Wood sheds its reputation for being traditional or old-fashioned as scientists introduce "transparent wood," which is setting a new standard for energy-efficient materials.
Presenting the new material at the American Chemical Society Spring 2019 National Meeting & Exposition, the team of scientists unveiled the innovative type of wood that could pave the way to unparalleled energy efficiency in design and architecture.
Transparent Wood: A New Energy-Saving Material
Transparent wood absorbs and releases heat, which makes it an incredible energy saver. Like glass, its transparent properties mean that it can also transmit light to keep homes bright and heated.
Three years ago, a team led by Lars Berglund, Ph.D., specially treated wood to make it transparent with better thermal insulation than glass.
"In this work, we tried to reduce the building energy consumption even more by incorporating a material that can absorb, store and release heat," Céline Montanari explains in a press release from ACS.
To accomplish this, the scientists added polyethylene glycol (PEG) to the wood that is already transparent due to the removal of light-absorbing component lignin from its cell walls.
According to Montanari, PEG was chosen not just because it can store heat, but also because it has a high affinity for wood. It is a polymer that's dubbed as "phase-change material," since PEG is a solid that melts at a certain temperature.
"During a sunny day, the material will absorb heat before it reaches the indoor space, and the indoors will be cooler than outside," she adds. "And at night, the reverse occurs — the PEG becomes solid and releases heat indoors so that you can maintain a constant temperature in the house."
Acrylic has also been incorporated into the material to help it withstand humidity more. The result: a transparent wood that is extremely strong and capable of carrying heavy loads with the extra perk of being able to store heat.
An Eco-Friendly Material For Architecture?
Aside from being even more energy-efficient than glass, the scientists' transparent wood is also an extremely eco-friendly material.
Wood and PEG, after all, are both biodegradable materials that can be disposed of easily once it is no longer needed. Acrylic isn't biodegradable, but Berglund points out that this material could simply be replaced by a different polymer.
However, not everyone is convinced that biodegradable materials are the way to go. Mark Miodownik of the University College London, who wasn't involved in the research, says that biodegradable materials aren't necessarily more environmentally sustainable.
"We need construction materials to be carbon sinks and so they need to be recyclable and reusable, not biodegradable," Miodownik explains to The Guardian.
He adds that a good option would be to recover, reuse, and repurpose this new type of wood.
Montanari, Berglund, and the rest of the team are currently tweaking the production process to make transparent wood available for industrial purposes. In about five years, researchers estimate interior designers and architects could already use this material for niche applications.