No abstract

The internal nanostructure resulting from microphase separation in triblock copolymer films of polyparamethylstyrene-block-polystyrene-block-polyparamethylstyrene, P(pMS-b-Sd8-b-pMS), has been investigated with grazing incidence small angle neutron scattering (GISANS). X-ray reflectivity, grazing incidence small-angle X-ray scattering (GISAXS), optical microscopy and atomic force microscopy (AFM) complement the investigation. The influence of two limiting interfaces present in confinement is compared to the presence of only one surface. GISANS allows for the detection of structures in the very limited sample volume of confined films as well as for a depth sensitivity to probe the near free surface part of bulk films. With respect to the surface a perpendicular oriented lamella is observed. In contrast to the shrinkage of the characteristic lamellar spacing in confinement at the free surface, a slight increase is determined.

Casein films were successfully prepared with the spin-coating technique of aqueous casein solutions on base-treated glass surfaces. The film structure is investigated in real space with optical microscopy and atomic force microscopy and for the first time in reciprocal space with grazing incidence small-angle X-ray scattering (GISAXS). The size of the substructures detected in the film increases with pH from 170 nm (pH 5.1) up to 490 nm (pH 9.4). Dynamic light scattering experiments reveal that the average diameters of casein micelles in solution exhibit the same quantitative increase. This result suggests that the substructures detected in the bulklike films with GISAXS reflect intact casein micelles. However, with thin homogeneous casein films, the micelle size diminishes with decreasing film thickness. This indicates that the moderate pressures introduced by spin-coating force the micelles to rearrange into a more compact structure.

Depositing polymdimethylsiloxane ͑PDMS͒ from an isopropanol solution onto a glass slide surface by wiping with a fuzz-free wipe results in highly ordered structures. Dewetting of the highly diluted PDMS solution and evaporation of the solvent yields nanostructures. The structure is well characterized as polymer nanochannels, separated by a mean distance of 166 nm. The mean height of the shallow channels is 3 nm only. The proof of having aligned structures on very large surface areas with a well defined orientation is performed with a very high resolution grazing incidence small angle x-ray scattering setup.

Phase‐separation structures are installed by solution casting and flow of a binary polymer‐blend solution of polystyrene and poly‐n‐butylacrylate in toluene on silicon. Optical microscopy and scanning‐probe microscopy measurements provide the surface topography. Large‐scale structures are probed with high‐resolution or grazing‐incidence ultra‐small‐angle X‐ray scattering enabled by high reciprocal‐space resolution. Correspondingly, structures of up to 13 µm are resolved. Local‐scale structures are detected with sub‐microbeam grazing‐incidence small‐angle X‐ray scattering, providing a high real‐space resolution of 1 µm. Nanometre‐size cavities are found in the polystyrene‐rich parts of the blend film.