Interaction of neutral hydrogen atoms with the layer of hydrogenated carbon–tungsten composite was studied. A 1 μm thick layer was prepared by sputter deposition from C and WC-targets in Ar/C2–H2 gas mixture. After deposition the samples were treated in weakly ionized highly dissociated hydrogen plasma created in a microwave discharge at a power of 1 kW. The gas flow was 13 l/h and pressure was 90 Pa. Temperature of the samples during treatment was about 850 K. After plasma treatment the samples were analyzed by AES (Auger electron spectroscopy) depth profiling, XPS (X-ray photoelectron spectroscopy) and SEM (scanning electron microscopy). It was found that during hydrogen plasma treatment selective etching of the C–W layer occurred. Carbon was preferentially removed from the C–W layer, and after about 10 min of treatment practically only tungsten with a huge porosity was detected.
COBISS.SI-ID: 24572711
Small angle X-ray scattering (SAXS) is employed to characterize the inner structure and shape of aqueous nanocrystalline cellulose suspensions using the generalized indirect Fourier transformation (GIFT). The use of the GIFT approach provides a single fitting procedure for the determination of intra- and interparticle interactions due to a simultaneous treatment of the form factor P(q) and the structure factor S(q). Moreover, GIFT allows for the determination of particle charges and polydispersity indices. As test material, aqueous nanocrystalline cellulose suspensions (aNCS) prepared by the H2SO4 route have been investigated and characterized (SAXS, dynamic light scattering, zeta potential).
COBISS.SI-ID: 16700438
Three industrially-prepared (via the sulphate synthesis process) and commercially-available nanoTiO2 colloidal suspensions were coated on polyester fabric using the conventional pad-dry-cure procedure, in order to enhance fabric functionalities by imparting self-cleaning and UV-protection ability. Various characterization techniques, i.e. transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), and UV/Vis spectroscopy of the suspensions revealed the presence of anatase TiO2 spherical-shaped nanoparticles of different crystallite sizes, as well as its prominent absorption capacity within the UV region. Scanning electron microscopy (SEM) was adopted to analyse the morphological structure of nanoTiO2-modified PES fabrics. Furthermore, the photocatalytic activity was investigated through the discolourations of red wine and red beet stains under two types of light sources, i.e. direct day light and artificial UV light, by means of a spectrophotometry. The UV-protective properties were also evaluated by calculating the ultraviolet protective factors of individual coated fabric. The obtained results show acceptable blocking properties against UV-rays, as well as the adequate self-cleaning abilities of TiO2-modified PES fabrics as governed by the types and concentrations of applied TiO2 suspension.
COBISS.SI-ID: 16802582
The aim of the presented work was to study the effects of TiO2–SiO2 nanoparticles on the hydrophilicity as well as colouration ability of polyester fabric during high-temperature disperse dyeing. Various analytical techniques were employed to characterize three TiO2–SiO2 dispersions with different SiO2 weight percent. In addition, one-bath exhaustion procedure was accomplished by combining TiO2 dispersions and three disperse dyes in two concentrations, respectively. Finally, the dyed/nano-upgraded samples were subjected to artificial UV light with the intention of establishing any undesired photo-fading behaviour of applied dyes on account of TiO2 presence. The results provided evidence of enhanced wettability at low SiO2 content, and on the other hand, pale depth of shade when the nanoTiO2-hybrides were attended, regarding the type of dye and its concentration. Moreover, UV irradiation significantly influenced the hue, brightness, chroma, and colour strength, although the higher SiO2 amount suppressed the photocatalytic activity of nanoTiO2 and thus, diminished the oxidative dye-fading.
COBISS.SI-ID: 17861142
Industrial processes are most often limited in the means of production conditions, e.g., chemical agents’ selection and consumption, and time and energy conditions. In the present work, we succeeded in synthesizing a homogeneous silica layer on titanium dioxide (TiO2) core using moderate time and temperature conditions. The structure of the surface coated pigmentary TiO2 was characterized by scanning electron microscopy, transmission electron microscopy, and EDS. In our research isoelectric point (IEP) of TiO2 was determined, which occurred when the solution pH was ~4. In the meantime, the precipitation of SiO2 on TiO2 surface resulted in the shift of IEP. In addition, Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller analysis were applied in order to determine differences in surface microstructure. Coating parameters were optimized to attain desired morphology of precipitated Si-hydroxide, which in turn provides improvements in one or more important performance properties such as hiding power efficiency, which was determined by the means of UV–Vis light transmittance.
COBISS.SI-ID: 18368565