Influence of configuration of carboxylic acid capping ligands on the salt-induced aggregation of gold clusters

Li, Di; Huang, Yunjie; Li, Jinghong

doi:10.1016/j.jcis.2004.09.024

Cited by 7 publications

(3 citation statements)

References 18 publications

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“…For the second peak appearing at short wavelengths, a small (from 520 to 535 nm) red shift compared to the original peak is registered, and gradually, the peak height decreases. Similar features have been reported , in the literature for aggregation of gold nanoparticles. The trend in Figure c is consistent with the theoretical calculations by Jensen et al for aggregates of spherical particles.…”

Section: Resultssupporting

confidence: 90%

Temperature-Induced Flocculation of Gold Particles with an Adsorbed Thermoresponsive Cationic Copolymer

et al. 2010

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In this article, we report a study of the adsorption of a charged thermoresponsive poly(N-isopropylacrylamide)-block-poly(3-acrylamidopropyl)trimethylammonium chloride) [abbreviated as PNIPAAM24-b-PAMPTMA(+)18] block copolymer onto gold nanoparticles by means of dynamic light scattering (DLS), zeta-potential measurements, cryo-TEM, rheology small-angle light scattering (rheo-SALS), and UV−visible absorbance spectroscopy. At low surface coverage, the cationic copolymer was found to mediate flocculation of the particles at elevated temperatures, whereas at higher polymer concentration, the gold particles were stabilized by the adsorbed copolymer layer. The DLS results showed that the adsorbed polymer was compressed prior to flocculation at elevated temperatures and that the flocs coexisted with single particles. The latter finding was confirmed by cryo-TEM. Rheo-SALS measurements revealed that shear flow disrupted the large flocs formed at higher temperatures. UV−visible absorbance measurements demonstrated that the temperature-induced flocculation process gives rise to a red shift of the localized surface plasmon resonance (LSPR) peak, together with the appearance of a second peak at higher wavelengths.

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Section: Resultssupporting

confidence: 90%

Temperature-Induced Flocculation of Gold Particles with an Adsorbed Thermoresponsive Cationic Copolymer

et al. 2010

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“…This causes a decrease in repulsion between NPs and leads to coagulation. [25,26] Similar to the reported studies of other NP systems, [13,27,28] we observe a dependence of NaCl concentration in the measured SERS signal strength. Although most of the major vibrational modes of 2-MPy adsorbed on nanostars were detectable without addition of NaCl, an increase in the enhanced Raman signal was observed at an optimum concentration of NaCl (ca 50 mM in SERS sample).…”

Section: -Mercaptopyridinesupporting

confidence: 89%

Surface‐enhanced Raman scattering spectroscopy via gold nanostars

Esentürk

Walker

2008

J Raman Spectroscopy

264

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Anisotropic metallic nanoparticles (NPs) have unique optical properties, which lend them to applications such as surfaceenhanced Raman scattering (SERS) spectroscopy. Star-shaped gold (Au) NPs were prepared in aqueous solutions by the seed-mediated growth method and tested for Raman enhancement using 2-mercaptopyridine (2-MPy) and crystal violet (CV) probing molecules. For both molecules, the SERS activity of the nanostars was notably stronger than that of the spherical Au NPs of similar size. The Raman enhancement factors (EFs) for 2-MPy on Au nanostars and nanorods are comparable and estimated as greater than 5 orders of magnitude. However, the enhancement for CV on nanostars was significantly higher than for nanorods, in particular at CV concentrations of 100 nM or lower.

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“…This was because the bare particles aggregated. Usually, this aggregation is caused by the decrease in electrostatic repulsive force between particles according to the increase in ion concentration. , In the dispersion state, floating bare colloids were softly covered with ionic molecules in solution and were kept in a stable dispersion state by their electrostatic repulsive force. In contrast, under a high salt concentration, the covered ions were canceled by the salt ions, and thus the particles aggregated because of the lack of long-distance repulsion.…”

Section: Resultsmentioning

confidence: 99%

Contribution of Nanoscale Curvature to Number Density of Immobilized DNA on Gold Nanoparticles

2009

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We report the curvature size dependence of the density of attached single-stranded DNA (ssDNA) on the surface of gold nanoparticles. The densities of immobilized ssDNA on 10, 20, 30, and 50 nm gold nanoparticles were examined, and we found that the maximum density of the immobilized ssDNA on 10 nm particles was 13 times larger than that on 50 nm particles, which was still 10 times larger than that on flat gold surfaces. This result indicates the importance of curvature in the nanometer-scale attachment of ssDNAs to nanoparticles.

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Influence of configuration of carboxylic acid capping ligands on the salt-induced aggregation of gold clusters

Cited by 7 publications

References 18 publications

Temperature-Induced Flocculation of Gold Particles with an Adsorbed Thermoresponsive Cationic Copolymer

Temperature-Induced Flocculation of Gold Particles with an Adsorbed Thermoresponsive Cationic Copolymer

Surface‐enhanced Raman scattering spectroscopy via gold nanostars

Contribution of Nanoscale Curvature to Number Density of Immobilized DNA on Gold Nanoparticles

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