Flow in Plateau Borders confined between vertical glass plates

H. RITACCO; W. DRENCKHAN; A. SAINT-JALMES; D. LANGEVIN; D. WEAIRE

Golm, Potsdam. Germany

Conferencia; EuFoam 2006: European Conference on Foams, emulsions and Applications; 2006

Max Planck Institute of Colloids and Interfaces

When one injects continuously some soapy solution between two vertical glass plates, one obtains two symmetric surface Plateau borders (having one face along a solid surface), separated by thin films.On the theoretical side, we studied how the flow and the Plateau border section depend on the injected flow rate, and on the interfacial viscoelastic properties (both in the regime of low flow rates where the two borders are separated by a thin film, and at high flowrates where they are merged into a single liquid bridge). Experimentally we have measured the Plateau border width as a function of the flow rate, for different surafactant solutions and different bulk viscosities. We also report results on the liquid flow inside the thin film separating the two borders.The comparison between experiments and predictions show some agreement, showing for instance that with this experimental setup and for usual low molecular weight surfactants, the interfaces can hardly sustain the bulk flow, and are submitted to strong interfacial shears. We then discuss about the possible connections between these results in isolated surface Plateau borders and 3D foam drainage issues, in order to find out  what can be elucidated from these studies. Finally, we also discuss about the possibility to use this setup to extract accurate interfacial shear viscosities; in that respect, estimatioons obtained from these experiments are compared to measurements made on sigle liquid interfaces by shear interfacial rheometers.