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Fun With Nanotechnology Advances
wieselwerkstatte sent us a link to a Nature article that talks about the possibilty for self-soldering molecular wires. In related news, demon-cw sent us a C't story about .2 buckyballs that they are using to create nanotubes. Use the fish for those who don't speak German.
Smaller is not possible
Michaela Simon 02.11.2000
A carbon tube with a diameter of 4*10^-10m (= 0.4nm)
The Nobel Price 1996 for Chhemistry was awarded for the discovery of a soccer ball - a very small one though. The "Buckyball" only consists of 60 carbon atoms. Its synthesis and detection awarded Robert F. Curl, Harold W. Kroto und Richard E. Smalley the price.
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The atoms of this molecule are placed exactly like the sextangular leather patches of a soccer ball. With this C60 is another modification of carbon among graphite and diamond. Until now quite a number of carbon spheres of different sizes have been found. The smallest one of this Fullerenes called class of carbon molecules - the C20 - was just recently described in the magazine Nature (2000, 407, S.60-63.).
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A few years ago there was quite an euphoria about C60 and relatives, and its applications in various areas of science was lively discussed (e.g. superconduction and HIV proteasis inhibition). Even if today anyone can order C60 in chemistry wholesale shops ($500 per gramm) there never was a real technological breakthrough.
The latter is hoped to come with carbon nanotubes - molecules formed like tubes that consist exclusively of carbon (like C60). These tubes were discovered 1991 by the Japanese researcher Sumio Iijima. Nanotube research started as offspring of Fullerene chemistry and is on its best way to surpass it.
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Carbon nanotubes consist of concentric graphite shells - between one and fifty of them which gives a diameter of 1-50nm. But nanotubes can be up to a millimetre in length - and it is this anisotropy that is of importance for applications. Fibers made of nanotubes are said to have an enormous tensile strength (100times stronger than steel with 1/16th of steel's weight). The interior of these tubes can be filled with various material (e.g. hydrogen) - even chemical reactions are possible within these miniature test-tubes.
Because of teir special electronic properties these tubes could become an important part of future nano technology.
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In today's issue of Nature two research groups from Hongkong and Japan report independently about the(ir) world smallest nanotube (Nature, 2000, 408, S. 50 und S. 51). It only has a radius of 0.2 nm (nanometers, 2*10^-10m). According to theory scientists this radius is the ultimate as smaller tubes won't be stable any more.
The extreme curvature of the carbon shells creates unusual physical properties: along the axis these tubes a metal-like conductivity is postulated. Further properties of this smallest of all nanotubes have to be researched, but be prepared for suprprise.
Nanotechnology is going to destroy the pathetic United States, as well as every other country in this world? Why, you ask? Because the technology has the potential to:
1) Make humans immortal (or pretty close to it)
2) Grant humans the use of 'unlimited resources'
3) The ability to learn things much quicker
Do you honestly believe that a military or politician(s) will be able to keep this technology to themselves? That is absolutely impossible, considering the people with the real brains aren't even in the military or the government, and if the government decided to keep the technology for itself, these 'people' would just create a non-commercial nanotechnology which they would release to everyone, in the name of rebellion against a government that never worked properly or efficiently in the first place.
The United States may be eager for Nanotech, but the truth is they are also horrified of it. Why? Here is the truth that the morons in our governent don't want you to know: NANOTECHNOLOGY WILL BRING THE ABSOLUTE DEATH OF DEMOCRACY AND CAPITALISM. Wow, it looks like they have every right to be afraid. No more government - no more money system! WHAT ARE WE GOING TO DO!?
That answer is simple - we are going to become Gods, and there is NO ONE alive or dead who can stop this from happening.
'Death to the pathetic United States, and death to Democracy and Capitalism!! Good riddance!'
That is not what they mean. When they say that the wires are self soldering and that when they ramp the voltage the conductivity drops, they don't mean that the wires melt and then fuse together and remelt and break apart.
What happens is the two gold "wires" are joined together by a long molecule whose ends preferentially bond to the gold. You can think of it like this, the "solder" is a string that has glue on both ends. You first coat material one with the strings and assume that only one end of the string will stick, the other end of the string now floats up in the air. You then bring the other material close by and the free ends of the string now stick to it. You have essentially bonded (or soldered) the two materials together with the strings. This is what is happening with thiols on gold.
Now the thiols only like to conduct one way (like a diode). When they reverse the polarity, the thiols stop conducting. The wires are still soldered together, it's just that they no longer conduct current between them.
Jeremy