Copper-fluoropolymer (Cu-CFx) nano-composite films are deposited by dual ion-beam sputtering. The extensive analytical characterization of these layers reveals that inorganic nanoparticles composed of Cu(II) species are evenly dispersed in a branched fluoropolymer matrix. In particular, X-ray photoelectron spectroscopy has been employed to study the surface chemical composition of the material and to assess how it changes on increasing the copper loading in the composite. Transmission electron microscopy reveals that the copper nanoclusters have a mean diameter of 2-3 nm and are homogeneously in-plane distributed in the composite films. Electrothermal atomic absorption spectroscopy has been used to study the kinetics of copper release in the solutions employed for the biological tests. The Cu-CFx layers are employed as bioactive coatings capable of inhibiting the growth of target microorganisms such as Saccharomyces cerevisiae, Escherichia coli, Staphylococcus aureus, and Lysteria. The results of the analytical characterization enable a strict correlation to be established among the chemical composition of the material surface, the concentration of copper dissolved in the microorganisms broths, and the bioactivity of the nano-structured layer.

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Carbon nanotubes (CNTs) are fascinating one-dimensional molecular structures that can be either metallic or semiconducting, depending on their diameter and helicity. [1±3] In order COMMUNICATIONS

Physical properties of zinc oxide films deposited by dual-ion-beam sputtering are analyzed to point out the performance of this technique for the deposition of this material. The films are deposited by sputtering a zinc oxide target with an argon-ion beam, while a second low-energy beam, the assistance ion beam, impinges directly on the growing films. Results are presented for ZnO films deposited at room temperature with different oxygen/argon ratios in assistance ion beam and different sputtering ion-beam currents. Elemental, structural, and electrical analyses have been performed on films. All the films show the typical crystallographic orientation, with the c axis perpendicular to the substrate. The oxygen percentage in the assistance ion beam plays an important role in controlling the electrical resistivity of the films.

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