Skin effect in adhesive solutions

Summary The membranometric method of quantitatively studying skin formation on surfaces of colloidal solutions developed byWo. Ostwald was adopted with slight modifications by the authors in their studies on adhesive solutions. The time of flow through a vertical capillary was found to vary with the time of contact and concentration, which may be attributed to any changes in viscosity during the period and formation of a skin. By running a control, the viscosity effect was eliminated. The position of the meniscus when sucked to a definite height and released, at different periods, is plotted as a function of time. It is suggested that the difference in the area between the curves for control and different periods of contact can be taken as a measure of the strength of skin formation. Results for gelatin solutions are given. With 2 figures in 3 details and 3 tables