Flow dichroism as a reliable method to measure the hydrodynamic aspect ratio of gold nanoparticles

Reddy, N.K.; Pastoriza-Santos, I.; Dhont, J.K.G.; Liz-Marzan, L.; Vermant, J.; Lang, P.R.; Pérez-Juste, J.

doi:10.1021/nn201033x

Journal Article

Flow dichroism as a reliable method to measure the hydrodynamic aspect ratio of gold nanoparticles

Reddy, N. K. ; Pérez-Juste, J. ; Pastoriza-Santos, I. ; Lang, P. R.FZJ* ; Dhont, J. K. G.FZJ* ; Liz-Marzan, L. ; Vermant, J.

2011
Soc. Washington, DC

ACS Nano, 2011, 5 (6), 4935 – 4944 ACS nano 5, 4935 - 4944 (2011) [10.1021/nn201033x]

This record in other databases:

Please use a persistent id in citations: http://hdl.handle.net/2128/4416 doi:10.1021/nn201033x

Abstract: Particle shape plays an important role in controlling the optical, magnetic, and mechanical properties of nanoparticle suspensions as well as nanocomposites. However, characterizing the size, shape, and the associated polydispersity of nanoparticles is not straightforward. Electron microscopy provides an accurate measurement of the geometric properties, but sample preparation can be laborious, and to obtain statistically relevant data many particles need to be analyzed separately. Moreover, when the particles are suspended in a fluid, it is important to measure their hydrodynamic properties, as they determine aspects such as diffusion and the rheological behavior of suspensions. Methods that evaluate the dynamics of nanoparticles such as light scattering and rheo-optical methods accurately provide these hydrodynamic properties, but do necessitate a sufficient optical response. In the present work, three different methods for characterizing nonspherical gold nanoparticles are critically compared, especially taking into account the complex optical response of these particles. The different methods are evaluated in terms of their versatility to asses size, shape, and polydispersity. Among these, the rheo-optical technique is shown to be the most reliable method to obtain hydrodynamic aspect ratio and polydispersity for nonspherical gold nanoparticles for two reasons. First, the use of the evolution of the orientation angle makes effects of polydispersity less important. Second, the use of an external flow field gives a mathematically more robust relation between particle motion and aspect ratio, especially for particles with relatively small aspect ratios.

Keyword(s): Gold: chemistry (MeSH) ; Hydrodynamics (MeSH) ; Light (MeSH) ; Metal Nanoparticles: chemistry (MeSH) ; Microscopy, Electron: methods (MeSH) ; Microscopy, Electron, Transmission: methods (MeSH) ; Models, Statistical (MeSH) ; Nanoparticles (MeSH) ; Nanotechnology: methods (MeSH) ; Optics and Photonics (MeSH) ; Particle Size (MeSH) ; Rheology: methods (MeSH) ; Scattering, Radiation (MeSH) ; Gold ; J ; transmission electron microscopy ; Brownian motion ; Jeffery orbits ; depolarized dynamic light scattering ; gold rod (auto) ; gold decahedron (auto) ; transmission electron microscopy (auto) ; depolarized dynamic light scattering (auto) ; Brownian motion (auto) ; flow dichroism (auto) ; Jeffery orbits (auto)

Classification:

Note: The authors thank Dr. P. Holmqvist for useful discussions. We thank the EU for funding through the project NANODIRECT (Grant No. CP-FP 213948-2).; Record converted from JUWEL: 18.07.2013

Contributing Institute(s):