Berlin 2005 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 22: Colloids

CPP 22.5: Vortrag

Dienstag, 8. März 2005, 12:15–12:30, TU C243

Effective capillary interaction of colloidal particles at fluid interfaces — •Martin Oettel¹, Alvaro Dominguez^1,2, and Siegfried Dietrich¹ — ¹Max–Planck–Institut für Metallforschung, Heisenbergstr. 3, D–70569 Stuttgart, Germany — ²Fisica Teorica, Dept. FAMN, Apartado 1065, E-41080 Sevilla, Spain

We present an analysis of the effective force between two smooth spherical colloids floating at a fluid interface due to deformations of the interface. The results hold in general and are applicable independently of the source of the deformation provided the capillary deformations are small so that a superposition approximation for the deformations is valid. We conclude that an effective long–ranged attraction is possible if the net force on the system does not vanish. Otherwise, the interaction is short–ranged and cannot be computed reliably based on the superposition approximation. As an application, we consider the case of like–charged, smooth nanoparticles and electrostatically induced capillary deformation. The resulting long–ranged capillary attraction can be easily tuned by a relatively small external electrostatic field, but it cannot explain recent experimental observations of attraction if these experimental systems were indeed isolated.
M. Oettel, A. Dominguez and S. Dietrich, cond-mat/0411329.