text: The Van 't Hoff relation is particularly useful for the determination of the micellization enthalpy  of surfactants from the temperature dependence of the critical micelle concentration (CMC):
  However, the relation loses its validity when the aggregation number is also temperature-dependent, and the following relation should be used instead:
  with  and  being the free energies of the surfactant in a micelle with aggregation number  and  respectively. This effect is particularly relevant for nonionic ethoxylated surfactants or polyoxypropylene–polyoxyethylene block copolymers (Poloxamers, Pluronics, Synperonics). The extended equation can be exploited for the extraction of aggregation numbers of self-assembled micelles from differential scanning calorimetric thermograms.