title: Entropic effects, shape, and size of mixed micelles formed by copolymers with complex architectures.
abstract: The entropic effects in the comicellization behavior of amphiphilic AB copolymers differing in the chain size of solvophilic A parts were studied by means of molecular dynamics simulations. In particular, mixtures of miktoarm star copolymers differing in the molecular weight of solvophilic arms were investigated. We found that the critical micelle concentration values show a positive deviation from the analytical predictions of the molecular theory of comicellization for chemically identical copolymers. This can be attributed to the effective interactions between copolymers originated from the arm size asymmetry. The effective interactions induce a very small decrease in the aggregation number of preferential micelles triggering the nonrandom mixing between the solvophilic moieties in the corona. Additionally, in order to specify how the chain architecture affects the size distribution and the shape of mixed micelles we studied star-shaped, H-shaped, and homo-linked-rings-linear mixtures. In the first case the individual constituents form micelles with preferential and wide aggregation numbers and in the latter case the individual constituents form wormlike and spherical micelles.
authors.affiliation: Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kalogirou
authors.affiliation: Department of Materials Science & Engineering, University of Ioannina, 45110 Ioannina, Greece.
authors.forename: Leonidas N
authors.initials: LN
authors.lastname: Gergidis
authors.affiliation: Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece.|Chemical Engineering Program, Texas A&M University at Qatar, P.O. Box 23874, Doha, Qatar.
authors.forename: Othonas
authors.initials: O
authors.lastname: Moultos
authors.affiliation: Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece.
authors.forename: Costas
authors.initials: C
authors.lastname: Vlahos