Berlin 2012 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Poster: Crystallisation, Nucleation and Self assembly

CPP 17.13: Poster

Dienstag, 27. März 2012, 18:15–20:15, Poster A

Manipulating crystallization by seed induced heterogeneous nucleation — •Andreas Engelbrecht and Hans Joachim Schöpe — Johannes Gutenberg-Universität, Mainz, Germany

Most solids consist of crystals and their material properties are highly controlled by the crystallization kinetics. Controlling crystal nucleation and growth is of great interest in condensed matter physics and material science. Container walls and impurities are almost omnipresent making heterogeneous nucleation the dominant process in many cases biasing the material microstructure. We here present a crystallization kinetics study in a colloidal model system of charged spheres adding nucleation seeds analog to inoculation in metallic systems.

We performed video microscopy of the crystallization process observing nucleation and growth of both homogeneously nucleated and seed induced crystals. While single crystals form by homogeneous nucleation, multi domain crystals nucleate on seeds appearing like bloomy flowers. We are able to extract time resolved nucleation rate densities, crystal size distributions and induction times for different seed concentrations. We see homogeneously nucleated crystals compete with those induced by the seeds. Hence crystallization kinetics and therefore also the arising microstructure can be tuned with the amount of added seeds.