RMIT University has developed a self-modifying coating 1000 times thinner than a human hair that automatically lets in heat when it’s cold and blocks heat when it’s hot. The researchers behind the breakthrough say it could lead to the creation of self-regulating smart windows and “temperature-responsive buildings”.
The coating is created with vanadium dioxide, which at 67°C transforms from an insulator to a metal, staying transparent but becoming opaque to infrared radiation.
The RMIT researchers developed a way to create and deposit the coating directly to materials like glass without the need for the creation of specialised layers, or platforms, as had previously been needed
Lead investigator Associate Professor Madhu Bhaskaran said the breakthrough could help the built environment sector become more sustainable.
“We lose most of our energy in buildings through windows,” Dr Bhaskaran said.
“This makes maintaining buildings at a certain temperature a very wasteful and unavoidable process. Our technology will potentially cut the rising costs of airconditioning and heating, as well as dramatically reduce the carbon footprint of buildings of all sizes.”
The researchers said smart windows were 70 per cent more efficient than dual-pane glass in summer and 45 per cent more efficient in winter, though current technology generally requires electrical input to change the glass’s infrared opacity.
“Our coating doesn’t require energy and responds directly to changes in temperature.”
Co-researcher and PhD student Mohammad Taha said the coating’s automatic switching ability could also be overridden by a simple switch.
“This switch is similar to a dimmer and can be used to control the level of transparency on the window and therefore the intensity of lighting in a room,” Mr Taha said.
“This means users have total freedom to operate the smart windows on demand.”
The technology could also find applications in medical and security imaging, and controlling radiation that can penetrate plastics and fabrics.
The research team has filed to patent the technology in Australia and the US, and is looking to roll out the technology as soon as possible.