scope:

Scope and field of application

This International Standard specifies a test method, by measuring the drop volume, for the determination of the interfacial tension between two liquid phases.

It is particularly suitable for the measurement of the inter-facial tension between two solutions of surface active agents in aqueous or organic solvents, and provides some advantages compared with the method by drawing up liquid films (ISO 6889), which are the following :

- determination of interfacial tension between two liquid phases containing all types of surface active agents, including cationic surface active agents; 

- accurate measurement of low interfacial tensions of the order of 1 mN/m;

- repeatability standard deviation less than + 0,5 mN/m (acceptable for control in industrial laboratories);

- determination of interfacial tension of viscous liquids;

- determination of inter-facial tension on only small amounts of the solution;

- time dependence of the inter-facial tension can be measured using a simple automatic apparatus.