ISO 4311:1979

Anionic and non-ionic surface active agents — Determination of the critical micellization concentration — Method by measuring surface tension with a plate, stirrup or ring

The method is carried out in the following way: Determination of the surface tension of a series of solutions whose concentrations bracket the critical micellization concentration. Plotting of the graph of surface tension as a function of the logarithm of the concentration: the critical micellization concentration corresponds to a singular point on this curve. In this point the curve shows a sharp change of slope.