Influence of the cation alkyl chain length of imidazolium-based room temperature ionic liquids on the dispersibility of TiO2 nanopowders
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The influence of the length of the cation alkyl chain on the dispersibility by ultrasonic treatment of TiO2 nanopowders in hydrophilic imidazolium-based room temperature ionic liquids was studied for the first time by dynamic light scattering and advanced rheology. TiO2 nanopowders had been synthesized by chemical vapor synthesis (CVS) under varied conditions leading to two different materials. A commercial nanopowder had been used for comparison. Characterizations had been done using transmission electron microscopy, X-ray diffraction, nitrogen adsorption with BET analysis, and FT-IR spectroscopy. Primary particle sizes were about 6 and 8 nm for the CVS-based and 26 nm for the commercial materials. The particle size distribution in the dispersion was strongly influenced by the length of the cation alkyl chain for all the investigated powders with different structural characteristics and concentrations in the dispersion. It was found that an increase of the alkyl chain length was beneficial, leading to a narrowing of the particle size distribution and a decrease of the agglomerate size in dispersion. The smallest average nanoparticle sizes in dispersion were around 30 nm. Additionally, the surface functionality of the nanoparticles, the concentration of the solid material in the liquid, and the period of ultrasonic treatment control the dispersion quality, especially in the case of the ionic liquids with the shorter alkyl chain. The influence of the nanopowders characteristics on their dispersibility decreases considerably with increasing cation alkyl chain length. The results indicate that ionic liquids with adapted structure are candidates as absorber media for nanoparticles synthesized in gas phase processes to obtain liquid dispersions directly without redispergation.
KeywordsNanoparticles dispersions Ionic liquids Rheology
The financial support through the NanoEnergieTechnikZentrum (NETZ), an application-focused research project partially financed by the state of North Rhine-Westphalia and the European Union, is kindly acknowledged. We gratefully acknowledge the collaboration with Dr. W. Meyer-Zaika (TEM characterization) at the University of Duisburg-Essen.
- Djenadic R, Winterer M (2012) Nanoparticles from the gasphase: formation, structure, properties. In: Lorke A, Winterer M, Schmechel R, Schulz C (Eds.), Springer, New York, in printGoogle Scholar
- Holbrey JD, Seddon KR (1999) The phase behaviour of 1-alkyl-3-methylimidazolium tetrafluoroborates; ionic liquids and ionic crystals, J Chem Soc Dalton Trans. 2133–2139. doi: 10.1039/A902818H
- Marsh KN, Deev A, Wu ACT, Tran E, Klamt A (2002) Room temperature ionic liquids as replacement for convenitional solvents–a review, Korean J. Chem Eng 19:357–362.Google Scholar
- Nichols G, Byard S, Bloxham MJ, Botteril J, Dawson NJ, Dennis A, Diart V, North NC, Sherwood JD (2002) A review of the terms agglomerate and aggregate with recommendation for nomenclature used in powder and particles characterization. J Pharm Sci 91:2103–2109. doi: 10.1002/jps.10191 CrossRefGoogle Scholar
- Sakhna OV, Goldenberg LM, Stumpe J, Smirnov TN (2007) Surface modified ZrO2 and TiO2 nanoparticles embedded in organic photopolymers for high effective and UV-stable volume halograms. Nanotechnol 18: 105704 (7p.). doi: 10.1088/0597-4484/18/10/105704
- Tokuda H, Hayamizu K, Ishii K, Abu Bin Hasan Susan M, Watanabe M (2004) Physicochemical properties and structures of room temperature ionic liquids.I. Variation of anionic species. J Phys Chem B 108: 16593. doi: 10.1021/jp047480r
- Trung VQ, Huyen DN (2009) Synthesis, properties and application of polyindole/TiO2 nanocomposites. J Phys Conf Ser 187: 012058 (6p.). doi: 10.1088/1742-6596/187/1/012058