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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 12: Poster: Colloids and Complex Fluids

CPP 12.6: Poster

Montag, 7. März 2016, 18:15–21:00, Poster B2

Colloids trapped at fluid interfaces: Capillary-driven dynamics for binary mixtures — •Malte Lütje, Martin Oettel, and Johannes Bleibel — Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen

We investigate a binary system of micron-sized colloids that are trapped at liquid-liquid or liquid-gas interfaces. The deformation of the interface due to external forces (i.e. gravity) acting on the colloids gives rise to long-ranged, logarithmic capillary attractions. For a wide range of parameters, these attractions render the system unstable: An initially homogeneous distribution of the colloids on the surface will collapse.

We perform Brownian Dynamics simulations of this system. Interactions between colloidal particles are implemented through a short-ranged repulsion and capillary interactions which dominate the dynamics on different length scales, respectively. We study the dynamical properties and conditions for stability.

As the capillary interactions strongly depend on the radius of the particles, the system and its dynamical phase diagram change if we introduce a second species of smaller colloids. We study the impact of the second species on stability and provide simulation results for the capillary collapse using various sets of parameters.