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CPP: Chemische Physik und Polymerphysik

CPP 17: Kolloidale Strukturen und Nanopartikel

CPP 17.2: Vortrag

Donnerstag, 14. März 2002, 10:00–10:20, H39

Dispersion of Noble Metal Nanoclusters in Bisphenol-(A)-polycarbonate by Acetone Vapor Sorption and Crystallization — •Kai Dolgner¹, Krzysztof Koziol¹, Vladimir Zaporojtchenko¹, Zhongyong Fan¹, Jörn Kanzow¹, Angelika Büttner¹, Franz Faupel¹, and Shigehito Deki² — ¹Lehrstuhl für Materialverbunde, Technische Fakultät der Universität Kiel, Kaiserstr. 2, 24143 Kiel, Germany — ²Department of Chemical Science and Engineering, Kobe University, Rokkodai-cho, Nado-ku, Kobe 657-8501, Japan

If noble metal (e.g. copper or gold) is evaporated onto amorphous bisphenol-(A)-polycarbonate the polymer surface will be covered by nanocluster and not by a continuous initially metal layer. These clusters can be dispersed into the bulk by acetone vapor induced crystallization of the polymer. The embedding and dispersion of gold was analyzed with depth profiling X-ray photoelectron spectroscopy, transmission electron microscopy, and atomic force microscopy. The time scale for sorption and crystallization were determined by mass-uptake and absorption measurements. We will present a tentative model of the dispersion process. The penetrating organic vapor provides the long-range mobility to the polymer chains, which now can rearrange into the energetically preferred crystalline state. Initially the cluster are embedded by the lowering of the surface Gibbs free energy, later the crystallization appears to provide the mobility for the dispersion process. There are indications that this could be attributed to the stress occurring during the crystallization process.