Researchers have turned ordinary wood into a material that’s see-through, stronger and more insulating than glass. It also harvests sunlight to power buildings’ lighting, and it looks more natural than frosted glass.
To make wood transparent, scientists bleached away the glue that holds together tiny fibres of cellulose, known as lignin. This removes the molecules that give trees their brown colour and block light.
Strength
Wood has a structural strength that’s difficult to reproduce in synthetic materials, and it has the ability to be shaped into a variety of designs. Transparent wood allows architects to incorporate the beauty of nature into buildings without sacrificing strength or privacy.
Montanari and her colleagues chemically altered balsa wood to make it transparent, removing the lignin that makes the plant rigid. They then filled the resulting microscopic holes with acrylic, which made the wood look a bit like frosted glass. Then they mixed in polyethylene glycol, a so-called phase-change material that melts at 80 degrees Fahrenheit and releases energy when it cools.
The mixture turned the balsa wood into a clear material that retained the original wood patterns. It also has the potential to be functionalized, allowing scientists to add quantum dots to achieve diffused luminescence and other optical properties.
While the mechanical properties of the transparent wood vary depending on the starting material and processing parameters, the results indicate that aesthetically transparent wood can possess integrated advantageous functions such as high optical transmittance, UV-blocking, thermal insulation and mechanical strength. These characteristics would make the material a promising candidate for smart building applications. Its scalability and versatility make it an ideal building material for modern green structures. In addition, the fact that it is made from a renewable material reduces carbon emissions in comparison to other traditional building materials.
Transparency
As a new building material, transparent wood offers many potential applications. Its transparency enables natural light to flood buildings, eliminating the need for artificial lighting and contributing to a more sustainable living and working environment. It also possesses thermal insulation properties that could reduce energy costs. In addition, the material is a renewable resource and produces fewer carbon dioxide emissions than glass or plastic.
Researchers have developed several ways to make transparent wood, including selective delignification and the use of polymer infiltration to eliminate lignin. Using these methods, they have been able to produce aesthetic transparent wood with preserved growth patterns. However, the mechanical properties of this material are still under investigation. It is crucial to determine how much tensile strength and elastic modulus can be obtained from transparent wood. Moreover, it is important to develop techniques for producing thick and large-scale transparent wood structures.
The researchers have found that the cellulose fibres in transparent wood can be aligned and that this alignment enhances the tensile performance of the material. Furthermore, the mechanical properties of the material can be tuned by adjusting the polymer infiltration rate and by varying the cellulose volume fraction. They have also shown that the tensile strength of the material is doubled when it is compressed in the longitudinal direction. This is due to the anisotropic cell wall properties of wood and the geometrical shape of the cellulose fibres.
Durability
Wood is a fantastic building material, but it has some drawbacks. It rots, attracts termites, and blocks light. Scientists at the University of Maryland are working on a way to turn ordinary wood into transparent material that is as strong as glass but lighter and far more eco-friendly. They’ve achieved this by removing the polymer that gives wood its strength and then refilling its microscopic pores with acrylic.
Using a process called delignification, the team bleaches and boils strips of balsa wood to remove the lignin that makes it rigid. Lignin is what gives trees their brown colour and prevents them from being transparent. This isn’t new; it was first developed in 1992 by Siegfried Fink. But in 2015 and 2016, researchers Lars Berglund of Sweden’s KTH Royal Institute of Technology and Liang Bing Hu of the University of Maryland struck a colossal jackpot.
The team replaced the lignin with acrylic, which is less expensive and easier to work with than the chemicals used in previous attempts at creating transparent wood. The new material is still at the prototype stage, but it shows impressive potential. The researchers are now attempting to make it biodegradable and are testing it in computer models of buildings to see how well it holds up under stress and strain. They’re also looking at ways to add electrical and thermal properties to the material.
Sustainability
Wood may seem more at home in log cabins than sleek modern structures, but researchers have developed a transparent form of wood that could bring sustainable and visually captivating design to the construction industry. This special type of timber lets light pass through, absorbs and releases heat, and can bear heavy loads—making it a promising candidate for eco-friendly building materials.
The work began with a botanist’s dream to see inside plants without cutting them open, but it has grown into a research endeavor with far-reaching implications for the future of green architecture. By removing the brown-colored chemicals in wood, such as lignin, scientists have created a material that is weatherproof and fire resistant and three to five times stronger than natural wood.
To make the wood even more durable, Montanari’s team used a bio-based resin—a combination of acrylic acid and limonene, an oil extracted from citrus peels—to impregnate delignified balsa. They also improved the tensile strength of the material by compressing it.
The team’s next goal is to reduce the environmental impact of transparent wood’s production, which relies on a mixture of toxic chemicals and fossil-fuel polymers. The scientists reviewed several methods for producing the material and found that dissolving lignin in an alkaline solution, which they then replaced with epoxy, offered the lowest environmental toll from start to finish. They are also working on a faster process that will enable them to produce larger quantities of the material.