Dresden 2003 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

CPP: Chemische Physik und Polymerphysik

CPP 2: Colloide, Nanopartikel und Kapseln

CPP 2.11: Vortrag

Montag, 24. März 2003, 12:45–13:00, ZEU/260

Self-Assembly of CoPt₃ Nanoparticle Rings in Thin Polymer Films — •Leonid Govor¹, Elena Shevchenko², Gottfried H. Bauer¹, and Jürgen Parisi¹ — ¹University of Oldenburg, Faculty of Physics, Department of Energy and Semiconductor Research, Department of Semiconductor Physics and Radiation Conversion — ²Institute of Physical Chemistry, University of Hamburg

Ferromagnetic CoPt₃ nanoparticles (with 6 nm diameter) self-assemble into micrometer-sized rings in a thin polymer film (4 nm thickness). The polymer films with nanoparticles were prepared from a binary blend containing 1% nitrocellulose solution in amyl acetate and a CoPt₃ nanocrystal solution in hexane (with hexadecylamine (HDA) as stabilizing agent) with a concentration of 24 mg/ml. For the formation of thin films we used the wetting of the binary solution on water surface. As a result of wetting and of evaporation of the solvent, regular patterns of HDA droplets can be found on the cellulose thin film. The CoPt₃ nanoparticles form rings at the edges of the HDA droplets. Droplet heights h_d depend on droplet diameters D_d as h_d ∼ D_d^0.86. The distance between the droplets d_d changes with the diameter as d_d ∼ D_d^1.14. The number of droplets N_d per surface area depends on the HDA film thickness h_f as N_d ∼ h_f^−3.46. The experimental results are compared with theoretical predictions.