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.