Marjolein Dijkstra — Page 2

PubMed2002

Entropic wetting and many-body induced layering in a model colloid-polymer mixture.

We develop an efficient simulation scheme to study a model suspension of equally sized colloidal hard spheres and nonadsorbing ideal polymer coils, both in bulk and adsorbed against a planar hard wall. The many-body character of the polymer-mediated effective interactions between the colloids yields a bulk phase diagram and adsorption phenomena that differ substantially from those found for pairwise simple fluids; e.g., we find an anomalously large bulk liquid regime and, far from the bulk triple point, three layering transitions in the partial wetting regime prior to a transition to complete wetting by colloidal liquid.

Journal Article↗

PubMed2002

Phase behavior of hard spheres with a short-range Yukawa attraction.

The phase diagram of a system consisting of hard spheres with an attractive Yukawa interaction is computed by Monte Carlo simulations. Upon decreasing the range of attraction, we find the following scenarios: (a) a stable fluid-fluid and fluid-solid transition, a triple point with fluid-fluid-solid coexistence, and a metastable isostructural solid-solid transition (b) a fluid-fluid and isostructural solid-solid transition, which are both metastable with respect to a broad fluid-solid transition, (c) a metastable fluid-fluid transition, a stable isostructural solid-solid and fluid-solid transition and a triple point with fluid-solid-solid coexistence. Our results show that a large part of the fluid-solid coexistence region is occupied by metastable fluid-fluid and/or solid-solid coexistence regions, which has repercussions on the kinetics and on the nonequilibrium behavior of the system, such as nucleation, vitrification, and gelation.

Journal Article↗