Lumping of Distributed Surfactant Terms

Crook et alP assumed that, for dissolved surfactant monomers in the oil and aqueous phase, there are weak interactions between molecules of varying ethylene oxide chain length. This assumption does not look unreasonable as the CMCs of surfactant monomers are normally of the order 10 to 0.1 M and the molecules are nonionic. 

The partition coefficient of a distributed surfactant between oil and water can be de ied as  

Crook et al found that eqn. (6.15) was in good agreement with experimental 

Brooks and Richmond applied eqn. (6.14) to transitional inversion data and used it to predict the variation of the slope of the SAD = 0 inversion line with surfactant concentration at constant temperature. More analytical details on the use of this method are given in refs. 16 and 71. 

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