World Bulletin / News Desk
Scientists have found nature's way of creating colour that never fades, a technique they say could replace pigments used in industry with natural plant extracts in products from food colouring to security features in banknotes.
Layers of cellulose that reflect specific wavelengths of light - 'structural colour' found in peacock feathers, scarab beetles and butterflies - make a particularly intense blue in the Pollia condensata plant, scientists say.
Samples of the fruit in plant collections dating back to the 19th century had not lost any shine or intensity, they found.
"By taking inspiration from nature, it is possible to obtain smart multifunctional materials using sustainable routes with abundant and cheap materials like cellulose," said University of Cambridge physicist Silvia Vignolini.
"It is 10 times more intense and bright than any colour achieved with a pigment," said Vignolini, who led the study with plant scientist Beverley Glover.
Although the fruit has no nutritional value, birds were attracted by its bright colour, possibly as a decoration for their nests or to impress mates, helping in seed dispersal.
"This obscure little plant has hit on a fantastic way of making an irresistible, shiny, sparkly, multi-coloured, iridescent signal to every bird in the vicinity, without wasting any of its precious photosynthetic reserves on bird food," said Glover.
And, unlike pigments, structural colour does not fade over time as it is not broken down by absorbing light.
"Edible, cellulose-based nanostructures with structural colour can be used as substitutes for toxic dyes and colorants in food," said Vignolini. The paper industry is already set up to extract and use cellulose and its processes could also be adapted for security labelling or cosmetics, she said.
"Cellulose-based structures have a really strong optical response and are completely inert in the human body," she said.
Another advantage of the technique is that the desired colour can be achieved by adding layers in the structure to reflect different wavelengths, rather than buying new pigment.
Similar research by Peter Vukusic at Exeter University into the structure that creates colour in butterfly wings has spawned a pigment-free photonic make-up from French cosmetics company L'Oreal.
"I saw how brilliant optically some of these structural colours are," Vukusic told Reuters. "Some species collected as far back as the eighteenth century are as bright today as freshly hatched butterflies."
Vukusic said although some car companies, including BMW , have also exploited the phenomenon to produce iridescent paint that changes colour when viewed from different angles, "this is nothing compared to what you see in nature".
He said that if production challenges can be overcome, the abundance of cellulose - the basis of most green plant material - makes it a material with great potential.
The research is published today in the scientific journal Proceedings of the National Academy of Sciences.
Vast quantities of rare gas hint at Earth’s past, could power planet’s future
Global temperatures at record highs; Arctic sea ice levels at record lows
23-year-old researcher to create computer models of brain structures in world's largest particle physics laboratory
New mobile game already used by 5 percent of Android users in US
The $180m radio telescope with size of 30 football fields is expected to be operational by September, state media says.
The 41st Committee on Space Research (COSPAR) Scientific Assembly will take place between July 30 and August 7 at the Istanbul Congress Center
India launches largest successful satellite mission as it continues focus on space reseach
Court-ordered payout comes on same day company pulls fake refugee rescue app
Driverless minibus called Olli, capable of carrying up to 12 people, released by IBM and Local Motors
Popular social media network Twitter has broken, with the network's website and mobile apps inaccessible for users worldwide
In April, Germany officially announced a new incentive and investment program to accelerate the adoption of electric cars in the country.
Findings based on laser technology challenge previous theories on urban, water systems around temple complexes
With clean energy, ‘you can reconcile ecology and economy’, says Solar Impulse navigator
A blind Muslim Microsoft engineer has unveiled an AI-powered project that helps him 'see' the world