Dispersions of Various
Titania Nanoparticles in Two
Different Ionic Liquids
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Abstract
The dispersibility of different lab-made and commercial
TiO<sub>2</sub> nanoparticles prepared by gas-phase processes in room
temperature
ionic liquids was for the first time studied by dynamic light scattering
and advanced rheology. The characterization of the nanopowders has
been done with transmission electron microscopy, X-ray diffraction
analysis, nitrogen adsorption, and Brunauer–Emmett–Teller
(BET) analysis and FT-IR spectroscopy. The colloidal stabilities of
the resulting dispersions were strongly influenced by particle characteristics
such as aggregation level, mean particle size, and surface functionality.
The period of the ultrasound treatment, the powder concentration in
the dispersion, and the hydrophilicity of the ionic liquid were also
important influences. It was found that most types of powders disperse
better in the hydrophilic ionic liquid because of the hydroxyl groups
and adsorbed water present on the powders' surfaces. The best dispersions
over a broader concentration range were obtained for a lab-made powder
produced by chemical vapor synthesis (aerosol method) which had the
smallest nonaggregated particles