Journal Article

FZJ-2017-00316

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Polymer conformations in ionic microgels in the presence of salt: Theoretical and mesoscale simulation results

Kobayashi, H. ; Halver, R.FZJ* ; Sutmann, G.FZJ* ; Winkler, R. G. (Corresponding author)FZJ*

2017
MDPI Basel

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Please use a persistent id in citations: http://hdl.handle.net/2128/13419  doi:10.3390/polym9010015

Abstract: We investigate the conformational properties of polymers in ionic microgels in the presence of salt ions by molecular dynamics simulations and analytical theory. A microgel particle consists of coarse-grained linear polymers, which are tetra-functionally crosslinked. Counterions and salt ions are taken into account explicitly, and charge-charge interactions are described by the Coulomb potential. By varying the charge interaction strength and salt concentration, we characterize the swelling of the polyelectrolytes and the charge distribution. In particular, we determine the amount of trapped mobile charges inside the microgel and the Debye screening length. Moreover, we analyze the polymer extension theoretically in terms of the tension blob model taking into account counterions and salt ions implicitly by the Debye–Hückel model. Our studies reveal a strong dependence of the amount of ions absorbed in the interior of the microgel on the electrostatic interaction strength, which is related to the degree of the gel swelling. This implies a dependence of the inverse Debye screening length κ on the ion concentration; we find a power-law increase of κ with the Coulomb interaction strength with the exponent 3/5 for a salt-free microgel and an exponent 1/2 for moderate salt concentrations. Additionally, the radial dependence of polymer conformations and ion distributions is addressed

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Contributing Institute(s):

1. Theorie der Weichen Materie und Biophysik (IAS-2)
2. Jülich Supercomputing Center (JSC)

Research Program(s):

1. 551 - Functional Macromolecules and Complexes (POF3-551) (POF3-551)
2. 511 - Computational Science and Mathematical Methods (POF3-511) (POF3-511)

Appears in the scientific report 2017

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Database coverage:
; ; ; ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; Ebsco Academic Search ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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