Increasing unimer concentration for micelles preparation leads to increase of micelle size or increase in number of micelles? What are the mechanisms that dictate the behavior of the micelle population when the unimer concentration is increased (e.g. polymeric micelle)?
Miguel Pereira-Silva
The size of micelles is determined by the size of the polymer monomer and its chemical structure. As the micelle monomer concentration increases, the number of micelles increases. It should be borne in mind that the micelles are distributed in size around a certain average.
in addition, for some surfactants, shape of micelles changes around certain higher surfactant concentrations, and with this their size, e.g., transformation from spherical to rod shape.
Titus, why would that be the case? The curvature of the surfactant monolayer shouldn't change, should it? Eventually, spherical micelles will self-assemble into a cubic liquid crystal phase (e.g., as the concentration of poloxamer 407 is increased above about 12% a cubic phase is formed. Below this concentration there are simply spherical micelles...
Jeffry G Weers - this happens, e.g., change of cationic micelles from spherical to rod-like. For ionic surfactants increasing surfactant concentration means also increasing electrolyte concentration changing packing of ionic surfactant head groups.
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