Thirty years ago, a botanist in Germany wanted to see the inner workings of woody plants without dissecting them. Siegfried Fink succeeded in creating transparent wood by bleaching pigments in plant cells and published his technique in a wood technology journal. For the first time since 1992, Lars Berglund became interested in this topic because he was interested in creating a more durable alternative to transparent plastic.
What is transparent wood used for and how is it produced?
After years of experiments, research is now beginning to bear fruit. Transparent wood may soon find use in super-strong displays for smartphones; in soft, bright lighting fixtures; and can even be used as an additive to structural features such as color-changing windows.
“I really believe that this material has a promising future,” says Qiliang Fu, a wood nanotechnologist who works as a graduate student in Berglund’s laboratory at Nanjing University of Forestry in China.
The wood consists of countless small vertical channels that resemble a tight bundle of reeds bound together with glue. These tube-shaped cells transport water and nutrients throughout the tree, and when the tree is harvested and moisture evaporates, air pockets are left behind.
To create transparent wood, scientists first need to replace or get rid of the glue called lignin, which holds bundles of cells together and provides trunks and branches with much of their earthy brown hue. After the lignin is bleached or otherwise removed, a milky white skeleton of hollow cells remains.
This skeleton is still opaque because the cell walls bend light to a different degree than the air in the cell pockets; This value is called the refractive index. Filling the air pockets with a substance such as epoxy resin, which bends light to a similar degree as cell walls, makes the wood transparent.
Highlighting the properties of transparent wood in the 2023 Annual Review of Materials Research, Hu said, “The results are spectacular; “A piece of wood can be as strong as glass,” he said. So what do you think about this issue? You can share your thoughts with us in the comments section.
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