Tuesday, March 09, 2010

No, not that size...the other size

In the Giga-hyped world of nano-technology, one of the few materials making the grade are carbon-nano-tubes (CNTs for short). These are the tubular version of buckyballs (which never have amounted to even a nano-portion of their original hype). They are fabulous for boosting the mechanical properties of polymers, but this is all a topic for another day. My only point today regarding CNTs is about their size. They are very small, only a couple of nanometers in diameter. There pretty much at the limit between being a bulk material and being an individual molecule.

So imagine my surprise when I saw this headline:

“Nanocyl and 3B-Fibreglass Announce Joint Agreement for Developing CNT-Sized Glass Fibers.”

Wow! Glass fibers the size of a CNT! Keep in mind that CNT’s are built up in size from atoms, while glass fibers are built down in size from the everyday world (typically by pushing molten glass through a small circular opening and then pulling on it to make it even thinner in diameter.) Individual fiber optic glass strands are about 10 microns in diameter or so, a whole 3 orders of magnitude larger than CNTs. I couldn’t wait to find out about the technology breakthrough that would close that gap.

And then I realized that I had misunderstood the headline. "Size" refers not only to how large something is, it is also and old-but-still-used papermaking term for a coating applied to the web; the term is also used in other industries such as glass and fiber production. Such is the case here: the CNTs are applied as a sizing to standard glass fibers. Certainly interesting and potentially useful, but quite different from what I initially expected.

This is not the first time I’ve made that mistake. Many self-wound pressure-sensitive adhesive tapes (such as masking tape) have a sizing on them so that you can unwind the tape. This is often called a low-adhesion backsize. When I first started working at 3M, it took me quite some time for to realize that others were using the term “backsize” and not “backside”.

Here is the article if you wish to read it.

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