On the Solubilization of Additives into Micelles.

The amount of hydrocarbons or n-alcohols which can be solubilized by micelles of ionic surfactants depends, for a given chain length of the surfactant, very much on the counterions of the surfactant. Surfactants which form rodlike micelles have a particularly high solubilization capacity for aliphatic hydrocarbons and a low one for n-alcohols. These systems usually have strongly binding counterions. Globular micelles, on the other hand, have a low solubilization capacity for aliphatic hydrocarbons and a higher one for n-alcohols. The solubilization of additives into micelles has a strong influence on the shape and the dynamic behavior of these micelles. Aliphatic hydrocarbons lead to a decrease of the lengths of the rods and finally to a transition of the rodlike micelles to globular structures. As a consequence of the transition, the aggregation number of the micelles is decreasing with an increasing amount of hydrocarbon until the transition is completed.