Transparent wood could one day replace the glass windows. A process to make it transparent also gives it heat retention powers, which could help regulate the temperature of buildings.
Celine Montanari of the Wallenberg Wood Science Center in Sweden and her colleagues have drawn on previous work to create transparent wood by removing a structural component called lignin from wood, allowing light to filter out.
For the next step, the team imbibed de-lignified birch wood in PEG (polyethylene glycol), a polymer also used in theater smoke machines and toothpaste. When wood panels are encapsulated, it’s harder to get through the heat – whether you’re insulating a building from the cold outside or trying to keep the summer heat.
PEG is solid at room temperature, but melts at 30 ° C, although it remains stuck in the wood structure.
“When we build, we try to use a lot of glass, but it has the disadvantage of being a bad insulator, resulting in large heat losses,” says Montanari. “The wood is really amazing, it insulates 10 times better, but it does not transmit light.”
Composite wood is not as good as natural wood, but it is about four times better than high-end double glazing.
The material can also withstand heavy loads and is biodegradable, making it easier to remove than concrete or glass.
Modified wood is still not perfectly clear – when the PEG is solid, the material has a white veil similar to frosted glass. But Montanari is confident that these first challenges can be overcome by fine-tuning the chemistry or using different wood species.
The work was presented at a meeting of the American Chemical Society.