the other by the microelectronics industry, was an appreciation of the importance of cell biology as an exemplar of nanoscale machines and devices and of ultra-precise nanoscale chemical operations.

Nanosystems: Molecular Machinery, Manufacturing, and Computation , by K. Eric Drexler (1992). This is Drexler’s technical book, outlining his particular vision of nanotechnology – “the principles of mechanical engineering applied to chemistry” – in detail. Very much in the category of books that are often cited, but seldom read – I have, though, read it, in some detail. The proponents of the Drexler vision are in the habit of dismissing any objection with the words “it’s all been worked out in ‘Nanosystems'”. This is often not actually true; despite the deliberately dry and textbook-like tone, and the many quite complex calculations (which are largely based on science that was certainly sound at the time of writing, though there are a few heroic assumptions that need to be made), many of the central designs are left as outlines, with much detail left to be filled in. My ultimate conclusion is that this approach to nanotechnology will turn out to have been a blind alley, though in the process of thinking through the advantages and disadvantages of the mechanical approach we will have learned a lot about how radical nanotechnology will need to be done.

Molecular Devices and Machines : A Journey into the Nanoworld , by Vincenzo Balzani, Alberto Credi and Margherita Venturi (2003). The most recent addition to my bookshelf, I’ve not finished reading it yet, but it’s good so far. This is a technical (and expensive) book, giving an overview of the approach to radical nanotechnology through supramolecular chemistry. This is perhaps the part of academic nanoscience that is closest to the Drexler vision, in that the explicit goal is to make molecular scale machines and devices, though the methods and philosophy are rather different from the mechanical approach. A must, if you’re fascinated by cis-trans isomerisation in azobenzene and intermolecular motions in rotaxanes (and if you’re not, you probably should be).

Bionanotechnology : Lessons from Nature, by David Goodsell (2004). I’m a great admirer of the work of David Goodsell as a writer and illustrator of modern cell biology, and this is a really good overview of the biology that provides both inspiration and raw materials for nanobiotechnology.

Soft Machines : Nanotechnology and Life, by Richard Jones (2004). Obviously I can’t comment on this, apart from to say that three years on I wouldn’t have written it substantially differently.

Nanotechnology and Homeland Security: New Weapons for New Wars , by Daniel and Mark Ratner (2004). I still resent the money I spent on this cynically titled and empty book.

Nanoscale Science and Technology, eds Rob Kelsall, Ian Hamley and Mark Geoghegan (2005). A textbook at the advanced undergraduate/postgraduate level, giving a very broad overview of modern nanoscience. I’m not really an objective commentator, as I co-wrote two of the chapters (on bionanotechnology and macromolecules at interfaces), but I like the way this book combines the hard (semiconductor nanotechnology and nanomagnetism) and the soft (self-assembly and bionano).

Nanofuture: What’s Next For Nanotechnology , by J. Storrs Hall (2005). Best thought of as an update of Engines of Creation, this is a an attractive and well-written presentation of the Drexler vision of nanotechnology. I entirely disagree with the premise, of course.

Nano-Hype: The Truth Behind the Nanotechnology Buzz, by David Berube (2006). A book, not about the science, but about nanotechnology as a social and political phenomenon. I reviewed in detail here. I’ve been referring to it quite a lot recently, and am increasingly appreciating the dry humour hidden within its rather complete historical chronicle.

The Dance of Molecules : How Nanotechnology is Changing Our Lives , by Ted Sargent (2006). Reviewed by me here, it’s probably fairly clear that I didn’t like it much.

The Nanotech Pioneers : Where Are They Taking Us?, by Steve Edwards (2006). In contrast to the previous one, I did like this book, which I can recommend as a good, insightful and fairly nanohype-free introduction to the area. I’ve written a full review of this, which will appear in “Physics World” next month (and here also, copyright permitting).

Which nation’s scientific output is rising fastest?

China, you might say, but you’d be wrong, according to a study of world rankings in science published recently by the UK government (latest DTI study into the outputs and outcomes from UK science – 920 kB PDF). This looks at a variety of input and output measures to construct a fairly complete picture of the distribution of scientific activity and impact around the world. Notwithstanding the surprising answer to my trick question (revealed at the end of this post), this report confirms the rapid growth of China as scientific power, the lessening of the formerly unchallenged dominance of the USA, and (from a parochial perspective) the rather strong performance of the UK, which spends less on research and has fewer researchers than its competitors, but nonetheless in comparison produces proportionately more science with a greater impact.

It’s in spending on science research that the rise of China is most obvious – in real terms (adjusted for purchasing power parity) China’s research spend has increased four-fold in the last decade; it now exceeds that of all other individual countries except USA and Japan, and has reached half the European Union total. In terms of output of scientific publications, China now has a 5% world share, up by a factor of three in the last decade, and now greater than France. Again, in terms of individual nations the USA still leads by this output measure, with almost exactly one third of world output, but the European Union nations taken together have now outstripped the USA, with 37.9% of publications. The UK, at just less than 9%, is the second placed individual nation, having recently overtaken Japan. If we took the Asia-Pacific group of China, Korea, Taiwan and Singapore together they would account for 10% of world output.

What about quality and impact? Here the USA still has a clear lead; taking as a measure of world impact the share of the most highly cited papers (taken as the top 1% in each discipline) puts the USA in the lead with 61%, while the UK outperforms its volume share with 13% of highly cited papers. China still underperforms on this measure but the gap is closing, and is likely to close further as citation counts are a lagging indicator – it takes some years for spending on science to translate, first into publication outputs, and only later into citations of those papers by other workers.

The country whose output of scientific publications has increased the most over the last decade is Iran, whose output has increased by a factor of ten, albeit from a low base (China’s increased by a factor of three, the second fastest rate of growth). It will be interesting to see, in the light of recent political developments, whether Iran’s good performance will continue.

Forthcoming nano events in Sheffield

A couple of forthcoming events might interest nano-enthusiasts at a loose end in South Yorkshire in the next few weeks. Next Monday at 7pm, there’s a public lecture as part of National Science Week in the Crucible Theatre, called “A robot in the blood”. In it, my colleagues Tony Ryan and Noel Sharkey, will discuss what a real medical nanobot might look like. Both are accomplished public performers – Tony Ryan is a chemist (with whom I collaborate extensively) who gave the Royal Institution Christmas lectures a couple of years ago, and Noel Sharkey is an engineer and roboticist who regularly appears in the TV program “Robot Wars”.

Looking further ahead, on Monday April 3rd there is a one day meeting about “Nanotechnology in Society: The wider issues”. This will involve talks from commentators on nanotechnology from different view points, followed by a debate. Speakers include Olaf Bayer, from the campaigning group Corporate Watch, Jack Stilgoe, from the public policy thinktank Demos, Stephen Wood, co-author (with me and Alison Geldart) of the Economic and Social Reseach Council report “The Social and Economic Challenges of Nanotechnology”, and Rob Doubleday, a social scientist working in the Cambridge Nanoscience Centre. The day is primarily intended for the students of our Masters course in Nanoscale Science and Technology, but anyone interested is welcome to attend; please register in advance as described here.

Another draft nano-taxonomy

It’s clear to most people that the term nanotechnology is almost impossibly broad, and that to be useful it needs to be broken up into subcategories. In the past I’ve distinguished between incremental nanotechnology, evolutionary nanotechnology and radical nanotechnology, on the basis of the degree of discontinuity with existing technologies. I’ve been thinking again about classifications, in the context of the EPSRC review of nanotechnology research in the UK; here one of the things we want to be able to do is to be able to classify the research that’s currently going on. In this way it will be easier to identify gaps and weaknesses. Here’s an attempt at providing such a classification. This is based partly on the classification that EPSRC developed last time it reviewed its nanotechnology portfolio, 5 years ago, and it also takes into account the discussion we had at our first meeting and a resulting draft from the EPSRC program manager, but I’ve re-ordered it in what I think is a logical way and tried to provide generic definitions for the sub-headings. Most pieces of research would, of course, fit into more than one category.

Enabling science and technology
1. Nanofabrication
Methods for making materials, devices and structures with dimensions less than 100 nm.
2. Nanocharacterisation and nanometrology
Novel techniques for characterisation, measurement and process control for dimensions less than 100 nm.
3. Nano-modelling
Theoretical and numerical techniques for predicting and understanding the behaviour of systems and processes with dimensions less than 100 nm.
4. Properties of nanomaterials
Size-dependent properties of materials that are structured on dimensions of 100 nm or below.
Devices, systems and machines
5. Bionanotechnology
The use of nanotechnology to study biological processes at the nanoscale, and the incorporation of nanoscale systems and devices of biological origin in synthetic structures.
6. Nanomedicine
The use of nanotechnology for diagnosing and treating injuries and disease.
7. Functional nanotechnology devices and machines
Nanoscale materials, systems and devices designed to carry out optical, electronic, mechanical and magnetic functions.
8. Extreme and molecular nanotechnology
Functional devices, systems and machines that operate at, and are addressable at, the level of a single molecule, a single atom, or a single electron.
Nanotechnology, the economy, and society
9. Nanomanufacturing
Issues associated with the commercial-scale production of nanomaterials, nanodevices and nanosystems.
10. Nanodesign
The interaction between individuals and society with nanotechnology. The design of products based on nanotechnology that meet human needs.
11. Nanotoxicology and the environment
Distinctive toxicological properties of nanoscaled materials; the behaviour of nanoscaled materials, structures and devices in the environment.

All comments gratefully received!

From the gallery

For no particular reason other than it is a really nice image, here’s a picture from the Sheffield Polymer Physics Group. It’s an AFM image of a thin film of a block copolymer – a molecule with a long section that can crystallise (poly ethylene oxide), attached to a shorter length of a non-crystallisable material (poly vinyl pyridine). What you can see is a crystal growing from a screw dislocation. The steps have a thickness of a single molecule folded up a few times.

AFM image of a block copolymer growing from a screw dislocation

Image width 20 microns. Image by Dr Cvetelin Vaslilev, image post-treatment by Andy Eccleston.

Scenarios for the future of transport

The UK government established a new horizon-scanning unit in its Office and Science and Technology a few years ago, and this has now issued its first report. This takes a look at likely scenarios for transport infrastructures over the next fifty years, but since transport and communications are so central to our economy these scenarios form a fairly comprehensive look at how new technology might change the way we live. In particular, they cover three big questions about technology and the future:

  • Where will the energy that currently underwrites our lifestyle in the developed world come from?
  • How will we exploit the growing amount of information processing and communication power we will have at our disposal?
  • Will the world carry on its trend to centralisation in manufacturing and energy generation, or will we see a switch to increasingly decentralised modes of production?

    • The web-site has links to lot of excellent material, including many interesting, specially commissioned background papers, but perhaps the most interesting things are the Project overview (54 page PDF), and the Scenarios (89 page PDF). The latter bring the subject to life with four plausible, but highly contrasting, scenarios for how things might turn out.

    The techno-optimist’s scenario is called “Perpetual motion”. Here it’s assumed that technology has managed to overcome the problems of sustainable energy with some combination of the hydrogen economy, nuclear fuels, coal and carbon sequestration. Everything and everyone is plugged in to the information grid, and the major problem the world faces is workplace stress. There’s a green nirvana too: “Urban colonies” imagines a future of sustainable urbanisation, where personal transport is discouraged by heavy taxation. Energy comes from microgrids, there is universal recycling and reuse. People are prosperous, but the economy revolves around fewer goods and more services. Iin short, it’s a vision of the future in which everywhere looks like Copenhagen, rather than Seoul. But, on the principle that the statistically most accurate way of predicting the weather tomorrow is to look out of the window today, what is considered the most likely scenario is called “Good intentions”. This is a world in which hard decisions have been put off until too late. Transport is both highly congested and highly priced; there’s been some progress with biofuels but accelerating climate change is leading to increasingly frequent weather disasters. Both prosperity and personal freedom are compromised.

    Techno-optimists think that the accelerating pace of technological advances will determine how the world changes, while green-tinged social liberals believe that the future can be deliberately shaped by human, democratic values. There is a third, much uglier, possibility; that we will be unable to prevail over overwhelming societal strains imposed by external shocks. This is the world of the most pessimistic scenario, “Tribal trading”. Here an early end to the era of cheap energy has stripped the veneer from our globalised world. A decline in oil production has led to spiralling oil prices. Economic depression has ended with the near-complete collapse of world and national financial systems, with resource wars and environmental disasters adding to the gloom. It’s a world of walls and borders and vegetable gardens, in which the 90’s experience of Cuba offers some of the best coping strategies. Some technology survives, and with travel over even modest distances prohibitively difficult and expensive, robust communications are more important than ever. For advice, we’re directed to the poet Gary Snyder:

    “What is to be done? Learn to be more self-reliant, reduce your desires, and take care of yourself and your family”.

    Throbbing gels

    This month’s edition of Nano Letters includes a paper from our Sheffield soft nanotechnology group (Jon Howse did most of the work, assisted by chemists Colin Crook and Paul Topham and beam line scientists Anthony Gleeson and Wim Bras, with me and Tony Ryan providing inspiration and/or interference) demonstrating the direct conversion of chemical energy to mechanical energy at the single molecule level. This is a development of the line of work I described here. Our idea is to combine a macromolecule which changes size in response to a change in the acidity of its surroundings with a chemical reaction which spontaneously leads to an oscillation in the acidity, to get a cyclic change in size of the polymer molecule. The work is summarised in a piece on nanotechweb.org.