The new polymer made of PDMS that could be used in new smart windows. MIT scientists have created a new polymer called polydimethylsiloxane (PDMS), which could be the basis for new smart windows. The polymer works by stretching to become more transparent and allow more light through. (via MIT)
MIT researchers have found out how to accurately predict the amount of light coming through a stretched piece of polymer called polydimethylsiloxane (PDMS). This simple new equation was just a fun accident that has led them to look for new applications – primarily in smart windows. The PDMS is opaque, but becomes more transparent as it’s stretched, like a pair of ladies’ tights.
At first, the MIT researchers were just stretching a piece of PDMS and predicting how much light would come through as a game (because this is obviously the sort of thing MIT researchers do in their spare time). When they found they could accurately predict the amount of light allowed through the PDMS at varying levels of stretching (also known as ‘mechanical deformity’), they decided to make an actual experiment out of it.
Their first experiments used dye particles within the PDMS and first measured how much light came through without mechanical deformity – simply based upon the polymer’s thickness. Then, they stretched it in front of a light source to measure the light coming through. When their predictions were starting to compare with their actual data, they got a little more serious and exact. Their current experiment, which you can see here:
It places the PDMS polymer on a lightbox with the MIT logo. Instead of simply stretching the material by hand, they use syringes filled with air to control how much the polymer is stretched. As the polymer stretches and becomes more transparent, the MIT logo can be seen and the amount of light from the lightbox can be measured. These experiments allowed them to create an accurate equation, based upon Beer-Lambert’s Law of how light passes through materials. Their equation uses the material’s properties, thickness, and degree of mechanical deformity (stretching), to accurately predict exactly how much light comes through. They think this can be used to create smart windows that can let in appropriate amounts of light by stretching. They also think this could lower energy and cooling bills by enabling you to allow the right amount of sunlight in your home: allowing Mother Nature to heat your home.
Typical ‘smart windows’ have grids of nanocrystals within a conductive material that is then placed within a glass-like material. When the material becomes electrically charged, it changes the way the glass looks: i.e. more or less opaque as it allows or disallows the sun’s rays. A recent window created by Delia Milliron, a chemical engineering professor at the University of Texas, has recently created a smart window that can block visible light and near-infrared light to act as sunglasses for your windows; this design can be very useful for aircraft.
The polymer idea is far less complicated and made with cheaper materials, hence why the research team thinks they have a viable idea for the next generation of smart windows that businesses and consumers alike may actually buy. The team thinks that their smart windows idea will work more like shades that can be stretched specific amounts to allow the right amount of light, based upon their equation.
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