Colour-changing e-skin developed; can have robotics uses

Chinese researchers have developed a user-interactive electronic skin that can change colour -- an ability associated with animals such as chameleons, octopuses and squid. The changes are perceptible to the human eye without much strain.

Though science has been able to replicate these abilities with artificial skin, the colour changes are often only visible to the naked eye when the material is put under huge mechanical strain.

"This user-interactive e-skin should be promising for applications in wearable devices, robots and prosthetics in the future," the study mentioned.

The researchers employed flexible electronics made from graphene, in the form of a highly-sensitive resistive strain sensor, combined with a stretchable organic electrochromic device.

"To obtain good performance with a simple process and reduced cost, we designed a modulus-gradient structure to use graphene as both the highly sensitive strain-sensing element and the insensitive stretchable electrode of the ECD layer," said Tingting Yang from Tsinghua University, in a paper published in the journal 2D Materials.

The researchers found that subtle strain -- between zero and 10 per cent -- was enough to cause an obvious colour change, and the RGB value of the colour quantified the magnitude of the applied strain.

The study noted that the capability for interactive colour changes with such a small strain range has been rarely reported before.