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Quantitative Analysis of Attachment Time of Air Bubbles to Solid Surfaces in Water
journal contribution
posted on 2020-02-14, 21:49 authored by Seongsoo Han, Anh V. Nguyen, Kwanho Kim, Jai-koo Park, Kwangsuk YouThe
attachment of air bubbles to solid surfaces in water is encountered
in many natural processes and industrial applications. It has been
established that the attachment can occur between hydrophobic surfaces
and air bubbles. In this paper, we present novel experimental results
to quantify the attachment in terms of the attachment time. We show
that the attachment time can be determined from either the transient
force curve or the transient film thickness. These techniques for
determining the attachment time are based on the fact that the rupture
of a thin liquid film produces a large attachment force and a rapid
expansion of the three-phase contact radius in comparison with the
expansion of the film radius. The experimental results are quantitatively
analyzed using thin-film drainage theory and intermolecular forces,
which include the advanced multilayer van der Waals force and the
electrical double-layer force. The advanced van der Waals force theory
allows us to incorporate the effect of interfacial gas enrichment
(IGE) of dissolved gas in water at hydrophobic surfaces on the bubble-surface
attachment. Critically, if the presence of IGE is ignored, the experimental
results do not agree with the theory. Finally, IGE is shown to be
a significant factor in controlling hydrophobic attraction between
an air bubble and a hydrophobic surface and their attachment.