Deep down in the cold

A picture’s worth a thousand words. Researchers at IBM Zurich have imaged a carbon nanotube in-situ.

This is important. While it’s been possible to image individual atoms for many years, the imaging of anything more complex is far harder, simply because of the hue and cry of neighbouring atoms fuzzing it all up. A diamond surface is do-able, but imaging a single molecule, with all its structure intact (look, you can even see the wispy h-bonds at top and bottom, where stray hydrogen atoms have capped off nonvalent danglers) – well, that’s harder.

It’s important in a philosophical way too. It demonstrates that all the bump and grind of room-temperature atomic physics doesn’t prevent complex structures being isolated, studied, and – maybe soon – built. A carbon atom was added to a surface by an AFM tip some years back and stayed there, proving it’s possible to assemble whole molecules bit-by-bit, at least in principle.

Even if Drexlerian (“dry”) nanotechnology is never able to handle anything more complex than the simplest part of the periodic table – atoms like carbon and silicon, nitrogen and oxygen and chlorine – that’s still amazing. Because the valencies of carbon (and to some extent silicon) that let it form into a huge variety of structures are all we may need. Molecular assembers, little gems of structured carbon, will be built. The first few painstakingly, with AFM tips and miniscule success rates, will be simple, able to do no more than abstract a carbon atom. The second generation will be a little better, able to manipulate two atoms and join them together with a precise covalent link. And the third generation will build the fourth.

From there we’ll build billions upon billions, antlike carbon armies each programmed for a few simple tasks like finding stray carbon atoms and forming them into tubes. Imaged like the above, you’d see an intricate framework of nanotube scaffolding, rods and levers pushing back and forth, carbon worm gears rotating ceaselessly at millions of rpm. And in the gaps and spaces between – little pockets of hard vacuum in our messy atmosphere, unwanted organics stuff locked out by the laws of physics – other parts would be assembled.

When two complementary machines “met”, shaped to interact only on contact, the two parts they’d assembled would be released and locked together. Then the cycle repeats, and over time (a few seconds) a larger machine would emerge from the carbon cloud, a more complex machine designed to do something useful like filter clean H2O from a mole of mud.

And you’d build them not one by one, but in bucketloads of billions that could join themselves together into macroscale cubes and panes that could do useful work. A cellophane sheet unrolled over a hundred square metres of desert that in a week would mine the sand below and extrude above… a house. Or a web of thin pipelines leading from the surface to the seabed, safely sequestering greenhouse gases back where they came from.

And as for desktop computing – the difference between electronic and mechanical breaks down at this scale. Nanoscale computers, built on exchanged electrons or stabbing carbon rods, will be Turing their way through your work far faster and cheaper than today. Masses of solid-state silicon – not in today’s crude blocks, but in perfectly precise ranks of atoms structured into molecular-scale circuitry: logic gates of a few atoms, wires of wispy carbon nanotubes, single-molecule capacitors and resistors cramming today’s primitive processors into a speck of dust. A skyscraper’s worth of datacentre, recontextualised as a single complex molecule.

At some of the Stateside nanotech conferences I visited years back, the conversation often turned to cheeseburgers. Imagine a microwave-oven sized machine that not only warmed your lunch, but built it, assembling the tangled chains of protein and carbs from their component atoms. I don’t believe that’ll happen: there’s no point making a burger in the machine phase, any more than you’d build a car from origami paper. There are just easier ways to do it.

But as for the hard shapes and snap-together parts of engineering – the photo above makes that almost a dead cert. First comes the photographing; next comes the building. The picture above isn’t a work of art. It’s a blueprint.

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