ISO 6889-86

Surface active agents – Determination of interfacial tension by drawing up liquid films

This standard covers the measurement of the maximum force which can be exerted before the film breaks, the force being exerted vertically on a stirrup or ring, in contact with he interfacial liquid film between two immiscible liquid phases placed in a measuring cup, in order to draw up the interfacial film. The force must pass through a maximum, otherwise the measurement is not valid.