Transparent conductive nanomaterial has potential for wearables

The film, described in the journal Advanced Materials, is conductive and transparent. It is manufactured by first electrospinning a nanofibre mat of polyacrylonitrile (PAN), where the fibres are about one-hundredth the diameter of a human hair. According to the researchers, the process shoots out the material like a rapidly coiling noodle, which when deposited on to a surface intersects itself a million times.

"The nanofibre spins out in a spiral cone, but forms fractal loops in flight," said Alexander Yarin, a professor of mechanical engineering at UIC and one of the paper’s lead authors. "The loops have loops, so it gets very long and very thin."

This structure also makes the material 92 per cent transparent. “Most of it is holes," said Yarin. "You don't see it."

To make the material conductive, it is spatter-coated with a metal so that it can attract metal ions. It is then electroplated, typically with copper, but alternatively with silver, nickel or gold. The researchers describe the result as a "self-junctioned copper nano-chicken wire" which is bendable and stretchable, and has potential for applications ranging from roll-up touchscreens, wearable electronics, flexible solar cells and electronic skin.