Regensburg 2019 – wissenschaftliches Programm
CPP 25.5: Poster
Dienstag, 2. April 2019, 14:00–16:00, Poster B1
1D capillary collapse and the role of initial fluctuations in Brownian Dynamics and DDFT — •Anja Schreiber, Johannes Bleibel, and Martin Oettel — Institut für angewandte Physik, Universität Tübingen, Tübingen, Germany
We investigate the so–called capillary collapse of colloidal particles trapped a fluid interface in 1D Brownian Dynamics (BD) simulations. Interfacially trapped, micrometer–sized colloidal particles interact via long–ranged capillary attraction. The interaction is formally analogous to screened Newtonian gravity with the capillary length λ as the tuneable screening length. Within intensive studies of the dynamics in 2D, it turned out that radially averaged Dynamical Density Functional Theory (DDFT) only captures the dynamics at initial times and largely deviates from simulation results later on. This discrepancy has been traced to the role of an initially averaged configuration in DDFT. In BD, simulation runs are averaged over initial conditions and noise. The long–ranged potential and initial density fluctuations allow for an early clustering of particles prior to a global, collective collapse similar to a self gravitating fluid. This clustering remains present through most stages of the evolution and renders averaged density profiles, which deviate largely from DDFT. Since the clustering process is much more restricted in 1D, we use 1D simulations in order to shed light on the precise role of initial fluctuations in the averaging process and subsequent dynamics both in BD simulations and DDFT.
 Bleibel, Domínguez, Oettel, Dietrich, Soft Matter 10, 4091 (2014).
 Bleibel, Domínguez, Oettel, JPCM 28, 244021 (2016).