There's a scene in Bladerunner, Ridley Scott's sci-fi classic,
when Harrison Ford's character, Deckard, is about to interview
Rachael, played by Sean Young, to test whether she's a real
human-or a replicant. ["It's too bright in here."] On cue, the
floor-to-ceiling windows dim, shading the room from the golden
sunlight outside.
It was a beautiful Hollywood effect when the movie came out in
1982. And now it may not be that far from reality. Because
researchers at Harvard recently designed a material that, with
a shot of electricity, can transform a glass window from transparent
to opaque in less than a second.
The team built the window by sandwiching glass between two sheets
of a transparent, balloon-like rubber material, laced with silver
nanowires. As is, the material is clear. But apply voltage, and
the nanowires are attracted to each other ever so slightly across
the glass-which deforms those rubbery sheets just enough to scatter
light, causing the glass to cloud up. They describe the device in
the journal Optics Letters. [Samuel Shian and David R. Clarke,
Electrically tunable window device]
Study author Samuel Shian, a materials scientist, says this smart
glass is cheaper than others, and uses minimal power-much less,
for example, than something like a curling iron. And, since it's
flexible and foldable, he says it could even be used for things
like camouflage uniforms, to switch, for example, from green and
brown to white and gray. "This would be very useful when the
background landscape suddenly changes, such as during early snowfall."