A fundamental measure density functional for fluid and crystal phases of the Asakura-Oosawa model

作者：Mortazavifar Mostafa; Oettel Martin

来源：Journal of Physics: Condensed Matter , 2016, 28(24): 244018.

DOI：10.1088/0953-8984/28/24/244018

• classical density functional theory
• fundamental measure theory
• colloid-polymer mixtures
• depletion interaction
• crystallization and nucleation

We investigate a density functional for the Asakura-Oosawa model of colloid-polymer mixtures, describing both fluid and crystal phases. It is derived by linearizing the two-component fundamental-measure hard sphere tensor functional in the second (polymer) component. We discuss the formulation of an effective density functional for colloids only. For small polymer-colloid size ratios the effective, polymer-induced potential between colloids is short-range attractive and of two-body form but we show that the effective density functional is not equivalent to standard mean-field approaches where attractions are taken into account by terms second order in the colloid density. We calculate numerically free energies and phase diagrams in good agreement with available simulations, furthermore we discuss the colloid and polymer distributions in the crystal and determine equilibrium vacancy concentrations. Numerical results reveal a fairly strong sensitivity to the specific type of underlying fundamental measure hard sphere functional which could aid further development of fundamental measure theory.

• 出版日期2016-6-22