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Domain: rice.edu
Stories and comments across the archive that link to rice.edu.
Comments · 754
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Re:How about diamond?
Coating whole circuit boards with diamond might be indeed possible and for less than what you might think. There is a vapor process used for tools where a thin layer of diamond crystal are deposited on the surface over time. Its slow, but there are means to do it. This method may not be ideal for circuit boards yet, it might be ideal for semiconductors when they are manufactured.
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mirrors so far
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More about buckytubes and buckyballsThe hexagonal shape refers to the arrangement of atoms along the surface of the tube. This is because both buckytubes and buckyballs are rolled-up sheets of graphite (rolled into cylinders and spheres respectively). Graphite is a hexagonally-tiled arrangement of sp2-hybridized carbons. Normally this hybridization has two single bonds and one double bond, so you could think of the graphite as a hexagonal tiling with a carbon atom at each vertex, and all the edges in one direction being double bonds, and all the remaining edges being single bonds.
Actually, X ray diffraction studies show that the bond lengths are all identical, so it's really more like each is a 1.666-order bond. This phenomenon, called resonance, also appears in benzene. It is thought to be a quantum superposition of all the possible different ways of arranging the double bonds. (What we call a double bond is actually a superposition of a sigma orbital and a pi orbital.)
The pi orbitals in a sheet of graphite or buckytube all blend together, and depending on the tube's chirality (how the hexagons are oriented relative to the cylindrical axis), this can either allow electrons to move up and down the tube very easily, or it can give semiconductor-like behavior. So a trick to building these kinds of circuits is to find joints that will allow you to join tubes of differing chirality.
Fullerenes are generally quite stable molecules, so it's not too surprising that they describe difficulty in getting current into and out of the buckytube. It turns out that it's not too hard to stick little molecular pieces onto the sides of buckytubes. Al Globus at NASA has done a lot of thinking and simulations relating to applications of nanotubes, including adding teeth to make them function as gears.
Possibly the best source of information on fullerenes is Richard Smalley's Center for Nanoscale Science and Technology at Rice University. Smalley received a Nobel prize for the discovery of fullerenes. The CNST has an interesting-looking PDF document describing the Carbon Nanotechnology Laboratory, and discussing the science of fullerenes and some of the potential applications. Fun stuff.
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More about buckytubes and buckyballsThe hexagonal shape refers to the arrangement of atoms along the surface of the tube. This is because both buckytubes and buckyballs are rolled-up sheets of graphite (rolled into cylinders and spheres respectively). Graphite is a hexagonally-tiled arrangement of sp2-hybridized carbons. Normally this hybridization has two single bonds and one double bond, so you could think of the graphite as a hexagonal tiling with a carbon atom at each vertex, and all the edges in one direction being double bonds, and all the remaining edges being single bonds.
Actually, X ray diffraction studies show that the bond lengths are all identical, so it's really more like each is a 1.666-order bond. This phenomenon, called resonance, also appears in benzene. It is thought to be a quantum superposition of all the possible different ways of arranging the double bonds. (What we call a double bond is actually a superposition of a sigma orbital and a pi orbital.)
The pi orbitals in a sheet of graphite or buckytube all blend together, and depending on the tube's chirality (how the hexagons are oriented relative to the cylindrical axis), this can either allow electrons to move up and down the tube very easily, or it can give semiconductor-like behavior. So a trick to building these kinds of circuits is to find joints that will allow you to join tubes of differing chirality.
Fullerenes are generally quite stable molecules, so it's not too surprising that they describe difficulty in getting current into and out of the buckytube. It turns out that it's not too hard to stick little molecular pieces onto the sides of buckytubes. Al Globus at NASA has done a lot of thinking and simulations relating to applications of nanotubes, including adding teeth to make them function as gears.
Possibly the best source of information on fullerenes is Richard Smalley's Center for Nanoscale Science and Technology at Rice University. Smalley received a Nobel prize for the discovery of fullerenes. The CNST has an interesting-looking PDF document describing the Carbon Nanotechnology Laboratory, and discussing the science of fullerenes and some of the potential applications. Fun stuff.