Our Spinning Drop Tensiometer – SDT measures interfacial tension with a high degree of accuracy and a particularly wide measuring range. The SDT is the ideal solution for the quality control and development of emulsions and surfactants thanks to its enormous bandwidth, small sample volumes and simple handling during preparation. Exact capture of extremely low interfacial tensions also makes the SDT an instrument particularly well-suited for analyzing the interfacial behavior of mini emulsions and micro emulsions, for example for tertiary oil recovery or the pharmaceutical branch.
Exact rotation, image evaluation and drop positioning
With the spinning drop method, measuring of the interfacial tension is carried out by analyzing the video image of a drop surrounded by fluid in a rotating capillary.The accuracy of the video analysis and the rotational speed are decisive for the precision of the spinning drop method. That is why a high-resolution USB3 camera and an exactly controlled precision motor with excellent speed constancy are among the most important components of the SDT, combined with the intelligent and robust image evaluation algorithms of the software ADVANCE. In order to make observing a running measurement obsolete, the drop can be kept in the center of the video image automatically using the Drop Positioning function of ADVANCE.
In addition to the standard Vonnegut method, the ADVANCE software’s spectrum of methods also encompasses an evaluation of the drop shape in accordance with Young-Laplace. This makes it possible to work at a slower rotational speed and so expands the range of the instrument allowing easy measurement of high interfacial tensions. A further advantage of this method lies in its robustness.