Surfactants and the Reduction of Surface Tension

The fundamental principle underlying our present understanding of surface activity is the Gibbs adsorption equation discussed in more detail in Section 

FIGURE 8.8. In a surfactant solution, the surface tension will typically change rapidly over a relatively small concentration range and then level off at some characteristic minimum value. The exact shape of the curve will depend on the molecular characteristics of the surfactant and its purity. 

A large body of literature has grown up around the question of how one can relate the chemical structure of a surfactant to its surface activity in various situations. At the present time, most such structure-property relationships are semiquantitative at best, but they can serve one well as a guide to the choice of the best surfactant for a given situation. Several works reviewing the hterature in that area are cited in the Bibliography, and some specific examples will be noted in the appropriate contexts of later chapters. 

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