Sigma 700/701

The Sigma 700 and 701 force tensiometers offer a robust and precise method for measuring the static surface and interfacial tension of liquids. These instruments enable direct measurements, providing insights into various material and surface properties including dynamic contact angle, surface free energy, critical micelle concentration (CMC), and wettability.

The obtained data serves a multitude of purposes such as assessing adhesion, absorption, adsorption, cleanliness, surface heterogeneity, density, spreading, porosity, powder or sedimentation wettability, material solubility, biocompatibility, and lubricity of solid surfaces.

Density force tensiometry has emerged as the preferred technique for numerous industrial standards concerning liquid characterization. It is notably the most commonly employed method for determining the critical micelle concentration (CMC) of surfactants. Additionally, it stands as the sole method capable of determining the absorption and contact angle of packed powder or fiber beds utilizing the Washburn method. Sigma force tensiometers also facilitate the study of textile wetting and individual fiber behavior.

Measurement principle When a liquid comes into contact with the surface of a solid, it typically forms a meniscus, causing the liquid to be drawn upward. The force exerted by this meniscus is measured and analyzed to ascertain surface tension. Employing high surface free energy probes like a platinum Du Noüy ring or Wilhelmy plate enables accurate measurement of these forces. All Sigma force tensiometers employ plates or employ push and pull modes with rings to measure both surface and interfacial tension.