So, what if I told you there had been a technological breakthrough and we could have wooden windows?
No, I don’t mean wooden window frames I mean wooden windows!
Wood is capable of being made thin, lightweight, strong, insulating and hence energy efficient where glass is a very bad insulator
But wood is not transparent? How can it be used for windows?
Researchers from the University of Maryland published in ScienceAdvances recently that they have succeeded in making wood transparent.
That is very interesting!
Wood has very good mechanical properties, even when it is thin. Wooden windows would make a sustainable solution and increase the potential for building sustainable wooden homes. But until quite recently, methods for making transparent wood were quite energy intensive; and they used harmful products.
The article in ScienceAdvances now shows a more sustainable method for making wooden windows.
Here comes the technical bit!
The main components of wood are cellulose and lignin. Lignin absorbs light mainly in its ‘chromophores’. These are chemical structures that absorb light (that’s why wood is non-transparent) and lend wood its brownish colour. Cellulose mainly consists of hollow tubes, that scatter light and add to the non-transparent properties of ordinary wood. In earlier work, researchers tried to remove the lignin completely, and replace this with some sort of resin.
But lignin removal requires harmful products and it weakens the material. The University of Maryland researchers have shown now that lignin removal isn’t necessary. Instead, they brush hydrogen peroxide (H2O2) on the wood, quite like when bleaching paper pulp.
This substance penetrates into the wood and changes the structure of the chromophores, so they no longer absorb light. Then they expose the wood to UV light; this finishes the work of hydrogen peroxide, turning wood to become white.
Finally, they infiltrate the wood with a special epoxy, that fills the cavities in the cellulose tubes. These now no longer scatter the light. This results in a transparent material that still has the original mechanical properties of wood.
This new technique could open up a whole new area of applications.
We are only at the research stage so far; industrial applications may take some time to develop. Researchers need to optimise the reaction with wood and incorporate it into an industrially automated process
Would you buy wooden windows?