Last week Daedalus was devising a method of making carbon nanotubes to order, by the electrolytic deposition of C2radicals. His subtle catalytic anode had circular reaction sites as templates, to assemble the radicals into nanotubes. These would grow out from the anode as a close-packed ‘fur’ of parallel nanotubes, which could be stripped off and made into threads and fabrics like any other staple fibre.

He is now generalizing the idea. Already carbon membrane structures can be fabricated by deposition on an alumina template; an anodic template could do so far more controllably. It would assemble whatever carbon structure was defined by the pattern of catalytic sites laid down on it. In particular, if it bore a hexagonal lattice of such sites, it could assemble a carbon honeycomb. Imagine, says Daedalus, a plane hexagonal lattice ‘ground plan’; and imagine each line on this lattice extruding a graphite monolayer sheet upwards out of the plane. Each sheet will touch two others at 120°. If the carbon atoms forming the junctions are bonded together by the tetrahedral sigma bonds found in diamond, the result will be carbon honeycomb — a giant polymeric generalization of the triptycene molecule.

The holes running through a block of carbon honeycomb will have the size defined by the hexagonal catalytic pattern laid down on the anode that forms it. Even the best modern microfabrication methods would produce a catalytic array very coarse on the molecular scale. Finer arrays might be made by cunning surface-crystallization methods, or painstaking assembly by atomic-force microscope. They might even be given two different pore sizes, alternating across the lattice.

So carbon honeycomb could be given a wide range of useful properties. With the finest pores, it would be structurally superb: combining the sepsness of diamond with the oriented strength and toughness of carbon fibre. Larger pores would allow ions and molecules to traverse them, giving novel one-dimensional ionic conductors for batteries, shape-selective catalysts, and molecular sieves and absorbents of vast capacity. The coarser grades would be increasingly tenuous but still very strong, a sort of oriented carbon aerogel. They would be ideal for the insulating interior of laminated panelling and light-weight aerospace components. Filled with epoxy or polyester ‘honey’ and set solid, they would give an outstanding reinforced composite.