Recommendations on determination of interfacial tension at the interface between two fluids by the spinning drop method

Abstract

There are studied popular methods of B. Vonnegut, H. Princen, J. Slattery, S. Torza for measuring the interfacial tension
at the interface between two immiscible fluids by the spinning drop method. There is provided the method for calculating the
geometric parameters of the spinning drop, and its results to the emergence of a spinning drop at the centre of the severely
cylindrical area that correspond to the range of the ratio of the cube of the drop`s length to its volume of 24–120, and the range of
the ratio of the spinning drop`s length to its diameter 4.00–0.35.
Based on the obtained calculation results there is offered the method for determining the interfacial tension by using
approximation dependence of the interfacial tension from the given drop volume, its length, difference in fluid densities and the
angular velocity of the drop rotation. There are assessed methodological errors of the offered and the known methods for
determining interfacial tension according to the rotating drop method. A flow chart and the overall appearance of the device that
implements the proposed method for measuring the interfacial tension is presented.