Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 20: POSTERS Driven Soft Matter
CPP 20.21: Poster
Mittwoch, 27. Februar 2008, 16:00–18:30, Poster A
Crystallizing hard spheres — •Sara Iacopini1, Hans Joachim Schöpe1, Eckhard Bartsch2, and Thomas Palberg1 — 1Johannes Gutenberg Universität, Institut für Physik, Staudingerweg 7, D-55128 Mainz, Germany — 2Albert Ludwigs Universität, Institut für Physikalische Chemie, Albertstraße 21, D-79104 Freiburg, Germany
Colloidal systems display phase transition that are totally analogous to those observed in atomic systems. In particular, a system of colloidal particles where only excluded volume interactions are relevant (a hard-spheres system) tends to form an ordered crystal phase upon increasing the particles volume fraction. Beyond the freezing line, the undercooling of the system acts as a driving force towards the formation of the solid phase. However, it is still a matter of theoretical and experimental investigations which path will the system actually follow in its journey towards the thermodynamically stable state, and which factors may influence it. We studied by means of light scattering the crystallization kinetics of polystyrene microgel colloids in an organic solvent, a system that has proved to display hard-sphere-like behaviour. Our experiments allowed for monitoring the phase transition from the metastable fluid, to the onset of nucleation and growth of the crystallites, up to the later stage of ripening of the polycrystalline material. We investigate how, with increasing particles volume fraction, the growing competition between the thermodynamic driving force and the approaching dynamical arrest modifies the crystallization scenario.