Direct writing patterns for electroless plated copper thin film on plastic substrates.

A simple and efficient method is developed to create conductive copper thin films on polymer surfaces. Instead of regular palladium colloid inks, micropatterns of silver nitrate inks, which serve as an activating agent for copper plating, were printed and dried on flexible plastic substrates. The printed plastic sheets were then immersed in an electroless copper plating bath at 55 °C for 2 min to create copper thin films on the printed patterns. The prepared copper films have an electrical conductivity as high as 83% of bulk copper and show good adhesion on PET or PI substrates.