Coarse-grained mean field simulations of triblock copolymer systems. The effect of flexibility on the micellization behavior.

Identifier:  TFM:300

Handle: https://hdl.handle.net/20.500.11797/TFM300

Authors:  Pantelidou, Maria

Abstract:
Micelles appear when surfactants in an aqueous media, start to self-assembly into aggregates above a certain concentration. This physical mechanism of the micelle formation is key to developing new intelligent materials having a strong impact in selective drug delivery, tissue repair, molecular recognition, and many others. In this work, Single Chain Mean Field Theory (SCMF) is used as a simulation method in order to study the effect of changing the flexibility of surfactant chain in the micellization behavior. Critical Micelle Concentration (CMC), aggregation number and micellar size and architecture were examined by using a coarse-grained model for the L44 Pluronic, a trademarked type of triblock copolymer in water at 37 0C . We found that increasing the chain stiffness, the CMC decreases. In addition, in agreement with previous experimental and theoretical studies we observed a significant dependence between the flexibility of the surfactant chain and the aggregation number. On increasing chain stiffness the aggregation number is increased strongly. Furthermore, a structural analysis based on surfactant heads and tail fraction distributions, as well as solvent fraction distribution, show us that stiffening the whole chain the resulting micellar aggregate is larger than an aggregate composed by flexible chains, without deviations from spherical symmetry.