Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 30: New Perspectives of Scattering at Soft Matter

CPP 30.6: Vortrag

Mittwoch, 28. März 2012, 16:30–16:45, C 264

Influence of the Incident Wavelength on the Apparent Diffusion Coefficient of Au Nano Rods — •Maryam Haghighi¹, Makus Plum¹, Georgios Gantzounis³, George Fytas^1,2, Hans-Jürgen Butt¹, and Werner Steffen¹ — ¹Max Planck Institute for Polymer Research, Mainz, Germany — ²Department of Material Science, University of Crete, Heraklion, Greece — ³University of Athens, Section of Solid State Physics, Athens, Greece

Depolarized dynamic light scattering is a powerful method to measure the diffusion and the rotation of anisotropic particles in solution [1]. Compared to free diffusion in bulk solution, movement close to an interface is influenced by several factors, e.g. hydrodynamic or electrostatic double layer forces. To investigate the dynamics of nanoparticles close to an interface Resonance Enhanced Dynamic Light Scattering (REDLS) is employed [2]. We investigate the diffusion as well as the rotation of Au nano rods in bulk and compared to experiments performed with REDLS close to the solid-liquid interface. Our results show an alteration of the apparent diffusion coefficient of the Au nano rods depending on the incident wavelengths and on the aspect ratio of Au nano rods in bulk solution. We attribute these non-intuitive results to the interplay of surface plasmons generated at certain wavelength in the nano rods themselves and the incident field for the light scattering experiment. [1] Berne, B.J. and Pecora, R., Dynamic light scattering with applications to chemistry Biology and physics (Dover, 2000) [2] Plum M. A., Steffen W., Fytas G., Knoll W. and Menges B., Optics Express 17:10364, 2009