The film, only a few micron thick, is fabricated by electrospinning a nanofiber mat of polyacrylonitrile (PAN). As it spins out, the fiber coils and intersects itself into many fractal loops which are then electroplated (here any conductive metal could apply, the researchers suggest copper, silver or gold for their high conductivity). The electroplating process actually bonds the fiber's intersections, creating a low-density and conductive copper nanowire-mesh that is nearly fully transparent and highly resilient.
The film exhibited a surface resistivity of 0.42 Ω sq −1 and remained conductive after being stretched by up to 770% and after 1000 cycles of bending to a 5mm radius, they wrote in their Advanced Materials paper "Self-Junctioned Copper Nanofiber Transparent Flexible Conducting Film via Electrospinning and Electroplating".
According to corresponding author Sam Yoon, professor of mechanical engineering at Korea University, the new film beats all previous attempts at making highly transparent and highly conductive thin films.
Because the electrospinning and electroplating are both relatively high-throughput, commercially viable processes, the new film could find its way into flexible and stretchable wearable electronics.