Observations on Deformation of Drops in Polymer Solutions

Abstract

Observations have been performed of liquid drops suspended in several chain polymer solutions with respect to their small deformation individually.Two flow systems have been set up in which the drops or bubbles are subject to streaming with pure shear and to uniform streaming at low constant speed. In the first case, the theoretical formula derived by Taylor is compared with the experimental results, which show that though the deformation is always linear with the applied shear, both larger and smaller deformations than those expected theoretically take place. It has become evident that there are other important factors than the shear rate, interfacial tension and viscosity, i. e. concentration of the solution, C, and the degree of polymerization of the solution, n for the same kind of liquid system. The diagrams of the dimensionless deformation vs. shear rate indicate that they contribute to the drop deformation in the form Cn.For the second case of uniform streaming, gas bubbles deform into various shapes. Qualitative interpretation of the shape is also possible in terms of Cn.