If you're a Star Trek fan, you may remember Scotty
giving the formula for "transparent aluminum" to a 20th century Earth man in
"The Voyage Home". Well researchers at Penn State University have cracked
one of the mysteries on the way to transparent metals. The researchers set out to
accomplish a task never before completed...make uniform pores in the size range between 10
and 100 nanometers. In the past, researchers have been able to create pores larger
than 100 nanometers using polymer spheres as templates. They could also produce
pores less than 10 nanometers by using molecules as templates, but the 10-100 nanometers
range alluded them as no suitable template was available.
The Penn State researchers had come across an article printed in 1990
describing a method of producing identical silica spheres of only 35 nanometers in
diameter. The researchers wanted to try using this "high tech" sand as a
template for new materials. By adding an organic monomer to a pellet of the pressed
sand and then processing the monomer to a polymer, the researchers were able to chemically
dissolve the silica spheres. The result is 75% empty space surrounded by polymers.
Potential uses for these porous materials are nearly unlimited.
They could be used to separate chiral compounds in the pharmaceutical industry.
Also, since the length scales of the pores are well below the wavelength of light, any
material made with the pores will be transparent....even metals!
