Micellization - theories and key parameters

There is another reason for this compromise, even for non-ionic surfactants, which do not have a Krafft point. As mentioned previously, an optimum surfactant chain length is about 12-16, as heavier surfactants diffuse very slowly in solution. 

In conclusion, as shown in Table 5.5, miceUization is either an endothermic (positive enthalpy change), e.g. 

Surfactant Gibbs energy change of micellization (kj moM) Enthalpy change of micellization (kJ mol ) Entropy change of micellization 0 IC mol ) 

From various sources (Hiemenz and Rajagopalan, 1997 Prausnitz, Lichtenthaler and de Azevedo, 1999 Hunter, 2001) as summarized by Kontogeorgis and Folas (2010). Reprinted with permission from John Wiley Sons, Ltd. 

Another explanation (of less importance than the hydrophobic effect) is that the hydrocarbon chains of surfactants have a much higher freedom of movement inside the micelles than in the solution consequently, there is a positive entropy change of the surfactants themselves. 

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