Description
Spinning drop tensiometry is the technology of choice for measuring extremely low interfacial tensions. The method is based on the optical contour analysis of a drop. This drop, instead of hanging from a dosing needle and being exposed to gravitation, is located inside of a rotating capillary.
Inside of the capillary the centrifugal force pushes the denser liquid surrounding the drop outwards while the less dense drop gets pushed towards the rotational axis. Hence the drop is de-formed cylindrically and its interfacial area increases. The interfacial tension counteracts this area increase and thus can be determined by analysing the equilibrium drop shape.
The Spinning drop video tensiometer SVT 25 is a compact optical measuring instrument for the determination of low to ultra-low interfacial tensions and rheological interface properties. Highest precision and reproducibility of the measuring results is guaranteed by a well-established measuring technique and first grade mechanical and optical components.
Main features:
- Measurement of low to ultra-low interfacial tensions based on the contour of spinning drops according to models by Vonnegut, Cayias-Schechter-Wade or Young-Laplace
- Oscillation measurements with oscillation periods of 0.5 s …∞ and max. acceleration of 500 rev/s2
- Motorised tilting table
- Fast 6.5-fold zoom lens with integrated continuous fine focus and high-performance camera
- Motorised movable optics for automatically following moving drops
- Precise, fast and easy to use capillary exchange system
- Temperature controlled measuring cells for temperatures ranging from -30 °C to 180 °C
- Automatic calibration function for correcting optical distortions caused by the capillaries (cylindrical lens effects)
- TP 50 control panel with touch screen and precision control wheel
