Tensiometry

Tensiometry is the measurement of interfacial tension, typically of the interface between a liquid and a solid, gas, or another liquid.

EAG Laboratories performs dynamic contact angle and force tensiometry measurements using the Dataphysics DCAT21. The DCAT21 is equipped with a high precision balance and z-axis variable speed stage for reproducible measurements of the change in apparent mass of a sample when in contact with a liquid. All measurements can be performed under temperature controlled conditions from -20 ºC to 100 ºC.

Liquids

Surface Tension: The surface tension of a liquid in air can be measured using the Wilhelmy plate method.

Liquid-Liquid Interfacial Tension: The du Noüy ring method can be used to determine the interfacial tension between two liquids by measuring the tensile force required to breach the interface.

Density: The density of a liquid can be measured with high precision by measuring the buoyancy of a solid with well-defined geometry when it is immersed in the liquid.

Solids

Density: The density of solids can be analyzed by measuring the mass of the solid and calculating the volume by the buoyant force when the solid is immersed in a liquid of known density.

Dynamic Contact Angle: The contact angle of a liquid-solid interface can be measured by the tensile force applied while the solid is being immersed (advancing contact angle) and withdrawn (receding contact angle) from a liquid with known or measured surface tension and density. Thin films can also be measured in this manner.

Powders

Density: The density of a powder can be determined by the same measurement as the density of a solid.

Contact Angle: By treating the interstitial space of a powder as though it were a bundle of capillaries, the relationship between the contact angle and the capillary constant can be determined.