Wood is a strong, versatile building material but it rots, gets eaten by termites and blocks light. Now engineers have figured out how to turn it transparent and even stronger.
During a 2 h chemical treatment, the lignin is spatially removed in natural wood to make it transparent while preserving its natural patterns. Aesthetic transparent wood has outstanding optical, mechanical and multifunctional properties.
1. Light Transmission
Researchers at the University of Maryland have turned ordinary sheets of wood into transparent material that’s nearly as clear as glass and could save on energy costs in buildings. They’ve done it by chemically removing lignin from the veneer and impregnating it with a transparent polymer known as polymethyl methacrylate, or Plexiglas.
The refractive index contrast between the wood and the infiltrating polymer can be controlled by varying the delignification conditions and the size of pores in the cellulose template. The resulting transparent composites based on balsa, poplar and beech have high optical transmittance with haze below 1%.
Besides being transparent, the material also has mechanical properties similar to those of glass. The tensile strength and modulus of transparent wood are higher in the longitudinal direction, due to the anisotropic nature of the cell wall structure. The team is now working to make the process more efficient and to engineer the material for specific applications, such as insulating skylights or even batteries. They’re also experimenting with ways to make it biodegradable and scale up production.
2. Thermal Insulation
Scientists have made a big leap toward transparent wood as a building material that could reduce energy consumption. They have found a way to transform regular wood into a transparent material that can also store and release heat. This would help reduce energy costs in homes and buildings by replacing some of the glass that is typically used.
The scientists made their transparent wood by chemically removing the lignin that makes it opaque and adding polymer to make it stronger. The resulting wood is 85% transparent and can be hardened with epoxy resin. The team is now working to improve its transparency and scale up production.
The researchers are also working to create a more environmentally friendly process for making their transparent wood. It is not currently possible to produce large amounts of the material, because it requires a lot of chemistry and high temperatures that are not very sustainable. However, they are developing a method that uses less toxic chemicals and can be done in a backyard. This will increase the potential for this technology to become a reality in the near future.
3. Fire Resistance
Researcher Lars Berglund and his team have developed a way to eliminate colour, some chemicals and add polymers to wood in order to make it transparent. Their discovery could have many applications, from windows and skylights to electrical insulation and electromagnetic interference (EMI) shielding.
The material has all the strength of opaque wood and can withstand much stronger impacts than glass, bending or splintering rather than shattering. It also transmits light more efficiently and eliminates glare. It can also absorb and release energy to help keep a building at a steady temperature and cut energy costs.
In addition, the new material can bear heavy loads and is biodegradable, making it a potential candidate for eco-friendly homes. Montanari and her colleagues are working to increase its heat storage capacity and ramp up production in order to get it onto the market as soon as possible. They say it could be ready for commercial use within five years. Wood may seem more at home in log cabins than modern architecture, but a specially treated type of timber could be the latest trend in eco-friendly construction. Scientists have developed transparent wood that not only transmits light, but also stores and releases energy – helping to cut energy costs and reduce carbon emissions.
4. Privacy
Researchers discovered that by removing lignin, the substance that gives wood its strength and rigidity, they could make transparent wood. The resulting material is impregnated with a polymer known as polymethyl methacrylate, or Plexiglas. The team says that the new composite is up to 85% transparent, and is a step closer to real transparent wood.
The aesthetic wood demonstrates integrated advantageous features including high optical transmittance, tunable haze and light guiding, which are important for energy efficient building applications like pattern ceilings1.
This translucent wood is able to reduce glare while allowing the passage of sunlight. It also has low thermal conductivity compared to glass, making it an ideal building material.
Montanari’s team has already started working on other potential applications for their transparent wood, such as increasing the material’s heat storage capacity and developing a process to scale up production. She hopes that it will eventually replace some of the glass used in buildings, and reduce energy consumption.
5. Strength
Unlike glass, which can shatter when hit, transparent wood bends or splinters instead. It can also withstand much greater stress and strain than normal wood, making it suitable for load-bearing walls. It’s also a green material, sourced from a renewable resource and made using existing industrial processing equipment.
To make transparent wood, the scientists began with a thin strip of balsa wood veneer and bleached it to remove the polymer called lignin that gives tree cell walls their rigidity. They then infused it with epoxy, which turned the wood clear. The result is a see-through material that lets light through but also blocks some of the sun’s ultraviolet rays and provides privacy.
The researchers’ next step is to improve the material’s mechanical properties to ensure it can be used in buildings. They plan to add a layer of boron nitride to the transparent wood to make it even stronger, which should also enhance its optical performance. They also hope to incorporate functional particles into the transparent wood to give it multiple functions, such as thermal insulation and solar energy harvesting.