pressure increases on the downstream side. A specimen for transmission electron microscopy (TEM) was prepared by sectioning a hybrid nanocomposite containing 10 wt.-% FS at ±100 C in a Reichert-Jung cryo-ultramicrotome. Electron-transparent sections measuring ca. 80 nm thick were imaged with a Zeiss EM902 electron spectroscopic microscope operated at an accelerating voltage of 80 kV and an energy loss of 0 eV. In the past decade, the discovery of fullerenes and carbon nanotubes as new forms of carbon has prompted the opening of an interesting and dynamic new field in physics, chemistry, and materials science because of their remarkable properties and a wide range of potential applications. With the discovery of tungsten disulfide (WS 2 ) and molybdenum disulfide (MoS 2 ) fullerene-like nanoparticles and tubular structures, [1,2] followed by the discovery of boron nitride (BN) nanotubes, [3] it was realized that fullerenes and carbon nanotubes represent only a small subset of a wide class of layered materials that can form C 60 -like particles, tubes, and other interesting morphologies.MoS 2 can be synthesized in a large variety of formsÐparti-cles, nanotubes, [1,2] multiwalled nanotubes [4] and alsoÐlike their carbon cousinsÐin the form of ropes, ribbons, and thin microtubes several micrometers in diameter and millimeters in length. [5] This richness in form promises potential applications going beyond those of carbon nanotubes. Recent theoretical calculations [6] predicted that MoS 2 nanotubes with diameters above 2 nm will all be semiconductors with a bandgap smaller than that of bulk MoS 2 . The size of this gap is a monotonous and smooth function of the tube's diameter and chirality. Zigzag tubes would even have a small direct gap, suggesting that they could be used for optoelectronics i.e., luminescent devices, which is not possible for carbon nanotubes. At this time, there are no theoretical calculations available on MoS 2 nanotubes with subnanometer diameters, such as the ones used in this study. Nevertheless, recent experimental findings indicate that these tubes are most likely all metallic. [7,8] Carbon nanotubes are always produced with a distribution of diameters and chiralities over which there is no real control. As a consequence, they have diverse electronic properties: semiconducting p-and n-tubes are produced along with metallic ones. Even a small change of diameter can drastically alter their electronic properties from metallic to semiconducting. In order to control the electronic properties of carbon nanotubes during production, complete control over their diameters is neededÐa feat that has not been achieved yet. A narrow distribution of diameter will still yield a mixture of metallic and semiconducting tubes. MoS 2 nanotubes on the other hand do not require perfect control over their diameters, because they are predicted to be semiconductors with a monotonous dependence of the bandgap on the diameter. Thanks to this, perfect control over their diameter is not needed: a narrow di...

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Graphene oxide (GO) has recently captured tremendous attention, but only few functionalized graphene derivatives were used as fillers, and insightful studies dealing with the thermal, mechanical, and biological effects of graphene surface functionalization are currently missing in the literature. Herein, reduced graphene oxide (rGO), phosphorylated graphene oxide (PGO), and trimethylsilylated graphene oxide (SiMe3GO) were prepared by the post-modification of GO. The electrostatic interactions of these fillers with chitosan afforded colloidal solutions that provide, after water evaporation, transparent and flexible chitosan-modified graphene films. All reinforced chitosan–graphene films displayed improved mechanical, thermal, and antibacterial (S. aureus, E. coli) properties compared to native chitosan films. Hemolysis, intracellular catalase activity, and hemoglobin oxidation were also observed for these materials. This study shows that graphene functionalization provides a handle for tuning the properties of graphene-reinforced nanocomposite films and customizing their functionalities.

Titanium dioxide coatings were prepared on Si wafers using the sol-gel method. Four different types of coatings with silver nanoparticles (AgNPs) were synthesized. The diameter and surface density of AgNPs were conditioned by the concentration of Ag + ions in the initial solution, time and UV illumination source. The bactericidal activity of AgNPs on the titanium dioxide coatings against the S. aureus strain were calculated as the percentage of the inhibition of bacterial growth after 24 hour incubation of microorganisms at 37 1C on TiO 2 coatings with AgNPs. Control samples were coated with titanium dioxide without AgNPs. We concluded that the titanium dioxide coatings modified with silver nanoparticles had a high antibacterial activity. Moreover, we demonstrated strong dependence between surface areas of AgNPs and inhibition of bacterial growth. The obtained results evidence that the surface area of AgNPs grown on titanium dioxide coatings is a major factor determining their antimicrobial potential.