Force Tensiometers

Sigma force tensiometers are precision instruments with unparalleled ease of use. They all feature high precision balances and mechanics, intuitive software and open design for easy access to the different parts of the instrument.  Whatever your research objectives, there is a Sigma instrument to meet your needs.

Sigma 700 / 701 Force Tensiometers

Sigma 700 & 701

State-of-the-art force tensiometers, providing highly accurate measurements of surface and interfacial tension, dynamic contact angles, surface free energy.

157 Sigma 702aSigma 702 and Sigma 702ET

Standalone force tensiometers offering high resolution and precision for surface and interfacial tension measurements, as well as non-automatic cmc.

Sigma 703D

A simple standalone and robust digital force tensiometer for accurate measurement of surface and interfacial tension of liquids by DuNouy ring or Wilhelmy plate.


Force tensiometry has become the method of choice for many industrial standards related to characterization of liquids. It is also the most widely used technique for measuring critical micelle concentration of surfactants. In addition, it is the only method to determine the absorption and contact angle of a packed powder or of fiber beds using the Washburn method.

Sigma Force Tensiometers are widely used in research, quality control and process control for the determination of:

  • Surface tension
  • Interfacial tension
  • Critical micelle concentration
  • Powder wettability
  • Dynamic contact angle
  • Sedimentation wettability
  • Surface free energy
  • Absorption
  • Cleanliness
  • Surface heterogeneity
  • Density

The measurement of surface and interfacial tension as performed by a Sigma force tensiometer is based on force measurements of the interaction of a probe with the surface of interface of two fluids.  You may perform interfacial tension measurements just like surface tension measurements by ensuring that the bulk of the probe is submersed in the light phase prior to beginning the experiment.

In these experiments a probe is hung on a balance and brought into contact with the liquid interface tested. The forces experienced by the balance as the probe interacts with the surface of the liquid can be used to calculate surface tension. The forces present in this situation depend on the following factors: size and shape of the probe, contact angle of the liquid/solid interaction and surface tension of the liquid. The size and shape of the probe are easily controlled. The contact angle is controlled to be zero (complete wetting). This is achieved by using probes with high-energy surfaces. Probes available are made of a platinum/iridium alloy that ensures complete wetting and easy and reliable cleaning.

The mathematical interpretation of the force measurements depends on the shape of the probe used. Two types of probes are commonly used, the Du Noüy ring and the Wilhelmy plate. A metal rod can also be used to limit the liquid sample volume.

Standards for Force Tensiometers

Here you can find information about the following standards:

  • ISO 1409:2006
  • ASTM D1331-11
  • ASTM D971-12
  • OECD 115
  • EN 14210
  • EN 14370