Spinning Drop Tensiometer

Spinning drop tensiometer is used to measure low to ultra-low interfacial tensions to optimize emulsions and microemulsions [1,2]. The method is based on the optical contour analysis of a drop which is located inside a capillary. Under the monitoring by a high precision camera, the drop of interest is rotated with angular velocity (ω) under a certain rotating speed and tilt angle. Due to the centrifugal force inside the capillary, the denser liquid is pushed to surround the less dense liquid drop outwards. The drop gets pushed along the rotational axis, cylindrically deformed and its interfacial area increases. The interfacial tension counteracts this area increase and thus can be calculated by analysing the equilibrium drop shape according to Young-Laplace, Vonnegut and Cayias-Schechter-Wade models.

Typical measurements:

Outer phase; transparent liquid with higher density, normally water phase, 5 ml.

Inner phase; liquid with lower density than upper phase, 1 ml.

Equipment:

Spinning drop video tensiometer DataPhysics SVT20.

References:

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[1] https://www.dataphysics-instruments.com/products/svt/ (Accessed on 27 Nov 2021)

[2] Marquez R, Forgiarini A.M, Langevin D, Salager J-L, Langmuir 2018, 34, 31, 9252–926

 

Contact:

Dr. Waraporn Wichaita ( 06131-379-723)

Dr. Lucas Caire da Silva ( 06131-379-581)