Platinum colloid catalyzed etchingless gold electroless plating with strong adhesion to polymers

Echingless electroless plating (ELP) process that can produce gold thin film with strong adhesion to various polymer films has been developed. We have found that platinum (Pt) colloidal nanoparticles have excellent catalytic activity for ELP. The Pt colloidal nanoparticles can be immobilized via electrostatic interactions on a substrate simply by dipping it into a Pt colloid. Owing to the excellent catalytic property of the Pt nanoparticles, continuous gold thin films can be produced at room temperature using a simple cyanide-free gold electroless plating solution composed of chloroauric acid and hydrogen peroxide. The process requires no surface modifications for the immobilization of the catalyst, and by simple post-annealing the adhesion of the plated films to various polymer films can be improved by three orders of magnitude in comparison to that of “as-deposited” film. The process developed in this work is expected to be an environment-friendly thin metal film deposition process without the use of toxic and hazardous substances.