title: Competition between heterogeneous and homogeneous nucleation near a flat wall.
abstract: We studied the competition between heterogeneous and homogeneous nucleation of an aqueous suspension of charged colloidal spheres close to the container walls. Samples of equilibrium crystalline structure were shear-melted and the metastable melt left to solidify after the cessation of shear. The crystallization kinetics was monitored using time-resolved scattering techniques: at low particle number densities n we applied an improved static light scattering method while at large particle concentrations ultra-small-angle x-ray scattering was applied for the first time. Our results show some unexpected behavior: the heterogeneous nucleation at the container walls is delayed in comparison to the homogeneous bulk nucleation and its rate density appears surprisingly slightly smaller, demonstrating the complexity of the observed crystallization process.
authors.affiliation: Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), D-51170 Köln, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Wette
authors.forename: Andreas
authors.initials: A
authors.lastname: Engelbrecht
authors.forename: Roushdey
authors.initials: R
authors.lastname: Salh
authors.forename: Ina
authors.initials: I
authors.lastname: Klassen
authors.forename: Dirk
authors.initials: D
authors.lastname: Menke
authors.forename: Dieter M
authors.initials: DM
authors.lastname: Herlach
authors.forename: Stephan V
authors.initials: SV
authors.lastname: Roth
authors.forename: Hans Joachim
authors.initials: HJ
authors.lastname: Schöpe