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Louisiana State University

Disjoining pressure

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Full-Text Articles in Mechanical Engineering

Theory Of Curvature-Dependent Disjoining Pressure And Its Application To Liquid Films, Jin Zhang Jan 2006

Theory Of Curvature-Dependent Disjoining Pressure And Its Application To Liquid Films, Jin Zhang

LSU Doctoral Dissertations

A liquid film of thickness h < 100 nm is subject to additional intermolecular forces, which are collectively called disjoining pressure Pi. Since Pi dominates at small film thicknesses, it determines the stability and wettability of thin films. Current theory for uniform films gives Pi = Pi(h). It becomes unbounded as h -> 0. We present a theory of curvature-dependent disjoining pressure. The new Pi depends on the curvature hxx, slope hx, and h. When this theory is implemented for Lennard-Jones liquid films, the new Pi is bounded as h -> 0. We show that this Pi captures three regimes of drop behavior (complete wetting, partial wetting, and pseudo partial wetting) without altering the signs of the long and short-range interactions. We also find that a drop with a uniform film is linearly stable, whereas a drop without a uniform film is unstable. Evaporating thin films is …


A Slope-Dependent Disjoining Pressure For Lennard-Jones Liquid Films, Taeil Yi Jan 2005

A Slope-Dependent Disjoining Pressure For Lennard-Jones Liquid Films, Taeil Yi

LSU Master's Theses

A molecule in a bulk liquid is subject to intermolecular forces. A molecule in a thin liquid film may experience additional intermolecular forces, if the thin film thickness h is less than roughly 100 nm. The additional forces arise from the molecule's proximity to different materials or phases sandwiching the thin film. The effect of these intermolecular forces at the continuum level is captured by disjoining pressure &Pi. Since dominates at small film thickness, it determines the stability and wettability of thin films. To leading order, Π = Π (h) because thin films are generally uniform. This form, however, can …


A Disjoining Pressure For Small Contact Angles And Its Applications, Qingfang Wu Jan 2003

A Disjoining Pressure For Small Contact Angles And Its Applications, Qingfang Wu

LSU Master's Theses

A thin liquid film experiences additional intermolecular forces when the film thickness h is less than roughly 100 nm. The effect of these intermolecular forces at the continuum level is captured by the disjoining pressure . Since dominates at small film thicknesses, it determines the stability and wettability of thin films. To leading order, a thin film can be treated as uniform and . This form, however, cannot be applied to films with non-zero contact angles. A recent ad-hoc derivation to include the slope leads to a that allows a contact line to move without slip. This work derives a …