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This communication is focused on the synthesis, characterization and experimental proof of the mechanism of antimicrobial activity of powders from the molybdenum-tungsten-oxygen (Mo-W-O) system. Materials with a discrete ratio of Mo/W ranging from 100% MoO

This study demonstrates the formation of barrier-type anodic films in a phosphate buffer (pH 8.4) on thermally evaporated aluminium-holmium alloys covering a 2.0–12.0 at.% Ho compositional spread. Scanning x-ray diffraction and scanning electron microscopy reveal that structure and morphology of the parent alloys library drastically change above 6.5 at.% Ho. Anodic films were formed when the as-evaporated alloys were stepwise anodized potentiodynamically to a maximum of 10 V in phosphate buffer regardless of film composition and morphology. Simultaneous in-situ electrochemical impedance spectroscopy discloses a good co-relation between film thickness and formation factor with the composition and morphology of parent alloys, suggesting a strong influence of holmium concentration on the structure, morphology of parent alloys as well as on the dielectric properties of resulting anodic films. Inductively coupled plasma optical emission spectroscopy measurements allowed a quantitative determination of the dissolved species during anodization.

A facile route for the synthesis of PHEMA hydrogel incorporating anatase nanoparticles is presented. The hydrogel features a refractive index of 1.527 and high transparency throughout the visual spectral range. Saturn rings have been machined in order to investigate the workability of the material and its potential applicability as intraocular lens implant. The resulting lenses feature high surface quality, foldability, and shape memory which makes them suitable for implantation via extracapsular cataract extraction.

An aluminium-samarium binary library with a varying Sm concentration between 4 to 14 at.% was produced using a thermal co-evaporation technique. Morphological and crystallographic characterization of the parent metal alloys revealed compositionally dependent surface structure and atomic arrangements. Grains resembling pure Al on the surface slowly disappeared with increasing Sm content and above 8 at.% Sm nucleation of the AlSm2 intermetallic phase was observed. Scanning droplet cell microscopy was used for a comprehensive electrochemical characterization along the Al-Sm compositional gradient. Anodic oxide formation under high field conditions was discussed for alloys below the compositional threshold of 8 at.% Sm. Above this threshold a continuous increase of Sm dissolution during anodization with increasing Sm concentration was proven by inductively coupled plasma optical emission spectroscopy. Coulometry followed by EIS allowed mapping of the oxide formation factors and oxide electrical permittivity as material constants for single Al-Sm alloys. A small increase of both material constants for alloys below the compositional threshold described the Sm contribution to the anodization process. An apparent enhancement of their values at alloys above the threshold was directly attributed to the increased Sm dissolution rates reaching values of 2 ng cm−2 s–1 at 12 at.% Sm.

A thin film dysprosium-magnesium-zinc combinatorial library has been deposited using a thermal co-evaporation technique. Scanning EDX, XRD, SEM and XPS were used to investigate the structure, surface morphology and species present. The entire library was found to be amorphous and morphological changes were visible by minor additions of Dy (approximately 1 at.%) and medium to high Zn contents (> 20 at.%). Open circuit potential, electrochemical impedance spectroscopy and potentiodynamic polarization measurements revealed a higher corrosion resistance for Zn-poor alloys (

The lanthanoids are a consequent series of elements and with their 3 valence electrons they prefer the trivalent state while continuously filling the inner f-shell. A specific energetically stabilizing effect is observed so that the empty, the half-filled or the completely filled f-shell show extraordinary low energies resulting in a stabilizing effect so that neighboring valence states such as divalent or tetravalent can be also observed. Interestingly with increasing atomic number the atomic and ionic radii decrease - counter intuitively. As a result of the electronic shielding effect of the f-electrons the so-called lanthanoid contraction is observed. Aluminium is another element that forms preferentially trivalent ions. A combinatorial approach in which aluminium-lanthanoid-alloys are investigated both in terms of the alloy itself but in particular for the passivity based on the mixed oxides forming on these alloys is presented here. A complex attempt was made not only to cover the various elements themselves but also their concentration ratios in material thin film libraries. These material libraries are prepared in a large preparation and analysis cluster the so-called CALMAR. Asymmetrical physical codeposition of the constituting elements is used in HV and UHV chambers to prepare these libraries and to characterize them by a scanning EDX system as well as XRD. Theoretical considerations were used to compute the Pourbaix diagrams. Also phase diagrams of the Al-Lx alloys are consulted to identify intermetallics and regions of solid solution mixing. Passivation studies were performed using a flow type scanning droplet cell microscope FT-SDCM. This method allows the subsequent stepwise anodization and electrochemical impedance spectroscopy characterisation of a single spot of a library having a single composition. Spatial scanning of the library yields detailed information of the systematically changing alloy compositions. To understand not only the anodic oxide formation but also the chemical and electrochemical reactions during anodization a complementary investigation of the electrolyte is performed using inductively coupled plasma spectrometry. Various lanthanoids were mixed with aluminium and electrochemically studied. It is found that the large ionic radii mismatch is likely to cause strong amorphisation. In this way already binary alloys were found to form metallic glasses in some regions i.e. for some compositions. This has a strong impact on the passivation behavior and electrochemical stability. Some distinct intermetallic compounds in these binary alloys were found with the expected consequence for the stability.