Techniques for Studying Structural Parameters of Foams

The polyhedral foam consists of polyhedral gas bubbles, the faces of which are flat or lightly bent liquid films, while the edges are the plateau borders and the edge cross points are the vortexes. Several techniques can be applied to obtain the analytical dependence of these characteristics and the structural parameters of the foam [4]. 

The foam expansion ratio can be characterised by the liquid volume fraction in the foam, which is the sum of the volume fractions of the films, plateau borders and vertexes. Alternatively, one can use the foam density as a measure of the foam expansion ratio. The reduced pressure in the foam plateau border can be measured using a capillary manometer [4]. The bubble size and shape distribution in a foam can be determined by microphotography of the foam. Information about the liquid distribution between films and plateau borders is obtained from the data on the border radius of curvature, the film thickness and the film to plateau border number ratio obtained in an elementary foam cell. 

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