If you prefer natural lighting to electric indoor lights, imagine how great it would be if you could have transparent walls and roof beams. Sunlight could pour into your living room from every angle. That might sound crazily futuristic, but it may soon be reality. That's because Swedish researchers have developed a type of composite wood that is virtually transparent.
In a study just published in the American Chemical Society journal Bio Macromolecules, scientists from Sweden's KTH Royal Institute of Technology describe their creation of a "nanoporous cellulosic template." That's essentially a fancy term for wood that's been altered structurally, so that it allows as much as 85 percent of light to pass through it. That's actually close to the light-transmittance level of clear glass, which allows between 80 and 99 percent of light through.
How did they pull off that trick? The researchers heated wood and treated it with chemicals to remove lignin, an organic substance — sort of a natural plastic — that binds together the ingredients of wood, and in the process gives wood its color. To allow light to go through even more easily, they replaced the lignin in the walls of wood cells with methyl methacrylate, a substance that you probably know by the brand name Plexiglas.
"When the lignin is removed, the wood becomes beautifully white," Lars Berglund, a professor at KTH's Wallenberg Wood Science Center, explained in a press release. "But because wood is not naturally transparent, we achieve that effect with some nanoscale tailoring."
So far, the see-through wood has only been produced in tiny quantities, but the process would be scalable to produce building materials, the scientists say.
Because the material isn't totally transparent, it would be possible to create walls, roofs and even windows that would let in plenty of light but still allow residents of buildings to have some degree of privacy, according to Berglund. In the process, they could save on their electricity bills, since having all that natural light would free them from having to rely so much upon lamps and light fixtures.
Berglund also envisions using the translucent wood to create big arrays of solar cells on the exteriors of houses and buildings.
The transparent wood is just the latest in an array of see-through materials developed in recent years by researchers. Hungarian architect Aron Losonczi has developed a hybrid light-transmitting concrete with glass fibers mixed into the material. And in 2015, researchers at Pennsylvania State University created a new type of transparent metal that could be used to make large-screen TVs, computer monitors and "smart windows."
In March, Japanese architect Kazuyo Sejima unveiled a design for a commuter train with some parts that are transparent and others that reflect light. The idea is that the train would blend into its surroundings almost invisibly. European aircraft manufacturer Airbus also has envisioned a future airliner with a fuselage that could become transparent, giving passengers a 360-degree view of the sky and eliminating the need for windows.