.A new material has been developed starting with the smallest of building blocks, called nanostructures. It involves a sort of varnish which, when applied, creates a strong but see-through coating that can report on its environment by changing color from blue to fluorescent red, depending on conditions.
The idea was inspired by the known strength of seashells, said researcher Jeff Brinker, a scientist at Sandia National Laboratories and the University of New Mexico, where the material was developed. He explains that the material's layered effect is similar to a common shell, though it is a synthetic product.
with temperatures that plunge to minus 170 degrees Fahrenheit (minus 112 degrees Celsius).To make an inflatable Martian house, a varnish of nanostructures would be layered over more conventional material, Brinker explained in a telephone interview, resulting in a see-through covering that would change color when outside temperatures rose to dangerous levels. It would be sensitive to leaks in the roof and exposure to certain chemicals.
The new technique is discussed in the April 19 issue of the journal Nature.
No firm plans are in place at NASA to use the material. However, it could show up soon in computers, printers and other household devices that require tiny internal sensors and switches, Brinker said. It could also provide a cheaper alternative to common devices like thermometers, or equipment that analyzes material stress or sniffs out chemicals.
Nanostructures of various kinds have been developed and studied for similar purposes. The relatively new field has shown tremendous promise, but the cost of assembling tiny structures has limited the field's impact so far.
Better than spaghetti
The newly developed material is made by linking simple lightweight molecules called monomers into heavier, more complex molecules called polymers.
Previous attempts to do this have resulted in "a huge bowl of entangled spaghetti," said Brinker. "Our method organizes this jumble by forcing them to adopt a particular conformation; that is, we organize them into nanostructures. We can force them into conformations, and so define where the polymer is and isnt. Then we can control how interactions between polymer units will affect a materials electrical and optical properties."
The underlying "conjugated polymers" dealt with in the study date back to 1977, and the researchers that first developed them -- Alan J. Heeger, Alan G. MacDiarmid and Hideki Shirakawa -- just this year received a Nobel Prize for their work.
The new method was described by Brinker as "a simple means of forcing organization that should help us integrate conjugated polymers into devices." Early, simple versions of the method were developed in 1997.
The process produces "a seashell-like layering at once very strong and non-brittle, nanoscopic spheres that can hold catalysts or medicine, intelligent ink that assembles during ink-jet printing and self-assembled nanostructures with pore sizes alterable by light to a fineness of 0.2 angstroms," the researchers said.
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