In a continuation of previous studies, the wetting properties of the hydrophobic bis-ureapropyltriethoxysilylpropyl- terminated polydimethylsiloxane 1000 (PDMSU) sol-gel hybrid, which forms washing-resistant water-repellent finishes on cotton fabrics, were further investigated. The addition of 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES) to PDMSU resulted in a low-energy surface on aluminum. The regenerative nature of the water- and oil-repellent properties of washed PFOTES-PDMSU-finished cotton fabrics was attributed to the surface mobility of the T8 PFOTES based polyhedra.
COBISS.SI-ID: 4133146
The formation of a protective layer from (3-mercaptopropyl)trimethoxysilane (MPTMS) on commercial Sunselect, was studied by non-electrochemical (29Si NMR, IR RA, XPS) and electrochemical (CV and PD) techniques. By simple dip coating of the Sunselect substrate in the MPTMS sol a protective layer was formed, imparting corrosion stability to Sunselect in a salt spray chamber for at least 20 days, outperforming any other sol–gel coating used so far. The most important ?nding was the observation that the applied MPTMS layer did not affect the spectral selectivity.
COBISS.SI-ID: 4211226
Polyurethane based thickness insensitive spectrally selective (TISS) paint coatings deposited on copper substrates were investigated to obtain information about their service lifetime. The activation energy for the degradation process was derived from vibrational band changes recorded in the infrared hemispherical reflectance spectra of TISS paint coatings exposed to different thermal loads. An accelerated test procedure confirmed that TISS coatings could be safely used in solar collectors for at least 45 years.
COBISS.SI-ID: 4117018
A method for the determination of quantum yields of supported photocatalysts by employing an aqueous solution of coumarin and diferent thin TiO2 films was developed. Also a newly defined parameter, the so-called mass efficiency, was introduced. An advantage of using coumarin is easy determination of highly fluorescent 7-hydroxycoumarin. Aqueous solutions of coumarin were iradiated using 365 nm radiation in the presence of titania films. Although Degussa P25 films showed four times higher degradation rates compared to the sol–gel processed, its quantum yield was not more than 2.5 times higher.
COBISS.SI-ID: 1064187
ZnO 1D nanostructures were prepared at modest temperature by homogeneous precipitation from zinc nitrate and urea in a water/ethylene glycol mixture. We established good control of the particles size by growth time and solvent composition, which in turn affects the defect properties of the material. Smaller crystallites with rougher surfaces, exhibited intense deep-defect luminescence and enhanced emission related to the near-surface excitonic recombination. Longer growth times lead to the formation of well-defined nanorods with hexagonal symmetry exhibiting reduced defect emission.
COBISS.SI-ID: 4097050