Measurement of the film tension of foam films in dynamic conditions

The method for direct measurement of the film tension of foam films has been developed with a view to measuring the film tension in dynamic conditions. The new method allows the determination of the dynamic film tension when the curvature radius, the contact line radius, and the area of the film increase or decrease with very different rates. Measurements with Newton black films from sodium dodecyl sulphate aqueous solution have been performed. The results show that in a wide range of variation rates of the film geometrical parameters the film tension remains constant.