Nano Tubes
Written by: Tony Harris, February 25, 2016
One of the things I learned at university was how to research a subject. How to go into a library and find the information I needed, traversing the Dewey Decimal System as I went. If I got really stuck I’d dip into an encyclopedia, but this only as a last resort. In the world of Britannica or Americana, it is too easy to get lost. Something catches your eye and you wander down one path to another and suddenly it seems that you are a character in a Brothers Grimm story. Hours have passed, you don’t know how you got to where you are and the pubs are about to close! Which reminds me of the other thing I learned at university; alas, I digress.
We are working with a scientist at Rice University in Texas on an E&I 1040L RF amplifier. We asked him what his application was and he told us: Dielectrophoretic Assembly of Carbon Nanofiber Nanoelectromechanical Devices. “Oh” I thought – that’s nice.
I don’t use encyclopedias anymore; I Google®, I Yahoo®, I YouTube®. But they are no better. I set off on my journey to discover more about his application. I confidently typed in “Nano Tube” into the search box and clicked the little magnifying glass with Sherlock type inquisitiveness. I was immediately transported back to the late ‘70’s TV show with Mork saying ‘hello’ or in his language ‘nano nano’. Then to ‘Robin Williams and the history of golf’ – no don’t go there, get back on track. Apparently ‘nano’ is actually derived from the Greek word for dwarf. It is also Apple’s 3rd generation iPod after Classic and Mini. It is used as a prefix on a metric to denote one billionth – maybe I’m getting closer. What time is it? Blast I’ve missed lunch.
We all know that carbon is ubiquitous and found in so many forms. Diamond for example is one form or allotrope of carbon. It is the hardest naturally known substance, an excellent thermal conductor yet does not conduct electricity. Graphite is again just carbon, but here the atoms are arranged differently and so is a different allotrope. Graphite does conduct electricity; it is used in ‘lead’ pencils and as a lubricant. Carbon is found in all life forms – amazing stuff. But each of the different allotropes, as you can see, have differing mechanical, chemical and electrical properties.
One way you can arrange carbon atoms is to look a bit like a chicken wire fence, rolled up.
This allotrope of carbon is called a nano-tube. So we can see why ‘tube’ – why ‘nano’? The diameter of the tube is just a few nanometers. Or about 50,000 times thinner than a human hair. But not as thin as my hair! Just making sure you’re still with me.
Nanotubes have some very interesting properties. They exhibit extraordinary strength, they are very efficient conductors of heat and they conduct electricity.
It has been found that RF (radio frequency) fields can be used to manipulate nano tubes. Dielectrophoretic refers to a force being applied to a dielectric particle when subjected to an RF field. So Dr. Paul Cherukuri is using E&I’s RF amplifiers to produce this field as he seeks to grow nano-tubes.
By the way; if you have a few hours to kill before the pub opens – here is an interesting link for you: http://www.nanomagazine.co.uk/. Be careful though – you could still be there when it closes…