Electroless copper plating of inkjet-printed polydopamine nanoparticles: a facile method to fabricate highly conductive patterns at near room temperature.

Aqueous dispersions of artificially synthesized, mussel-inspired poly(dopamine) nanoparticles were inkjet printed on flexible polyethylene terephthalate (PET) substrates. Narrow line patterns (4 µm in width) of poly(dopamine) resulted due to evaporatively driven transport (coffee ring effect). The printed patterns were metallized via a site-selective Cu electroless plating process at a controlled temperature (30 °C) for varied bath times. The lowest electrical resistivity value of the plated Cu lines was about 6 times greater than the bulk resistivity of Cu. This process presents an industrially viable way to fabricate Cu conductive fine patterns for flexible electronics at low temperature, low cost, and without need of sophisticated equipment.