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DY: Fachverband Dynamik und Statistische Physik
DY 5: Colloids and Complex Fluids II (joint session CPP/BP/DY)
DY 5.7: Vortrag
Montag, 7. März 2016, 11:15–11:30, H51
Crystal nucleation in metastable hard sphere fluids by confocal microscopy — Achim Lederer1 and •Hans Joachim Schöpe2 — 1Retsch Technology GmbH, Retsch-Allee 1-5, 42781 Haan, Germany — 2Eberhards Karls Universität Tübingen, Auf der Morgenstelle 10, 72026 Tübingen, Germany
Crystal nucleation in colloidal hard spheres is a longstanding research topic. Light scattering and confocal microscopy as well as simulations had been carried out to characterize the nucleation process and to get a microscopic picture. In these studies results both differ and agree with each other. It is still unclear whether the large disagreement in the nucleation rate densities between the light scattering experiments and simulations are of physical nature or result from differing data analyses. Furthermore, the temporal evolution of the microscopic structure has not yet been characterized sufficiently. Using laser-scanning confocal microscopy we study crystal nucleation in colloidal hard spheres. The used system has been characterized with extreme care to allow for meaningful comparison with other experiments and simulations. Observing a large sample volume we can analyze the nucleation process with high accuracy. This allows us to obtain meaningful data of the nucleation rate density, critical nucleus size and nucleation barrier. Furthermore, we determine the time-dependent interfacial tension through how the cluster size distribution evolves. Analyzing the nucleation process on a microscopic scale, we confirm the scenario of precursor-mediated crystal nucleation. In addition we show in great detail the structure evolution from precursor to crystal.