A process of incorporating metal in the form of nanoparticles into the surface layer of a polymeric article and the resultant articles are disclosed. The process includes bringing at least a part of the surface of said article in contact with a solvent mixture that contains (a) water, (b) a carrier conforming to R1—[—O—(CH2)n]mOR2 where R1 and R2 independently one from the other denote a radical selected from the group consisting of linear and branched C1-8 alkyl, benzyl, benzoyl, phenyl and H, n is 2 or 3, and m is 1-35, (c) a metal precursor, and optionally (d) a leveling agent, for a time sufficient to enable infusion of at least some of said metal precursor into said article to obtain an article having a treated surface layer; and treating the surface layer with a reducing agent to produce metal in the form of nanoparticles. The inventive articles prepared by the inventive process exhibit advantageous electrical and/or optical properties.