Variable transmittance window has always been part of smart home scheme. Imaging at a press of a button, the windows will go completely “dark” or create climate adaptive transmittance based on outdoor brightness and temperature to save costs for HVAC. However, most variable transmittance windows require power, working in a way similar to B/W LCD screen. In addition to the cost of the windows, the need for continuous power supply is also troublesome in a way.

Recently, in a research conducted by MIT on a rubbery polymer known as polydimethylsiloxane (PDMS), scientists discovered how to predict one of its special properties – in its normal formation, PDMS contains some opaque darkened regions. When the polymer gets stretched or deformed mechanically, these regions will become more transparent. After experiments with dye particles and different degrees of deformation, scientists at MIT developed an equation to predict the light transmittance through PDMS. By using this equation, glass manufacturers will be able to determine how much of polymer they need to apply between glass layers or on the surface of the windows to achieve the desired results. While the material changes its transparency by deformation, the product does not rely on electricity to be “smart” and makes installation much easier.