The Force Tensiometer – K100 performs high precision, automatic and reliable measurements of surface tension and interfacial tension, critical micelle concentration CMC and contact angle on solids, fibers and powders. With high-quality components and a uniquely wide range of methods, the instrument carries out many tasks in the field of surfactant analysis and wetting measurement for your quality assurance or research. The simple changeover between different measuring methods takes place entirely without reconfiguring the instrument. The surface tension measurement is an automatic system to measure surface energy and will be based on tensiometer method using ring and plates


  • Determination of the effectiveness and efficiency of surfactants by CMC measurement

  • Wetting behavior of tablets, pharmaceutical active ingredients and excipients

  • Wetting and adhesion of coatings

  • Development of cosmetic products

  • Wetting of fiber bundles and textiles

  • Checking of surface modifications

Measurement method

Wilhelmy plate method: The force acting in the tensile direction when moving a plate-shaped solid vertically in a liquid is measured. This force depends on the contact angle as well as on the surface tension and the wetted length. Instrument: K100

Powder contact angle measurement using the Washburn method: The increase in weight of an immersed powder-filled tube is measured with respect to time. The rate of rise of the liquid column depends, among other things, on the contact angle. Instrument: K100

Useful links

Background knowledge

Critical surface tension

According to the Zisman method, the critical surface tension is the surface tension at which a liquid just completely wets a solid. The surface tension of different liquids is plotted against the cosine of the contact angle θ in order to determine the critical surface tension. The value of the surface tension from the regression equation for cos θ = 1 (contact angle = 0°) corresponds to the critical surface tension.

Dynamic surface tension

The dynamic surface tension (SFT) or interfacial tension (IFT) is the value of the SFT or IFT referred to a particular surface age or interface age. In the case of liquids with surface-active substances (surfactants), this can differ from the equilibrium value.

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