Shape characteristics of the aggregates formed by amphiphilic stars in water: dissipative particle dynamics study

• Datum: 2017
• Hauptverfasser: Kalyuzhnyi, O.Y., Ilnytskyi, J.M., C. von Ferber
• Format: Artikel
• Sprache: English
• Veröffentlicht: Інститут фізики конденсованих систем НАН України 2017
• Schriftenreihe: Condensed Matter Physics
• Online Zugang: https://nasplib.isofts.kiev.ua/handle/123456789/156969
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Zitieren: Shape characteristics of the aggregates formed by amphiphilic stars in water: dissipative particle dynamics study / O.Y. Kalyuzhnyi, J.M. Ilnytskyi, C. von Ferber // Condensed Matter Physics. — 2017. — Т. 20, № 1. — С. 13802: 1–10. — Бібліогр.: 36 назв. — англ.

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 Na 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 Na. 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.