Polymer-coated PtCo nanoparticles deposited on diblock copolymer templates: Chemical selectivity versus topographical effects

Metal-polymer hybrid films are prepared by deposition of polymer-coated PtCo nanoparticles onto block copolymer templates. For templating, a thin film of the lamella-forming diblock copolymer poly(styrene-b-methyl methacrylate) P(S-b-MMA) is chemically etched and a topographical surface relief with 3 nm height difference is created. Two types of polymer-grafted PtCo nanoparticles are compared to explore the impact of chemical selectivity versus the topographical effect of the nanotemplate. A preferable wetting of the polystyrene (PS) domains with poly(styrenesulfonate) (PSS)-coated PtCo nanoparticles (instead of residing in the space between the domains) is observed. Our investigation reveals that the interaction between PSS-coated nanoparticles and PS domains dominates over the topographical effects of the polymer surface. In contrast, a non-selective deposition of poly(N-vinyl-2- pyrrolidone) (PVP)-coated PtCo nanoparticles and the formation of large metal-particle aggregates on the film is observed. The chemical selectivity and topography characteristics of a polymer nanotemplate on the deposition behavior of specially synthesized polymer-coated nanoparticles are investigated. The results indicate that the selectivity of the poly(styrenesulfonate) (PSS)-coated metal nanoparticles towards the PS domains of the nanostructured film dominates over the topographical effects of the surface.