Stein, Benjamin, Zopes, David, Schmudde, Madlen, Schneider, Ralf, Mohsen, Ahmed, Goroncy, Christian, Mathur, Sanjay and Graf, Christina (2015). Kinetics of aggregation and growth processes of PEG-stabilised mono- and multivalent gold nanoparticles in highly concentrated halide solutions. Faraday Discuss., 181. S. 85 - 103. CAMBRIDGE: ROYAL SOC CHEMISTRY. ISSN 1364-5498
Full text not available from this repository.Abstract
5-6 nm gold nanoparticles were prepared by hydrolytic decomposition of [NMe4]-[Au(CF3)(2)] and functionalized in situ with mono-and multivalent thiolated PEG ligands. Time-dependent changes of the nanoparticles were monitored in aqueous NaCl, NaBr, and NaI solutions by UV-Vis spectroscopy, TEM, and HRTEM. The purely sterically protected particles are stable in <= 1 M NaCl and NaBr solutions, regardless of the valence of the ligands. At higher concentrations (>= 2 M), the monovalent stabilized particles show minor reaction limited colloidal aggregation. In NaBr but not in NaCl solutions a minor Ostwald ripening also occurs. The divalent stabilized particles remain colloidally stable in both halide solutions, even if the temperature is raised or the concentration is increased above 2 M. In <= 1 M aqueous NaI solutions the particles remain stable. Above, the monovalent stabilized particles undergo an oxidative reaction, resulting in a time-dependent shift and broadening of the absorbance spectrum. Finally, this process slows down while the width of the spectra slightly narrows. The kinetics of this process can be described by a two-step sigmoidal process, comprising a slow induction period where active species are formed, followed by a fast growth and aggregation process. The increasing concentration of fused structures from the aggregates during this process results in a narrowing of the size distributions. The divalent stabilized particles show only some minor broadening and a slight shift of the absorbance spectra in <= 3 M NaI solutions. These observations confirm the excellent stability of the multivalent stabilized particles from this chloride-free particle synthesis.
Item Type: | Journal Article | ||||||||||||||||||||||||||||||||||||
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URN: | urn:nbn:de:hbz:38-416295 | ||||||||||||||||||||||||||||||||||||
DOI: | 10.1039/c5fd00024f | ||||||||||||||||||||||||||||||||||||
Journal or Publication Title: | Faraday Discuss. | ||||||||||||||||||||||||||||||||||||
Volume: | 181 | ||||||||||||||||||||||||||||||||||||
Page Range: | S. 85 - 103 | ||||||||||||||||||||||||||||||||||||
Date: | 2015 | ||||||||||||||||||||||||||||||||||||
Publisher: | ROYAL SOC CHEMISTRY | ||||||||||||||||||||||||||||||||||||
Place of Publication: | CAMBRIDGE | ||||||||||||||||||||||||||||||||||||
ISSN: | 1364-5498 | ||||||||||||||||||||||||||||||||||||
Language: | English | ||||||||||||||||||||||||||||||||||||
Faculty: | Faculty of Mathematics and Natural Sciences | ||||||||||||||||||||||||||||||||||||
Divisions: | Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Inorganic Chemistry | ||||||||||||||||||||||||||||||||||||
Subjects: | no entry | ||||||||||||||||||||||||||||||||||||
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Refereed: | Yes | ||||||||||||||||||||||||||||||||||||
URI: | http://kups.ub.uni-koeln.de/id/eprint/41629 |
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