Wetting on a spherical wall: influence of liquid-gas interfacial propertiesReport as inadecuate



 Wetting on a spherical wall: influence of liquid-gas interfacial properties


Wetting on a spherical wall: influence of liquid-gas interfacial properties - Download this document for free, or read online. Document in PDF available to download.

Download or read this book online for free in PDF: Wetting on a spherical wall: influence of liquid-gas interfacial properties
We study the equilibrium of a liquid film on an attractive spherical substrate for an intermolecular interaction model exhibiting both fluid-fluid and fluid-wall long-range forces. We first reexamine the wetting properties of the model in the zero-curvature limit, i.e., for a planar wall, using an effective interfacial Hamiltonian approach in the framework of the well known sharp-kink approximation SKA. We obtain very good agreement with a mean-field density functional theory DFT, fully justifying the use of SKA in this limit. We then turn our attention to substrates of finite curvature and appropriately modify the so-called soft-interface approximation SIA originally formulated by Napi\orkowski and Dietrich Phys. Rev. B 34, 6469 1986 for critical wetting on a planar wall. A detailed asymptotic analysis of SIA confirms the SKA functional form for the film growth. However, it turns out that the agreement between SKA and our DFT is only qualitative. We then show that the quantitative discrepancy between the two is due to the overestimation of the liquid-gas surface tension within SKA. On the other hand, by relaxing the assumption of a sharp interface, with, e.g., a simple smoothing of the density profile there, markedly improves the predictive capability of the theory, making it quantitative and showing that the liquid-gas surface tension plays a crucial role when describing wetting on a curved substrate. In addition, we show that in contrast to SKA, SIA predicts the expected mean-field critical exponent of the liquid-gas surface tension.



Author: Andreas Nold; Alexandr Malijevsk√Ĺ; Serafim Kalliadasis

Source: https://archive.org/







Related documents