A sheet of the “beautifully white” modified balsawood (KTH)

Swedish team produces transparent wood for windows and facades

4 April 2016 | By GCR Staff 4 Comments

We may soon be able to see the forest despite the trees after researchers at Sweden’s KTH Royal Institute of Technology announced the creation of a transparent wood that can be mass produced to replace glass in windows, façades and solar cells.

Their experiment involved removing lignin from a piece of balsa wood and infusing it with a transparent plastic polymer.

“Transparent wood is a good material for solar cells, since it’s low-cost, readily available and renewable. This becomes particularly important in covering large surfaces with solar cells”– Lars Berglund, KTH professor

Lars Berglund, a professor at Wallenberg Wood Science Centre at KTH, said that although “optically transparent” wood had been produced in microscopic samples, the KTH project introduced a way to use the material on a greater scale, and for large structures.

“Transparent wood is a good material for solar cells, since it’s low-cost, readily available and renewable,” Berglund said. “This becomes particularly important in covering large surfaces with solar cells.”

“No one has previously considered the possibility of creating larger transparent structures for use as solar cells and in buildings,” he added.

Berglund said panels of transparent or translucent wood could also be used for windows and façades where some privacy was required.

The clear wood is formed by removing lignin, one of its basic chemical components. “When the lignin is removed, the wood becomes beautifully white,” Berglund said. “But because wood is not naturally transparent, we achieve that effect with some nanoscale tailoring,” he says.

In the experiment, the lignin of a sample of balsa wood was replaced with a transparent plastic polymer and the optical properties of the two were matched. The resulting material was twice as strong as Plexiglass.

Among the work to be done next is enhancing the transparency of the material and scaling up the manufacturing process, as well as experimenting with other types of wood.

The finding was published in the American Chemical Society journal, Biomacromolecules.

Photograph: A sheet of the “beautifully white” modified balsawood (KTH)