Scientists have developed a material which could help in the fight against counterfeit banknotes and passports.
The pigment-free, intensely-coloured polymer materials could provide new anti-counterfeit devices on passports or banknotes because they are difficult to copy, researchers said.
The polymers do not use pigments but instead exhibit intense colour due to their structure, similar to the way nature creates colour for beetle shells and butterfly wings.
The colour also changes depending on the viewing angle and scientists believe the new system could have huge advantages in terms of cost, processing and colour selection compared with existing systems.
The complexity of the chemistry involved in making the polymer means they are very difficult for fraudsters to copy, making them ideally suited for use on passports or banknotes.
The academics used Diamond Light Source, the UK's national synchrotron science facility in Oxfordshire, to probe the ordered, layered structures using high power X-rays.
This helped them understand how the colours were formed, and how to improve the appearance.
Dr Andrew Parnell, from the University of Sheffield's department of physics and astronomy, said: "Our aim was to mimic the wonderful and funky coloured patterns found in nature, such as peacock feathers.
"We now have a painter's palette of colours that we can choose from using just two polymers to do this. We think that these materials have huge potential to be used commercially."