Direct calculation of interfacial tensions from computer simulation: Results for freely jointed tangent hard sphere chains

Abstract

We develop a methodology for the calculation of surface free energies based on the probability distribution of a wandering interface. Using a simple extension of the NpT sampling, we allow the interface area to randomly probe the available space and evaluate the surface free energy from histogram analysis and the corresponding average. The method is suitable for studying systems with either continuous or discontinuous potentials, as it does not require explicit evaluation of the virial. The proposed algorithm is compared with known results for the surface tension of Lennard--Jones and Square Well fluid, as well as for the interface tension of a bead--spring polymer model and good agreement is found. We also calculate interfacial tensions of freely jointed tangent hard sphere chains on athermal walls for a wide range of chain lengths and densities. The results are compared with three different theoretical approaches, Scaled Particle Theory, the Yu and Wu density functional theory and an analytical approximation based on the latter approach. Whereas SPT only yields qualitative results, the last two approaches are found to yield very good agreement with simulations.

20 pages, 6 figures, Phys. Rev. E in press,

References in corpus (9)

• An efficient, multiple range random walk algorithm to calculate the density of states
• Multicanonical Ensemble: A New Approach to Simulate First-order Phase Transitions
• Density functional theory for hard-sphere mixtures: the White-Bear version Mark II
• Morphological Thermodynamics of Fluids: Shape Dependence of Free Energies
• Evaluating the Surface Tension Using Grand Canonical Transition Matrix Monte Carlo and Finite-Size Scaling
• Molecular Dynamics Results on the Pressure Tensor of Polymer Films
• Hard-Sphere Fluids in Contact with Curved Substrates
• Short chains at solid surfaces: wetting transition from a density functional approach
• Phase transitions in nanosystems caused by interface motion: The Ising bi-pyramid with competing surface fields

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