[8] Effect of Polymer Chain Polydispersity on the Size of Spherical Micelles Formed in Solution
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Amphiphilic molecules in solution display a rich diversity of micellar morphologies. Micellar structures and their size distribution are expected to depend on molecular parameters like, chain length of amphiphilic molecules, the solvophobic to solvophilic ratio, the intermolecular interactions etc. In this work we investigate the effect of polymer length polydispersity on the size of spherical micelles formed by diblock copolymers in solution. Using self-consistent field theoretic simulations, we show that monodisperse polymers favor formation of micelles of different sizes, whereas polydisperse polymers favor the formation of micelles with monodisperse size distribution. Differences in the free energetic contributions associated with the chain stretching explains above differences in the size of micelles formed by monodisperse and polydisperse diblock copolymers in solution. In the micelles formed by monodisperse polymers, chains are stretched to different lengths to accommodate micelles of different sizes. On the other hand such a chain stretching is found to be very narrow in micelles formed by polydisperse polymers.