Boron nanotubes are very similar to carbon nanotubes, but actually have superior properties. Until recently it has been very difficult to synthesise this kind of nanomaterial of high purity, but researchers from Michigan Technological University (MTU) have come up with a way of making little Persian carpets of the tubes, using simple catalysts.
Boron Nitride is like Carbon
Boron nitride, chemical formula BN, forms large structure with equal amounts of boron and nitrogen. In the periodic table, boron and nitrogen are found either side of carbon, and the structure of boron nitride is electronically very similar to carbon, and it takes two structures, one very similar to graphite (hexagonal sheets) and one very similar to diamond (in fact it is almost as hard as diamond).
Boron Nitride Nanotubes have Superior Qualities
Equally, just as carbon can take the form of nanotubes – tubular molecules which can be a few nanometres in diameter and several microns in length – so can boron nitride. Boron nitride nanotubes (BNNT), however, actually have superior properties. They can withstand much higher temperatures – up to 1,100 degrees Celsius – temperatures at which carbon nanotubes would have burnt up. They are also perfect insulators which can be doped with other materials to form semiconductors which could be used in high powered electronics.
Extremely Hydrophobic
Another interesting property is that BNNT sheets shed water in a similar way to duck's feathers. This means that they are resistant to anything that is water soluble and could have many applications. The problem has always been that the synthesis of BNNTs has involved the use of an iron powder catalyst in an ammonia atmosphere, at temperature of almost 1,500 degrees Celsius, and even then the products are very impure.
Michigan Technological University Succeed in Synthesis
Now, however, a team from MTU, led by Associate Professor of Physics, Dr Yoke Khin Yap, has developed a way to grow BNNTs on a substrate made from simple catalysts: magnesium oxide, iron or nickel. The nanotubes can be made to grow exclusively on these catalysts, so that the exact location of their growth can be controlled.
Electronic Applications for Boron Nitride Nanotubes
There are potentially many applications for boron nitride nanotubes, especially in the field of electronics, because their electronic properties can be controlled much more precisely than they can in carbon nanotubes. The new method of synthesising them could open huge areas nanoscale electronics which have been impossible thus far. “I hope this encourages more researchers to grow BNNTs using the new technique,” said Dr Yap.
Source:
Harvesting the Divas of the Nanoworld, Newswise.
Simon Davies - Simon Davies has lived a varied life so far After completing a BSc in Chemistry at the University of Bristol, UK, he worked as a ...
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