TY  - JOUR
AU  - Reddy, N.K.
AU  - Pérez-Juste, J.
AU  - Pastoriza-Santos, I.
AU  - Lang, P.R.
AU  - Dhont, J.K.G.
AU  - Liz-Marzan, L.
AU  - Vermant, J.
TI  - Flow dichroism as a reliable method to measure the hydrodynamic aspect ratio of gold nanoparticles
JO  - ACS nano
VL  - 5
SN  - 1936-0851
CY  - Washington, DC
PB  - Soc.
M1  - PreJuSER-16099
SP  - 4935 - 4944
PY  - 2011
N1  - 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).
AB  - 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.
KW  - Gold: chemistry
KW  - Hydrodynamics
KW  - Light
KW  - Metal Nanoparticles: chemistry
KW  - Microscopy, Electron: methods
KW  - Microscopy, Electron, Transmission: methods
KW  - Models, Statistical
KW  - Nanoparticles
KW  - Nanotechnology: methods
KW  - Optics and Photonics
KW  - Particle Size
KW  - Rheology: methods
KW  - Scattering, Radiation
KW  - Gold (NLM Chemicals)
KW  - J (WoSType)
KW  - transmission electron microscopy
KW  - Brownian motion
KW  - Jeffery orbits
KW  - depolarized dynamic light scattering
LB  - PUB:(DE-HGF)16
C6  - pmid:21545088
UR  - <Go to ISI:>//WOS:000292055200079
DO  - DOI:10.1021/nn201033x
UR  - https://juser.fz-juelich.de/record/16099
ER  -