nanoparticle discovery could hail revolution in nanotube manufacturing

NANOSPHERES(Nanowerk News) A nanoparticle shaped like a spiky  ball, with magnetic properties, has been uncovered in a new method of  synthesising carbon nanotubes by physicists at Queen Mary University of London  and the University of Kent (“Boundary layer chemical vapor synthesis of  self-organized radial filled-carbon-nanotube structures”).

Sea Urchin nanoparticle

Sea Urchin Nanoparticle

Carbon nanotubes are  hollow, cylindrical molecules that can be manipulated to give them useful  properties. The nanoparticles were discovered accidentally on the rough surfaces  of a reactor designed to grow carbon nanotubes.

Described  as sea urchins because of their characteristic spiny appearance, the particles  consist of nanotubes filled with iron, with equal lengths pointing outwards in  all directions from a central particle.

The  presence of iron and the unusual nanoparticle shape could have potential for a  number of applications, such as batteries that can be charged from waste heat,  mixing with polymers to make permanent magnets, or as particles for cancer  therapies that use heat to kill cancerous cells.

The researchers  found that the rough surfaces of the reactor were covered in a thick powder of  the new nanoparticles and that intentional roughening of the surfaces produced  large quantities of the sea urchin nanoparticles.

“The surprising conclusion is that the sea urchin nanoparticles  grow in vapour by a mechanism that’s similar to snowflake formation. Just as  moist air flowing over a mountain range produces turbulence which results in a  snowfall, the rough surface disrupts a flow to produce a symmetrical and ordered  nanoparticle out of chaotic conditions,” said Dr Mark Baxendale from Queen  Mary’s School of Physics and Astronomy.
On analysis, the researchers found that a small fraction of the  iron inside the carbon nanotubes was a particular type usually only found in  high temperature and pressure conditions.
Dr Baxendale added: “We were surprised to see this rare kind of  iron inside the nanotubes. While we don’t know much about its behaviour, we can  see that the presence of this small fraction of iron greatly influences the  magnetic properties of the nanoparticle.”
Source: Queen Mary University of London

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