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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.42: Poster

Donnerstag, 27. März 2003, 15:30–18:00, P1

Solidification of model charged colloidal spheres — •Patrick Wette, Hans Joachim Schöpe, Jianing Liu, and Thomas Palberg — Institut für Physik Universität Mainz , Staudingerweg 7, 55099 Mainz

We report on the solidification kinetics of deionised aqueous suspensions of charged latex spheres in dependence on the particle density n. Growth velocities were measured by microscopy, nucleation rate densities obtained from average crystallite sizes determined with static light scattering. A quantitative estimate of the chemical potential difference between melt and solid is derived from the growth data and used for interpretation of nucleation data in terms of classical nucleation theory. Using long time self-diffusion coefficient at freezing to approximate the kinetic pre-factor of homogeneous nucleation, we find the surface tensions per squared inter-particle distance to increase roughly linearly from 2.5kT to 4.4kT as n is increased from 20µ m⁻³ to 65µ m⁻³ . This result is qualitatively robust against changes in the approximation for the pre-factor and is qualitatively understood in terms of an increased surface density of the nucleus and an increased particle interaction.