Scientists use nanomaterials to grow 'flying carpets' and 'nano kites'

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Washington, July 30 (ANI): Scientists at Rice University are using nanomaterials to grow 'flying carpets' and 'nano kites'.

Led by Rice University chemist Bob Hauge, the team describes a method for making "odako," bundles of single-walled carbon nanotubes (SWNT) named for the traditional Japanese kites they resemble.

It may lead to a way to produce meter-long strands of nanotubes, which by themselves are no wider than a piece of DNA.

Hauge, and his co-authors, graduate students Cary Pint and Noe Alvarez, explained that the odako, after which the bundles are named, are gigantic kites that take many hands to fly, hence the many lines that trail from them.

In this case, the lines are nanotubes, hollow cylinders of pure carbon.

Individually, they're thousands of times smaller than a living cell, but Hauge's new method creates bundles of SWNTs that are sometimes measured in centimeters, and he said the process could eventually yield tubes of unlimited length.

Large-scale production of nanotube threads and cables could be used in lightweight, superefficient power-transmission lines for next-generation electrical grids, for example, and in ultra-strong and lightning-resistant versions of carbon-fiber materials found in airplanes.

Hauge said that the SWNT bundles may also prove useful in batteries, fuel cells and microelectronics.

Last year, Hauge and colleagues found they could make compact bundles of nanotubes starting with the same machinery the US Treasury uses to embed paper money with unique markings that make the currency difficult to counterfeit.

Hauge and his team used this printing process to create thin layers of iron and aluminum oxide on a Mylar roll.

They then removed the layers and ground them into small flakes.

In a mesh cage placed into a furnace, the metallic flakes would lift off and "fly" in a flowing chemical vapor.

As they flew, arrays of nanotubes grew vertically from the iron particles in tight, forest-like formations.

When done cooking and viewed under a microscope, the bundles looked remarkably like the pile of a carpet.hile other methods used to grow SWNTs had yielded a paltry 0.5 percent ratio of nanotubes to substrate materials, Hauge's technique brought the yield up to an incredible 400 percent.

The process could facilitate large-scale SWNT growth.

In the latest research, the team replaced the Mylar with pure carbon.

In this setup, the growing nanotubes literally raise the roof, lifting up the iron and aluminum oxide from which they're sprouting while the other ends stay firmly attached to the carbon.

As the bundle of tubes grows higher, the catalyst becomes like a kite, flying in the hydrogen and acetylene breeze that flows through the production chamber. (ANI)

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