Micelles energy barriers

In contrast, systems that form stable micellar aggregates that can be compared to experimentally observed micelles have large free energy barriers separating the aggregated and free states. In our previous work (Floriano et al., 1999) we have shown that for the surfactants H3T3 and H4T4, we have... 

The Smith-Ewart mechanism does not take into account any polymerization in the aqueous phase. This may be true for monomers that are quite insoluble in water, like styrene, but appears unlikely for more hydrophilic ones like methyl methacrylate or vinyl acetate. In addition, it was calculated by Flory that there is insufficient time for a typical cation radical (like a sulfate ion radical) to add to a dissolved molecule of monomer like styrene before it becomes captured by a micelle. This was argued against, however, on the ground that Flory s calculations fail to consider the potential energy barrier at the micelle surfaces from the electrical double layer. This barrier would reduce the rate of diffusion of the radical ions into the micelles. ... 

Other applications of Marcus theory include calculation of energy barriers in micelle reactions, with total micellar charges estimated via work terms, " assignment of outer-sphere mechanisms in reactions of organic radicals, and calculation of the unknown redox potential of one reagent, either by curve fitting, or by a linear extrapolation of rates to the diffusion-controlled limit. ... 

The lack of a strong dependence of the mass transfer on micelle concentration for ionic surfactants may result from electrostatic repulsions between the emulsion droplets and micelles, which would provide a high energy barrier preventing droplet/micelle collisions. Taisne et al. estimated that the disjoining pressure between a micelle and emulsion droplet would be of the order of 10 Pa, indicating little probability for a direct collisional mechanism. Karabomi et al. also noted in their molecular dynamics simulations that the collision mechanism is more likely with nonionic surfrctants and less likely with ionic surfactants. ... 

In view of this phase concept which is confirmed by the micellization phenomena in many nonpolar detergent solutions, it has been suggested by Eicke and Christen40 that in line with this reasoning a nucleation step is to be expected (in the approximation of the phase separation model). In order to explain the origin of the energy necessary to overcome the potential barrier associated with the postulated... 

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