UK university develops material that changes colour under force
08/06/2016
Working alongside researchers from Germany, the scientists have managed to manufacture on an industrial scale a film made from this material, which is known as ‘polymer opals’. The process begins by the researchers growing plastic nano-spheres, which are then dried out into a congealed mass. Sheets containing these spheres are then bent around rollers and this forces them into perfectly arranged stacks. Changing the sizes of the starting nano-spheres makes material of different colours and different wavelengths of light that it reflects. The materials rubber-like consistency allows it be twisted and stretched causing the spacing between the spheres to change and altering the material’s colour.
The university thinks that the material could have a wide range of applications including banknote security or in smart clothing. It says that polymer opals produce brighter colour at lower costs than the holograms normally seen on banknotes so forgery would be more difficult.
The technology could also be of use to the textile industry. Professor Jeremy Baumberg, who worked on the project, says it could offer an alternative to using potentially harmful chemicals to produce colour in textiles. The polymer opals can be bonded to a polyurethane layer and then onto any fabric.
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