Measurement and estimation methods for surface tensions

There are many methods for measuring surface and interfacial tensions of liquids and liquid-liquid interfaces. The most common ones are based on the Du Nouy 

Tensionmeter, the Wilhelmy plate, measuring the capillary rise of liquids or the Lying Drop and Pendant Drop methods. These and other methods are described in sev-CTal textbooks (Pashley and Karaman, 2004 Shaw, 1992 Hiemenz and Rajagopalan, 1997 Goodwin, 2004). They will not be further discussed here. 

When not available, liquid surface tensions (pure compounds and solutions) can be estimated using predictive methods like those based on parachors and group contributions, solubility parametes (including Hansoi solubility parameters) and corresponding states. Alternatively, they can be estimated from thermodynamic models like UNIFAC and SAFT combined with the gradient or the density functional theories. For a review of the latter, see Kontogeorgis and Folas (2010). Some of the most important direct methods for estimating surface tension arc briefly described here. 

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