Dresden 2011 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 37: Poster: Heterogeneous Nucleation and Microstructure Formation (related to SYMF)

CPP 37.2: Poster

Wednesday, March 16, 2011, 17:00–19:00, P2

Heterogeneous nucleation at a flat wall in a colloidal model system of charged spheres — •Andreas Engelbrecht, Rafaella Meneses, and Hans Joachim Schöpe — Staudingerweg 7, 55099 Mainz

The physical and chemical properties of solidified crystalline materials depend in a crucial way from the conditions of crystal nucleation. In order to improve the conditions of production processes and even to develop novel materials with extraordinary properties a detailed knowledge of the nucleation process is most desired.

We studied the kinetics of wall induced heterogeneous nucleation in colloidal model systems of charged spheres as function of undercooling determining nucleation rate densities, crystal growth velocities and the resulting micro structure. Applying classical concepts we extract key parameters of the nucleation process giving us the possibility to characterize the competition homogeneous and wall induced heterogeneous nucleation.

Classical theories of heterogeneous nucleation predict a reduction of the nucleation barrier height, which only depends on the contact angle of the crystal nucleus. We investigated the nucleation barrier height and its dependency on the undercooling in the system. Those results were compared with microscopic investigations of the contact angle.