Nanoscale fluid structure of liquid-solid-vapour contact lines for a wide range of contact angles

• Main Authors: Nold, Andreas, Sibley, David N, Goddard, Benjamin D, Kalliadasis, Serafim
• Format: Journal Article
• Language: English
• Published: 05-08-2017
• Subjects: Physics - Fluid Dynamics; Physics - Soft Condensed Matter
• DOI: 10.48550/arxiv.1503.03232

Mathematical Modelling of Natural Phenomena, 10(4), 111-125 (2015) We study the nanoscale behaviour of the density of a simple fluid in the
vicinity of an equilibrium contact line for a wide range of Young contact
angles between 40 and 135 degrees. Cuts of the density profile at various
positions along the contact line are presented, unravelling the apparent
step-wise increase of the film height profile observed in contour plots of the
density. The density profile is employed to compute the normal pressure acting
on the substrate along the contact line. We observe that for the full range of
contact angles, the maximal normal pressure cannot solely be predicted by the
curvature of the adsorption film height, but is instead softened -- likely by
the width of the liquid-vapour interface. Somewhat surprisingly however, the
adsorption film height profile can be predicted to a very good accuracy by the
Derjaguin-Frumkin disjoining pressure obtained from planar computations, as was
first shown in [Nold et al., Phys. Fluids, 26, 072001, 2014] for contact angles
less than 90 degrees, a result which here we show to be valid for the full
range of contact angles. This suggests that while two-dimensional effects
cannot be neglected for the computation of the normal pressure distribution
along the substrate, one-dimensional planar computations of the
Derjaguin-Frumkin disjoining pressure are sufficient to accurately predict the
adsorption height profile.