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Novel catalytic surfaces can be prepared by in situ synthesis of metal nanoparticles (NPs) inside polymer brush systems. To gain more control over the properties of these nanocatalysts, it is important to quantify their distribution inside the polymer brush and understand their formation process better. Here, measurements of the distributions of Pt and Pd NPs within poly(2-vinylpyridine) (P2VP) brushes are reported. The amount of surface accumulation and the extent of penetration of the two metal NPs into the brush layer are determined using X-ray reflectivity measurements. Quantitative analysis of the data reveals a significant difference between the distributions of the two NP species. Pd NPs exhibit higher accumulation at the surface and larger penetration depth within the brush. This difference in behavior is attributed to the different adsorption mechanisms exhibited by the two metal ions. Whereas Pt ions adsorb to the polymer brush via ionic bonds, Pd ions form complex coordination bonds. The different distributions of the NPs within the polymer brush are related to the previously investigated catalytic activity of these systems. The reported unusually high specific activity of Pt hybrid brushes, as compared with Pd ones, can now be explained by buried Pd NPs that do not take part in the catalytic reaction. [ABSTRACT FROM AUTHOR]

The combinatorial method of quartz crystal microbalance coupled with spectroscopic ellipsometry can be used to follow the in situ synthesis of catalytically active palladium nanoparticles in polymer brushes in situ. By combining these two orthogonal techniques, it is possible to thoroughly characterize the thickness, composition, optical, and mechanical properties of nanoscopic thin films. [ABSTRACT FROM AUTHOR]

Novel catalytically active nanocomposite surfaces are fabricated by in situ synthesis of palladium or platinum nanoparticles inside poly(2-vinylpyridine) (P2VP) brushes, used as a nano-reactor. Focusing on the revelation of the interaction of the metal species with P2VP, the immobilization is investigated by X-ray photoelectron spectroscopy (XPS), attenuated total reflection Fourier transform IR (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), as well as scanning electron microscopy (SEM) and transmission electron micro­scopy (TEM). Homogeneous distribution of nanoparticles is achieved. The mechanism of nanoparticle formation is investigated by study­ing the influence of particular reaction parameters and the catalytic activity of the nanocomposites is confirmed using a model reaction. [ABSTRACT FROM AUTHOR]