Regensburg 2013 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 45: Colloids and Complex Liquids II

CPP 45.7: Vortrag

Donnerstag, 14. März 2013, 17:00–17:15, H40

Gold Nano Rods Close to Charged and Uncharged Surfaces: Slowing Down of Rotational and Translational Diffusion — •Maryam Haghighi¹, Muhammad Nawaz Tahir², Wolfgang Tremel², Hans-Jürgen Butt¹, and Werner Steffen¹ — ¹Max Planck Institute for Polymer Research, P.O. Box 3148, 55128 Mainz, Germany — ²Institut für Anorganische Chemie und Analytische Chemie der Johannes Gutenberg-Universität, Duesbergweg 10-14, D-55099 Mainz, Germany

Diffusion and rotation of gold nanorods close to a solid interface were studied with two recently introduced techniques: Resonance Enhanced Dynamic Light Scattering (1) and Waveguide Enhanced Dynamic Light Scattering (2). We observed strong, plasmon-enhanced light scattering. Gold nano rods were stabilized by cetyltrimethylammonium bromide (CTAB). They showed an unexpected strong slowing down of the translational diffusion coefficient, whereas for rotational diffusion this slowing down is distinct but less pronounced. To find the possible influence of charges on the solid interface on this slowing we varyied the added salt concentration. Another approach was to cover the metal interface with an electrically neutral layer of poly-methylmethacrylate. A third approach was to completely exchange CTAB for its covalently bound, thiolated analogue 16-mercaptohexadecyl trimethylammonium bromide (MTAB), this reduces the slowing down considerably. (1) Plum MA, Menges B, Fytas G, Butt HJ, Steffen W, Rev. Sci Instr. 2011, 82, 015102 (2) Plum MA, Vianna SDB, Unger A, Roskamp RF, Butt HJ, Menges B, Steffen W, Soft Matter 2011, 7, 1501