Dresden 2009 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Confined Fluids

CPP 17.7: Vortrag

Dienstag, 24. März 2009, 11:15–11:30, ZEU 160

Crystallization of soft crystals — •Max Wolff1, 2, 3, Andreas Magerl4, and Hartmut Zabel11Institute for Solid State Physics/EP IV, Ruhr-University Bochum, Germany. — 2Insitute Laue-Langevin, Grenoble, France. — 3Materials Physics, Uppsala University, Sweden. — 4Crystallography and Structural Physics, University Erlangen-Nürnberg, Erlangen, Germany

The crystallization of metals or ionic crystals either propagates throughout the melt starting from a single seed or small grains grow and develop simultaneously at different locations. In the first case, a single crystal is formed, and the second case results in a polycrystal, which may show pronounced texture. The driving force is the ionic or metallic interaction with binding energies on the order of 100 kBT at room temperature. Inert gas crystals form as a result of much weaker van der Waals forces, and regarding the spherical shape of atoms, in most cases an fcc structure. Soft matter is also characterized by relatively weak binding energies of hydrogen bonds, entropic forces, or hydrophobic interaction.

The crystallization of micelles formed by surfactant F127 solvated by 20 % in water was investigated in the vicinity of a hydrophilic interface. Upon entering the crystalline phase from low temperature, a large correlation length develops without preferential texture. Upon heating, the correlation length decreases and Oswald ripening is observed with crystallites orienting with respect to each other while retaining long-range and textured correlation [1].

[1] M. Wolff et al.: Langmuir (Letter) doi: 10.1021/la803015t.

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