Fluid structure in the immediate vicinity of an equilibrium three-phase contact line and assessment of disjoining pressure models using density functional theory

• Main Authors: Nold, Andreas, Sibley, David N, Goddard, Benjamin D, Kalliadasis, Serafim
• Format: Journal Article
• Language: English
• Published: 04-08-2014
• Subjects: Physics - Fluid Dynamics; Physics - Soft Condensed Matter; Physics - Statistical Mechanics
• DOI: 10.48550/arxiv.1406.5465

Phys. Fluids 26, 072001 (2014) We examine the nanoscale behavior of an equilibrium three-phase contact line
in the presence of long-ranged intermolecular forces by employing a statistical
mechanics of fluids approach, namely density functional theory (DFT) together
with fundamental measure theory (FMT). This enables us to evaluate the
predictive quality of effective Hamiltonian models in the vicinity of the
contact line. In particular, we compare the results for mean field effective
Hamiltonians with disjoining pressures defined through (I) the adsorption
isotherm for a planar liquid film, and (II) the normal force balance at the
contact line. We find that the height profile obtained using (I) shows good
agreement with the adsorption film thickness of the DFT-FMT equilibrium density
profile in terms of maximal curvature and the behavior at large film heights.
In contrast, we observe that while the height profile obtained by using (II)
satisfies basic sum rules, it shows little agreement with the adsorption film
thickness of the DFT results. The results are verified for contact angles of
20, 40 and 60 degrees.