Interlocking Carbon Nanotubes

**CrazedMathematician** · Mar8-05, 02:44 AM

(I'm not a material engineer so I apologize if any part of this post is idiotic.)
The main problem with carbon nanotubes is the difficulty with growing them long enough to be of any use. After doing some research, I found a site about carbon nanotube rings. So it got me thinking, why not, instead of trying to grow them long and interweaving them, form rings out of them and interlock the rings together. This would make sort of like a nanotube chainmail, with each nanotube ring being interlocked with many other rings. Here is the site about rings:

http://www.research.ibm.com/nanoscience/rings.html

And they also have this interesting pdf. If you look in Figure 1e you can see two interlocking nanotube rings, so interlocking them is possible.

http://www.research.ibm.com/nanoscie...rtel_Rings.pdf

If this could work, then they wouldn't need to be made nearly as long, and one would think you would still get much of the mechanical strength because you have to break the bonds between the carbon atoms (which is the strong part) to pull the rings apart. What do you guys think?

**russ_watters** · Mar8-05, 02:11 PM

Nanotube chain mail (think: kevlar vests) is a fine idea, but I think you may miss the point: it isn't the individual strand length that's the problem, its the overall manufacturing capacity. Whether its 1000 1mm strands or 1 1m strand, its still 1m of nanotubes (numbers pulled out of the air) and we are currently unable to produce that much of the stuff.

**brewnog** · Mar8-05, 02:22 PM

You might be interested in some related research ongoing at the University of Manchester; they've created a two-dimensional fabric.

http://www.azonano.com/news_old.asp?newsID=382

**PerennialII** · Mar8-05, 04:12 PM

Very interesting links ... thanks ! Given time (hopefully not much, actually considering the effort might not be that far away) nanotube chain mail, fabrics and all related constructs can start producing some "real life" applications where their potential can truly be exploited. And the computational work related to nanotubes is definitely one of the most interesting research topics today.

**CrazedMathematician** · Mar9-05, 03:30 AM

Originally Posted by russ_watters

Nanotube chain mail (think: kevlar vests) is a fine idea, but I think you may miss the point: it isn't the individual strand length that's the problem, its the overall manufacturing capacity. Whether its 1000 1mm strands or 1 1m strand, its still 1m of nanotubes (numbers pulled out of the air) and we are currently unable to produce that much of the stuff.

See I don't think thats it. It's easy to grow tons of short ones but longer ones are much harder. Here's an article about scientists growing a nanotube to a "world record length of 4 cm":

http://www.lanl.gov/news/releases/archive/04-076.shtml

And here's a company in China that mass produces nanotubes for a mere $1.5 to $3 a gram (depending on purity and quantity), way lower than just a few years ago:

http://www.sunnano.com/

Nanotubes naturally grow very small, so if you want to make them big enough to make fibers out of them it takes a lot more work. Back to the interlocking ring concept, I think it could work if you made some sort of system where the rings that didn't interlock with other rings are disgarded. Who knows if someone will make it work or not...

**noobie** · Mar9-05, 04:00 AM

Not sure if I completely understand the chainmail idea but from what I know of carbon nanotubes, it's the mechanical (and quatum) properties that make it intriguing. Single walled carbon nanotubes have already hit the commercial market for the avg consumer in golf shafts. And my guess is that you wouldn't necessarily want to grow super long nanotubes if you want to take advantage of its mechanical properties. The longer something is the easier it is to deform. Carbon nanotubes are touted for their strenght and stiffness all the while being ultralite. My guess is you would lose a lot of the mechanical strength by going to a chainmail configuration.

**CrazedMathematician** · Mar9-05, 08:38 PM

Originally Posted by noobie

Not sure if I completely understand the chainmail idea but from what I know of carbon nanotubes, it's the mechanical (and quatum) properties that make it intriguing.

The nanotubes are all formed into rings and each ring interlocks with surrounding rings, forming a sort of molecular chainmail.

Single walled carbon nanotubes have already hit the commercial market for the avg consumer in golf shafts. And my guess is that you wouldn't necessarily want to grow super long nanotubes if you want to take advantage of its mechanical properties. The longer something is the easier it is to deform.

Well you have to make the nanotubes long enough to weave into a pattern. You can't weave nanotubes that are only a few nano/micrometers long because you would need something to hold them together which would make the strength of the material significantly less than a SWNT.

Carbon nanotubes are touted for their strenght and stiffness all the while being ultralite. My guess is you would lose a lot of the mechanical strength by going to a chainmail configuration.

No materials so far has even come close to the strength of a single nanotube, because, like I said above, you have to hold them together with something. So your choices are either some kind of an epoxy (which severely limits the strength), trying to bond the individual nanotubes together (which also limits the strength because they are only held together by weak Van Der Waal forces), or growing of them of sufficient length so they span the entire length of the material (which is much stronger because it requires breaking the individual nanotubes, the strong part). The chainmail idea is another alternative, which, like the last one, requires breaking the sp2 bonds between carbon atoms in the nanotubes for the material to yield. Now if someone working on nanotubes could just tell us if this is feasible...

**noobie** · Mar9-05, 11:14 PM

I just a did a little reading and it looks like someone has done something similar (crosslinking the nanotubes via irradiation to increase the mechanical strength of bulk nanotubes).

http://www.nature.com/cgi-taf/DynaPa.../nmat1078.html

**el_hijoeputa** · Mar12-05, 08:42 PM

Some briefs, from a recent email (MRS News):

New life for nanotubes
(Nature Materials Update)
Resesarchers have discovered a method for restarting the growth of open-ended carbon nanotubes in a way that preserves the atomic-scale structure of the original tubes. The 'fresh growth' of the tube, catalysed by a metal nanoparticle sitting at the tube's open tip, preserves both the diameter and the helical pitch of the rows of hexagonal carbon-atom rings of these features of the initial tube.
(3.4.05)

Nylon-Nanotube Fibers
(Science - Editor's Choice)
Caprolactam was used as both solvent and monomer for incorporating single-walled nanotubes (SWNTs) into a nylon-6 matrix. The tensile strength and Young's modulus of nylon-6 improved by about a factor of 2 to 3 for SWNT loadings of 0.5 to 1.5 weight %.
[J. Am. Chem. Soc. 10.1021/ja446193 (2005)]
(3.11.05)

**russ_watters** · Mar12-05, 10:35 PM

Originally Posted by CrazedMathematician

See I don't think thats it. It's easy to grow tons of short ones but longer ones are much harder.

I guess I really don't know. Thing is though, if you could join the ends of one strand to make a ring, you could also join the ends of two strands to make a longer one. Either way, if they really can make them in quantity, that's a pretty big deal. My carbon nanotube composite shaft driver will be light as a feather.

**willib** · Mar14-05, 08:55 PM

CrazedMathematician , i looked at the first url you provided and i was surprised that the nano rings werent as symetrical as i would have thought..

~~RGClark~~ · Apr19-05, 12:41 PM

Originally Posted by CrazedMathematician

(I'm not a material engineer so I apologize if any part of this post is idiotic.)
The main problem with carbon nanotubes is the difficulty with growing them long enough to be of any use. After doing some research, I found a site about carbon nanotube rings. So it got me thinking, why not, instead of trying to grow them long and interweaving them, form rings out of them and interlock the rings together. This would make sort of like a nanotube chainmail, with each nanotube ring being interlocked with many other rings. Here is the site about rings:

http://www.research.ibm.com/nanoscience/rings.html

And they also have this interesting pdf. If you look in Figure 1e you can see two interlocking nanotube rings, so interlocking them is possible.

http://www.research.ibm.com/nanoscie...rtel_Rings.pdf

If this could work, then they wouldn't need to be made nearly as long, and one would think you would still get much of the mechanical strength because you have to break the bonds between the carbon atoms (which is the strong part) to pull the rings apart. What do you guys think?

I saw an instance of a material claimed to have truely outrageous strength properties because of interlocking rings that I wonder if anyone had heard of:

Hanging Tough.
"Perfect diamond is a another real material, but there is a theoretical
material which is far stronger. It, too, uses carbon, but in the form
of benzine-like rings. These are looped through each other in a
three-dimensional matrix, and the impressive figures (1.0 X 10^15
(that's a 1 followed by 15 zeroes), 9.3 X 10^14, and 9.3 X 10^12
N/cm^2) for the yield strengths come from the fact that not only is
deformation resisted by the normal molecular bonds, but by the mutual
repulsion of the shared electron clouds around the rings. As you can
imagine, this also makes the material extremely rigid. And hard. (My
thanks to Dr. John Brantley for telling me about this.)"
http://www.dcr.net/~stickmak/JOHT/joht10strength.htm

*He's giving these in strength numbers in N/cm^2 remember; so in pascals you would multiply these by 10,000. Then this material is claimed to have a strength in tension and compression of 10 billion gigapascals! The largest quoted strength I've seen for carbon nanotubes is 160 gigapascals.
*I wonder if he made a mistake and the numbers he was given for this
material were actually already in pascals, N/m^2. Even then that would
mean a strength of 1 million gigapascals.
*To put this is in perspective such a material could be used to build
both a space elevator and space tower to geosynchronous orbit WITH NO
TAPER. (Actually they might even be enough to strech to Mars!)

* *Bob Clark