Researchers at the University of Illinois at Urbana-Champaign (UIUC) have created the world’s smallest chain-mail fabric. This fabric looks like the chain-mail armor worn by medieval knights, but can embed much more recent sensors to create some smart textiles. This fabric, which consists of "a network of small rings about 500 microns in diameter and even smaller links about 400 microns long," has unique electrical properties. For example, such a smart fabric could detect movement or damage, and even generate electricity to power the sensors embedded into it. But don't expect to wear a dress or a jacket made with it anytime soon.
This fabric has been made by Chang Liu, professor of electrical and computer engineering at UIUC, and graduate student Jonathan Engel. Liu is the director of the Micro Nano Technology Research Group (MNTR) and is very active in other areas. Last month, I wrote a post about his research project about fish-like sensors for underwater robots (February 22, 2007).
Now, let's look at a micrograph showing the underlying structure of this world's smallest chain-mail fabric, with its rings and links (Credit: Chang Liu, UIUC). Here is a link to a larger version.
And below is a picture of this microscopic chain mail fabric over a metal ball (Credit: Chang Liu, UIUC; and Institute of Physics). Here you can see a larger version.
Here are some more details about the rings and links of the fabric.
The fabric is similar in construction to the chain-mail armor worn by medieval knights. It consists of a network of small rings about 500 microns in diameter and even smaller links about 400 microns long (a micron is 1 millionth of a meter). The rings and links are built upon a planar substrate and then released to create a flexible sheet that can bend along two axes and drape over curved surfaces.
Because the rings and links can slide and rotate against each other, the fabric possesses unique mechanical and electrical properties. For example, the electrical resistance changes when the fabric is stretched. These properties could prove useful for the development of smart fabric and wearable electronic devices for pervasive computing.
Last month, New Scientist published an article about this new way to embed sensors into fabric. Here is an excerpt of Tom Simonite's story, "Microscopic chain-mail could link wearable gadgets" (February 20, 2007).
The fabric could be used to make smart clothing, says Liu. "We are interested in perhaps using it as a flexible textile or fabric that has properties like sensing or heating." It might also be possible to make the micro chain-mail using other materials, Liu says. "We are interested in making it out of polymers or a mixture of conductive and non-conductive materials," he says. "That research is currently being pursued." Microchip-scale electronic components could perhaps also one day be built directly into the links of the chain-mail, Liu says. The manufacturing technique employed should make this feasible. And this would allow sensors, communications or power components to be completely embedded within fully flexible fabrics.
For more information, this research work has been published by the Journal of Micromechanics and Microengineering under the name "Creation of a metallic micromachined chain mail fabric" (Volume 17, Number 3, March 2007, Pages 551-556). Here is a link to the abstract.
Sources: James E. Kloeppel, University of Illinois at Urbana-Champaign, via EurekAlert!, March 28, 2007; and various websites
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