Anti-fog glass is glare-free and self-cleaning

Posted by Emma Woollacott

MIT's created a new type of glass that's glare-free, self-cleaning and anti-fogging - useful for everything from car windscreens and scuba goggles to cellphones and solar panels.

When used in photovoltaic panels, says MIT, it could eliminate the loss of efficiency - up to 40 percent - caused by dust and dirt. And because it's non-reflective, it could gather substantially more energy, especially in the early morning and late afternoon.

The surface pattern of the glass consists of an array of nanoscale cones 100 nanometers tall and 200 across at the base. The surface is coated with several thin layers, including a photoresist layer, which is then illuminated with a grid pattern and etched away in stages to produce the conical shapes. The team has already applied for a patent on the process.

In future, they say, it could be even easier. Glass or transparent polymer films could be manufactured with the right surface features simply by passing them through a pair of textured rollers while still partially molten - a very cheap process.

Although the arrays of pointed nanocones on the surface appear fragile when viewed microscopically, the researchers say their calculations show they should be resistant to a wide range of forces, ranging from raindrops to poking with a finger.

"Multifunctional surfaces in animals and plants are common. For the first time, as far as I am aware, this paper learns a lesson in manufacturing efficiency from nature by making an optimized antireflective and anti-fogging device," says Andrew Parker, a senior visiting research fellow at Oxford University.

"This is the way that nature works, and may well be the future of a greener engineering where two structures, and two manufacturing processes, are replaced by one."