Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 29: Crystallisation, Nucleation and Self assembly

CPP 29.5: Vortrag

Mittwoch, 28. März 2012, 16:30–16:45, C 243

Homogeneous and flat wall heterogeneous nucleation in colloids with various interaction — Andreas Engelbrecht, Markus Franke, Achim Lederer, Sara Iacopini, Richard Beyer Beyer, and •Hans Joachim Schöpe — Johannes Gutenberg-Universität Mainz, Institut für Physik, Staudinger Weg 7, 55099 Mainz, Deutschland

Understanding crystal nucleation and growth is of great interest in condensed matter physics and material science. Especially at low metastabilities crystal nucleation is dominated by heterogeneous nucleation on container walls or impurities and the competition between wall and bulk crystallization determines the microstructure of the polycrstal. Notwithstanding its relevance heterogeneous nucleation is not well understood. One promising approach to the problem is offered by the study of colloidal suspensions. In colloids the particle interactions can be experimentally adjusted to include short (hard spheres, HS) and long ranged (charged spheres, CS) repulsions as well as attractions originated by entropic forces (attractive spheres, AS). We studied the kinetics of homogeneous and wall induced heterogeneous nucleation in different colloidal model systems with various interaction (CS, HS, AS) as function of super saturation. Using light scattering as well as microscopy techniques a comprehensive analysis of the crystallization process was obtained. We can show that the competition of wall and bulk crystallization is altered significantly with the nature of the particle interaction.