Regensburg 2010 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 17: Anomalous Transport I (joint BP, DY)

BP 17.5: Vortrag

Mittwoch, 24. März 2010, 10:30–10:45, H38

Localization and glass formation of colloids confined in porous media — •Jan Kurzidim, Daniele Coslovich, and Gerhard Kahl — Institut für Theoretische Physik and Center for Computational Materials Science, Technische Universität Wien, Wiedner Hauptstraße 8-10, A-1040 Wien, Austria

Using molecular dynamics simulations we study the slow dynamics of a hard-sphere fluid confined in a matrix quenched from an equilibrated hard-sphere fluid [Kurzidim et al., PRL 103, 138303 (2009)], resembling the movement of hard colloids in porous environments. We observed the presence of both discontinuous and continuous glass transitions, anomalous diffusion, and a de-coupling of the time scales for the relaxation of the single-particle and the collective correlators. Our observations are consistent with many predictions of a recent extension of mode-coupling theory for so-called “quenched-annealed” systems. Notably, however, we found no evidence of the re-entrant regime in the kinetic diagram predicted by the theory. To provide a deeper insight into the microscopic details of the underlying processes, we calculated the quantities of interest separately for particles trapped in voids formed by the matrix and for particles that unrestrictedly move through the entire system. In order to evaluate the degree of universality of the observed phenomena, we extended our investigation to model colloids with soft interactions, employing both numerical solutions of the equations of the theory, and molecular dynamics simulations.