A new type of material made by stacking ‘microscopic marbles’ could lead the way to new applications such as ‘smart’ clothing. Researchers led by a team at the University of Cambridge have developed a roll-to-roll method of organising transparent nano-spheres — known as ‘polymer opals’ — into regular layers, producing intriguing materials which scatter light into intense colours that change hue when twisted or stretched.

A spokesman said: “The technique stems from efforts to recreate some of the brightest colours in nature, which can be found in opal gemstones, butterfly wings and beetles. These materials get their colour not from dyes or pigments, but from the systematically ordered micro-structures they contain.”

To make the opals, the team starts by growing vats of transparent plastic nano-spheres, which are solid in the middle but sticky on the outside; these are then dried out into a congealed mass.

Professor Jeremy Baumberg said: “By bending sheets containing a sandwich of these spheres around a series of rollers, the balls are forced into perfectly arranged stacks, by which stage they have intense colour, Finding a way to coax objects a billionth of a metre across into perfect formation over kilometre scales is a miracle, but spheres are only the first step, as it should be possible to crete more-complex architectures on tiny scales.”

Cambridge Enterprise, the university’s commercialisation arm is helping to promote the material. It has been contacted by more than 100 companies interested in using polymer opals. A new spin-out called Phomera Technologies has been founded, which will look at ways of scaling-up production of these polymer opals.