Thermal stabilization of thin gold nanowires by surfactant-coating: a molecular dynamics study

Huber, S.; Warakulwit, Chompunuch; Limtrakul, Jumras; Tsukuda, Tatsuya; Probst, Michael

doi:10.1039/c1nr11282a

Cited by 17 publications

(17 citation statements)

References 55 publications

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“…Discrepancies of the order 20% between simulations and experiments are expected most notably because of differences in the grafting densities. The value of 3.8 ligands/nm 2 used in the simulations falls within the range of experimental estimates (2–8 ligands/nm 2 ), ,, which suffer from a large degree of currently unavoidable uncertainty . This uncertainty cannot be eliminated experimentally because there is no technique available that would provide the ligand density of individual wires and because it is unknown how broad the standard deviation of the density over many wires is.…”

Section: Resultsmentioning

confidence: 63%

Entropy Can Bundle Nanowires in Good Solvents

et al. 2019

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Surfaces with surface-bound ligand molecules generally attract each other when immersed in poor solvents but repel each other in good solvents. While this common wisdom holds, for example, for oleylamine-ligated ultrathin nanowires in the poor solvent ethanol, the same nanowires were recently observed experimentally to bundle even when immersed in the good solvent n-hexane. To elucidate the respective binding mechanisms, we simulate both systems using molecular dynamics. In the case of ethanol, the solvent is completely depleted at the interface between two ligand shells so that their binding occurs, as expected, via direct interactions between ligands. In the case of n-hexane, ligands attached to different nanowires do not touch. The binding occurs because solvent molecules penetrating the shells preferentially orient their backbone normal to the wire, whereby they lose entropy. This entropy does not have to be summoned a second time when the molecules penetrate another nanowire. For the mechanism to be effective, the ligand density appears to best be intermediate, that is, small enough to allow solvent molecules to penetrate, but not so small that ligands do not possess a clear preferred orientation at the interface to the solvent. At the same time, solvent molecules may be neither too large nor too small for similar reasons. Experiments complementing the simulations confirm the predicted trends.

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Section: Resultsmentioning

confidence: 63%

Entropy Can Bundle Nanowires in Good Solvents

et al. 2019

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“…22 The Universal force eld (UFF) 23 was adopted to perform this simulation. Previous studies 24,25 have shown that UFF provides reliable results for gold based systems. The cut-off radius was chosen to be 15.5 Å and a NVE ensemble was used.…”

Section: Methodsmentioning

confidence: 98%

A DFT study on structure, stabilities and electronic properties of double magnesium doped gold clusters

2014

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Density functional theory (DFT) with PW91PW91 functional has been applied to investigate the structures, relative stabilities and electronic properties of small bimetallic neutral, cationic and anionic Au n Mg 2 (n ¼ 1-5) clusters. The results show that doping with two Mg atoms dramatically affects the geometries of the ground-states of Au n (n ¼ 1-7) clusters. The relative stabilities of the clusters are compared on the basis of average binding energies, fragmentation energies and second order difference of energies.These parameters show even-odd alternation phenomenon. The electronic properties are calculated using hardness values and this suggests that even numbered clusters are more stable than odd counterparts in both bare, as well as doped ones. The nature of the bonding interaction is also investigated using Bader's quantum theory of atoms in molecules (QTAIM), which indicates the presence of covalent bonding in the studied clusters. The population analysis reveals the transfer of electrons from Mg to Au atoms, which is in turn responsible for the enhanced stability of doped clusters.

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“…The melting temperature of the AuUNW was predicted by classical MD simulations to increase with an increase in the attractive force between the surfactants. 35 The modulation of encapsulating shells made of polystyrene-blockpoly(acrylic acid) led to a transformation of straight AuUNWs to circular rings in colloidal solution (Figure 5d). 36 This method gave a structure resembling that of torsion springs (Figure 5e) in which elastic energy is stored.…”

Section: (D) Ac-hrtemmentioning

confidence: 99%

Ultrathin Gold Nanowires and Nanorods

Takahata

Tsukuda

2019

Chem. Lett.

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moving to the University of Tokyo in 2011. His research interest is focused on size-selected synthesis and gas-phase characterization of atomically-precise metal clusters and their catalytic application. Ryo Takahata got his PhD degree in 2018 from the University of Tokyo on the control synthesis and characterization of ultrathin gold nanorods under the supervision of Prof. Tsukuda. In 2018, he joined the research group of Prof. Toshiharu Teranishi at Institute of Chemical Research, Kyoto University as a postdoctral fellow of the Japan Society for the Promotion of Science. His current research interests are precise synthesis of nanostructured materials and elucidation of their optical properties.

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Thermal stabilization of thin gold nanowires by surfactant-coating: a molecular dynamics study

Cited by 17 publications

References 55 publications

Entropy Can Bundle Nanowires in Good Solvents

Entropy Can Bundle Nanowires in Good Solvents

A DFT study on structure, stabilities and electronic properties of double magnesium doped gold clusters

Ultrathin Gold Nanowires and Nanorods

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