Windows that can change their opacity have been around for a while (see this discussion from a prior article), but the methods are too expensive to outfit entire skyscrapers. Until now.
(Smart windows - not curtains?)
"They are all very effective, although I think ours is even more effective. But the big problem is how you create large areas, windows, and the cost," said Professor David Clarke, a material scientist at Harvard.
The scientists have figured out a method to produce windows that go from clear to cloudy at the flip of a switch in a way that is both cost effective and commercially viable, according to a study they published in the journal Optical Letters.
The team uses elastomer rubber coated with nanowires that adheres to glass to scatter light when voltage is applied.
"When you apply a voltage to them relative to some background there is an attractive force between the nanowires and the substrate that deforms the elastomer," said Clarke. "Elastomer rubber is very soft and so the surface becomes rough, and it is that roughness that scatters light," Clarke added.
Samuel Shian, an author on the study, believes scaling this technology should be commercially viable because the reaction is physical rather than chemical. Current chemical-based controllable windows use vacuum deposition to coat the glass, an expensive process that deposits layers of a material molecule by molecule.
In his 1972 novel The Godmakers, Frank Herbert wrote about special windows that could be clear or opaque with the touch of a button:
Orne returned to his room to change for dinner, stopped at the polawindow, which he tuned to clear transmission. The quick darkness of these latitudes had pulled an ebony blanket over the landscape. Distant cityglow painted a short yellow horizon off to the left. An orange halo remained on the peaks where Marak's three moons would rise.
(Read more about Frank Herbert's polawindows)