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Ultrasonic-aided fabrication of gold nanofluids.

Chen HJ, Wen D - Nanoscale Res Lett (2011)

Bottom Line: The ultrasonication technique is found to be a very powerful tool in engineering the size and shape of GNPs.Subsequent property measurement shows that both particle size and particle shape play significant roles in determining the effective thermal conductivity.A large increase in effective thermal conductivity can be achieved (approximately 65%) for gold nanofluids using plate-shaped particles under low particle concentrations (i.e.764 μM/L).

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Engineering and Materials Science, Queen Mary University of London, London, UK. d.wen@qmul.ac.uk.

ABSTRACT
A novel ultrasonic-aided one-step method for the fabrication of gold nanofluids is proposed in this study. Both spherical- and plate-shaped gold nanoparticles (GNPs) in the size range of 10-300 nm are synthesized. Subsequent purification produces well-controlled nanofluids with known solid and liquid contents. The morphology and properties of the nanoparticle and nanofluids are characterized by transmission electron microscopy, scanning electron microscope, energy dispersive X-ray spectroscope, X-ray diffraction spectroscopy, and dynamic light scattering, as well as effective thermal conductivities. The ultrasonication technique is found to be a very powerful tool in engineering the size and shape of GNPs. Subsequent property measurement shows that both particle size and particle shape play significant roles in determining the effective thermal conductivity. A large increase in effective thermal conductivity can be achieved (approximately 65%) for gold nanofluids using plate-shaped particles under low particle concentrations (i.e.764 μM/L).

No MeSH data available.


The colors of 90-nm gold nanoplates (left) and 90-nm GNPs (right).
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Figure 7: The colors of 90-nm gold nanoplates (left) and 90-nm GNPs (right).

Mentions: Different colors of gold nanofluids, shown in Figure 5, are due to the effect of surface plasmon resonance (SPR), an optical phenomenon arising from the collective oscillation of conduction electrons [18]. The SPR is a size-dependent phenomenon, which renders different colors for different gold nanofluids. For spherical nanoparticles, the color of gold dispersion is dark blue and purple-red for 15-nm and 90 nm particles, respectively. For gold nanoplates, Figure 5 also reveals a size-dependent color phenomenon. A comparison to spherical particles at similar size, Figure 7, shows that the dispersion color is not only dependent on particle size, but also on the particle shape. Similar results were also obtained by the Orendorff`s group [18]. Consequently, by engineering gold nanomaterials into different shapes, i.e., nanorod, nano-cage, or other anisotropic shapes, the SPR peak can be shifted from the visible light spectrum to nearly infrared regime, which can be used for many nanoparticle-mediated thermal therapies such as the plasmonic photothermal therapy (PPT) [19,20].


Ultrasonic-aided fabrication of gold nanofluids.

Chen HJ, Wen D - Nanoscale Res Lett (2011)

The colors of 90-nm gold nanoplates (left) and 90-nm GNPs (right).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211254&req=5

Figure 7: The colors of 90-nm gold nanoplates (left) and 90-nm GNPs (right).
Mentions: Different colors of gold nanofluids, shown in Figure 5, are due to the effect of surface plasmon resonance (SPR), an optical phenomenon arising from the collective oscillation of conduction electrons [18]. The SPR is a size-dependent phenomenon, which renders different colors for different gold nanofluids. For spherical nanoparticles, the color of gold dispersion is dark blue and purple-red for 15-nm and 90 nm particles, respectively. For gold nanoplates, Figure 5 also reveals a size-dependent color phenomenon. A comparison to spherical particles at similar size, Figure 7, shows that the dispersion color is not only dependent on particle size, but also on the particle shape. Similar results were also obtained by the Orendorff`s group [18]. Consequently, by engineering gold nanomaterials into different shapes, i.e., nanorod, nano-cage, or other anisotropic shapes, the SPR peak can be shifted from the visible light spectrum to nearly infrared regime, which can be used for many nanoparticle-mediated thermal therapies such as the plasmonic photothermal therapy (PPT) [19,20].

Bottom Line: The ultrasonication technique is found to be a very powerful tool in engineering the size and shape of GNPs.Subsequent property measurement shows that both particle size and particle shape play significant roles in determining the effective thermal conductivity.A large increase in effective thermal conductivity can be achieved (approximately 65%) for gold nanofluids using plate-shaped particles under low particle concentrations (i.e.764 μM/L).

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Engineering and Materials Science, Queen Mary University of London, London, UK. d.wen@qmul.ac.uk.

ABSTRACT
A novel ultrasonic-aided one-step method for the fabrication of gold nanofluids is proposed in this study. Both spherical- and plate-shaped gold nanoparticles (GNPs) in the size range of 10-300 nm are synthesized. Subsequent purification produces well-controlled nanofluids with known solid and liquid contents. The morphology and properties of the nanoparticle and nanofluids are characterized by transmission electron microscopy, scanning electron microscope, energy dispersive X-ray spectroscope, X-ray diffraction spectroscopy, and dynamic light scattering, as well as effective thermal conductivities. The ultrasonication technique is found to be a very powerful tool in engineering the size and shape of GNPs. Subsequent property measurement shows that both particle size and particle shape play significant roles in determining the effective thermal conductivity. A large increase in effective thermal conductivity can be achieved (approximately 65%) for gold nanofluids using plate-shaped particles under low particle concentrations (i.e.764 μM/L).

No MeSH data available.