Thanks to a grant by the country Mecklenburg-Western-Pomerania provided by the European Fund for Regional Development (EFRE) we were able to procure and install a spinning drop tensiometer in 2015.
With this instrument our surface lab assigned to the competence center Intersurf within the LL&M research building is now capable of measuring very low interfacial tensions between two partially or even non-miscible liquids (especially mixtures of ionic liquids (ILs) with organic solvents) over a wide temperature range. This is of particular interest for the examination of lower as well as upper critical demixing points in such binary systems. Beyond structural and dynamical properties of the systems we are interested in, we now have the additional ability to directly determine this important thermodynamic property. In combination with other experiments as well as computer simulations this improves our understanding of complex fluids and mixtures on a molecular level.
The spinning drop video tensiometer SVT 20N manufactured by Dataphysics, Germany, measures static or time-dependent liquid-liquid interfacial tensions in the range from 1∙10-6 mN/m to 2,000 mN/m over a temperature range between -10 °C and 130 °C applying the spinning drop method. Moreover, it is also able to determine the 2D/3D dilatational relaxation of viscoelastic liquids, the yield point of liquid crystals and the thermal expansion of liquids, too.