Affordable Smart Windows Are On Their Way

A group of scientists from MIT have supposedly made one application by conjuring up an equation that can predict how light goes through a rubber-like polymer structure — having the power to tweak your windows’ opacity depending on the weather.

The rubbery material they used called polydimethylsiloxane has dark regions when at rest but gets more and more transparent as you stretch it. One of the researchers, Francisco López Jiménez, says the decision to undertake the project was a happy accident. By mixing in micron-sized dye particles, they prepared some small pieces of material for their experiments.

Jiménez said, ‘We were just playing with the material, and we soon got interested in how we can predict this and get the numbers right.
Manufacturers can make smart windows much more affordable than see-through screens being developed by some companies today. That’s possible by putting layers of the polymer on top of each other. Any manufacturer can find out how much pressure to apply on windows to turn them transparent by using the group’s equation.

MIT describes the groups’ process — they compared their measurements with predictions from their equation, which they devised using the Beer-Lambert Law, a classical optics theory that describes the way light travels through a material with given properties. The team combined this theory with their experimental analysis, and derived a simple equation to predict the amount of light transmitted through a mechanically deformed PDMS structure.

Smart windows can ultimately lower heating and air conditioning bills since a house’s or building’s residents can control how much sunlight to let in.