Berlin 2015 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 45: P10: Colloids and Complex Liquids

CPP 45.4: Poster

Wednesday, March 18, 2015, 10:00–13:00, Poster A

Density functional theory for the bulk phases of a colloid-polymer mixture — •Mostafa Mortazavifar and Martin Oettel — Institut für Angewandte Physik, Uni Tübingen, Tübingen, Germany

We propose to treat gas, liquid, and crystal phases of the Asakura-Oosawa model (AO) for a colloid-polymer mixture within the framework of Fundamental Measure Theory. In AO model the polymers are an ideal gas, but colloid-colloid and colloid-polymer interactions are of hard sphere type. A new expression is derived for the excess part of the free energy. The bulk free energy and liquid-gas transition are calculated for various values of polymer reservoir packing fraction, η_p^r, and colloid-polymer size ratios, q=2R_g/σ; σ is the diameter of colloid particles and R_g is the gyration radius of polymers. By a self consistent full minimization scheme the free energy of the fcc solid and the solid-liquid phase transition is calculated for different values of q and η_p^r. In the limit of η_p^r to zero, the problem reduces to the pure hard sphere case. By increasing the reservoir packing fraction of polymers, the fluid-solid coexistence region broadens compared to pure hard spheres.