24 research outputs found
Shape characteristics of the aggregates formed by amphiphilic stars in water: dissipative particle dynamics study
We study the effect of the molecular architecture of amphiphilic star
polymers on the shape of aggregates they form in water. Both solute and solvent
are considered at a coarse-grained level by means of dissipative particle
dynamics simulations. Four different molecular architectures are considered:
the miktoarm star, two different diblock stars and a group of linear diblock
copolymers, all of the same composition and molecular weight. Aggregation is
started from a closely packed bunch of molecules immersed into
water. In most cases, a single aggregate is observed as a result of
equilibration, and its shape characteristics are studied depending on the
aggregation number . Four types of aggregate shape are observed:
spherical, rod-like and disc-like micelle and a spherical vesicle. We estimate
"phase boundaries" between these shapes depending on the molecular
architecture. Sharp transitions between aspherical micelle and a vesicle are
found in most cases. The pretransition region shows large amplitude
oscillations of the shape characteristics with the oscillation frequency
strongly dependent on the molecular architecture.Comment: 10 pages, 7 figure