Computer simulation of bottle-brush polymers with flexible backbone: Good solvent versus theta solvent conditions

Autor(en)

Panagiotis Theodorakis, Hsiao-Ping Hsu, Wolfgang Paul, Kurt Binder

Abstrakt

By Molecular Dynamics simulation of a coarse-grained bead-spring type model for a cylindrical molecular brush with a backbone chain of Nb effective monomers to which with grafting density σ side chains with N effective monomers are tethered, several characteristic length scales are studied for variable solvent quality. Side chain lengths are in the range 5≤N≤40, backbone chain lengths are in the range 50≤Nb≤200, and we perform a comparison to results for the bond fluctuation model on the simple cubic lattice (for which much longer chains are accessible, Nb≤1027, and which corresponds to an athermal, very good, solvent). We obtain linear dimensions of side chains and the backbone chain and discuss their N-dependence in terms of power laws and the associated effective exponents. We show that even at the Theta point the side chains are considerably stretched, their linear dimension depending on the solvent quality only weakly. Effective persistence lengths are extracted both from the orientational correlations and from the backbone end-to-end distance; it is shown that different measures of the persistence length (which would all agree for Gaussian chains) are not mutually consistent with each other, and depend distinctly both on Nb and the solvent quality. A brief discussion of pertinent experiments is given.

Organisation(en)

Computergestützte Physik und Physik der Weichen Materie

Externe Organisation(en)

Johannes Gutenberg-Universität Mainz, Martin-Luther-Universität Halle-Wittenberg

Journal

Journal of Chemical Physics

Band

135

Anzahl der Seiten

13

ISSN

0021-9606

DOI

https://doi.org/10.1063/1.3656072

Publikationsdatum

2011

Peer-reviewed

Ja

ÖFOS 2012

103005 Atomphysik, 103018 Materialphysik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/a0211adb-589b-41bf-a0bc-c030d4e33808