Imagine a world where robots creep up on you: Electric motors just a gentle whir, hard shells changing colour to blend in with their surroundings. Well, there's no need to imagine — it's happened. Researchers form the Guoping Wang of Wuhan University in China have created a robot that changes colour with its surroundings, much like a chameleon. It uses a series of plasmonic displays to achieve the feat.
These displays are glass sheets with a series of holes in them that measure just 50 nanometres in diameter. The team added a gold coating, creating small domes of the precious metal where each hole lies, and then a smear of electrolyte gel with added silver ions was layered on top.
Varying a local electric field causes some silver ions to adhere to the gold surface, the result being a change in colour. Add a sensor to the robot to detect the colour of the surroundings, and the electric field can be tuned so the robot changes colour with its local environment. The research is published in ACS Nano.
The robot's colour changing abilities are modest right now: It can only manage red, green or blue. But in theory if it can create the RGB palette, it can turn any colour it damn well pleases. That will be the next version, then.