Article ID Journal Published Year Pages File Type
594845 Colloids and Surfaces A: Physicochemical and Engineering Aspects 2011 5 Pages PDF
Abstract

Determination of thinning rates of free liquid films is important for many applications involving formation and stability of foams. One of examples is self-foaming of polymer melts. The morphology of the resulting foam is governed by the thinning rates of interbubble films and by the thinning rates of free films separating the bubbles from the ambient gas. The film thinning dynamics depends on the rheological properties of the liquid. In this theoretical and numerical work a model describing the thinning of a free liquid film is developed for viscoelastic liquids. The upper-convected Maxwell model is used for the description of liquid rheology. We apply an asymptotic analysis to derive the equations governing thin film evolution. The evolution equation is solved for the lamellar region and for the region of transition between the thinning lamella and the Plateau border. The effect of the relaxation time on the film profile and its evolution is quantified. We find out that the film thinning rate increases with increasing relaxation time.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We model the thinning of a free liquid film of a viscoelastic liquid. ► Upper-convective Maxwell model is used for the description of liquid rheology. ► Film thinning rate increases with increasing relaxation time. ► The dependence of the film thinning rate on the interface curvature at the Plateau border is stronger for viscoelastic liquids in comparison with the Newtonian liquids.

Related Topics
Physical Sciences and Engineering Chemical Engineering Colloid and Surface Chemistry
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