Cluster Formation in Solutions of Polyelectrolyte Rings

Autor(en)

Roman Staňo, Jan Smrek, Christos N. Likos

Abstrakt

We use molecular dynamics simulations to explore concentrated solutions of semiflexible polyelectrolyte ring polymers, akin to the DNA mini-circles, with counterions of different valences. We find that the assembly of rings into nanoscopic cylindrical stacks is a generic feature of the systems, but the morphology and dynamics of such a cluster can be steered by the counterion conditions. In general, a small addition of trivalent ions can stabilize the emergence of clusters due to the counterion condensation, which mitigates the repulsion between the like-charged rings. Stoichiometric addition of trivalent ions can even lead to phase separation of the polyelectrolyte ring phase due to the ion-bridging effects promoting otherwise entropically driven clustering. On the other hand, monovalent counterions cause the formation of stacks to be re-entrant with density. The clusters are stable within a certain window of concentration, while above the window the polyelectrolytes undergo an osmotic collapse, disfavoring ordering. The cluster phase exhibits characteristic cluster glass dynamics with arrest of collective degrees of freedom but not the self-ones. On the other hand, the collapsed phase shows arrest on both the collective and single level, suggesting an incipient glass-to-glass transition, from a cluster glass of ring clusters to a simple glass of rings.

Organisation(en)

Computergestützte Physik und Physik der Weichen Materie

Journal

ACS Nano

Band

17

Seiten

21369–21382

Anzahl der Seiten

14

ISSN

1936-0851

DOI

https://doi.org/10.1021/acsnano.3c06083

Publikationsdatum

09-2023

Peer-reviewed

Ja

ÖFOS 2012

103023 Polymerphysik

Schlagwörter

ASJC Scopus Sachgebiete

Allgemeiner Maschinenbau, Allgemeine Physik und Astronomie, Allgemeine Materialwissenschaften

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/e7b8a33b-4b6c-4ab3-b22f-1b4a4f579c4a