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.

Note: Comparison of grazing incidence small angle x-ray scattering of a titania sponge structure at the beamlines BW4 (DORIS III) and P03 (PETRA III).

Grazing incidence small angle x-ray scattering (GISAXS) is a powerful technique for morphology investigation of nanostructured thin films. GISAXS measurements at the newly installed P03 beamline at the storage ring PETRA III in Hamburg, Germany, are compared to the GISAXS data from the beamline BW4 at the storage ring DORIS III, which had been used extensively for GISAXS investigations in the past. As an example, a titania thin film sponge structure is investigated. Compared to BW4, at beamline P03 the resolution of larger structures is slightly improved and a higher incident flux leads to a factor of 750 in scattered intensity. Therefore, the acquisition time in GISAXS geometry is reduced significantly at beamline P03.

In situ observation of cluster formation during nanoparticle solution casting on a colloidal film.

We present a real-time study of the nanostructuring and cluster formation of gold nanoparticles deposited in aqueous solution on top of a pre-structured polystyrene colloidal thin film. Cluster formation takes place at different length scales, from the agglomerations of the gold nanoparticles to domains of polystyrene colloids. By combining in situ imaging ellipsometry and microbeam grazing incidence small-angle x-ray scattering, we are able to identify different stages of nanocomposite formation, namely diffusion, roughness increase, layer build-up and compaction. The findings can serve as a guideline for nanocomposite tailoring by solution casting.

Grazing incidence wide angle x-ray scattering at the wiggler beamline BW4 of HASYLAB.

We present an upgrade of the available measurement techniques at the wiggler beamline BW4 of the Hamburger Synchrotronstrahlungslabor (HASYLAB) to grazing incidence wide angle x-ray scattering (GIWAXS). GIWAXS refers to an x-ray diffraction method, which, based on the measurement geometry, is perfectly suited for the investigation of the material crystallinity of surfaces and thin films. It is shown that the overall experimental GIWAXS setup employing a movable CCD-detector provides the capability of reliable and reproducible diffraction measurements in grazing incidence geometry. Furthermore, the potential usage of an additional detector enables the simultaneous or successive measurement of GIWAXS and grazing incidence small angle x-ray scattering (GISAXS). The new capability is illustrated by the microbeam GIWAXS measurement of a thin film of the conjugated polymer poly(3-octylthiophene) (P3OT). The investigation reveals the semicrystalline nature of the P3OT film by a clear identification of the wide angle scattering reflexes up to the third order in the [100]-direction as well as the first order in the [010]-direction. The corresponding microbeam GISAXS measurement on the present morphology complements the characterization yielding the complete sample information from subnanometer up to micrometer length scales.