Context

As per a new study, researchers have found a way to make wood transparent without using huge amounts of energy in the process.

About

• Wood is an ancient material humans have been using for millions of years, for the construction of housing, ships and as a source of fuel for burning.
• Wood is essentially composed of two basic ingredients cellulose and lignin:
  • Cellulose is tiny fibers and lignin is the bonds that keep these fibers together and resists compression.
  • Lignin is a glue-like material that bonds the fibres together, a little like the plastic resin in fibreglass or carbon fibre. The lignin also contains molecules called chromophores, which give the wood its brown colour and prevent light from passing through.
• It’s also a renewable source, and one way to capture excess carbon dioxide from the Earth’s atmosphere.

Understanding wood’s lack of transparency

• Wood’s lack of transparency comes from the combination of its two main components- cellulose and lignin.
• The lignin absorbs light, and the presence of chromophores – light activated compounds – in the material makes the wood look brown.
• The fibres in the wood, which mainly comprise cellulose, are hollow tube-like structures.
• The air in these hollow tubes scatters light, further reducing the material’s transparency.

The new method

• The new study demonstrates how to make wood transparent using a simple chemical – hydrogen peroxide – commonly used to bleach hair.
• This chemical modifies the chromophores, changing their structure so they no longer act to absorb light and colour the wood.
• The chemical can be brushed onto the wood, and then activated using light to produce a brilliant white material – blond wood if you like.
• The other reason paper is white is because pores or holes in its structure scatter light, just like the hollow cellulose fibres in wood.
• Filling these fibres with resin reduces that scattering, allowing light to pass through the wood and making it transparent, while retaining its original mechanical properties.

Usgae of transparent wood

• Transparent wood would be much more resistant to accidental breakage
• It could become an alternative to glass in energy efficient buildings, or perhaps coverings for solar panels in harsh environments.