Interactions between charged surfaces mediated by stiff, multivalent zwitterionic polymers

Klemen Bohinc, Jurij Reščič, Leo Lue

Research output: Contribution to journalArticle

3 Citations (Scopus)
53 Downloads (Pure)

Abstract

The interaction between like-charged objects in electrolyte solutions can be heavily altered by the presence of multivalent ions which possess a spatially distributed charge. In this work, we examine the influence of stiff, multivalent zwitterionic polymers on the interaction between charged surfaces using a splitting field theory previously shown to be accurate from the weak to the intermediate through to the strong electrostatic coupling regimes. The theory is compared to Monte Carlo simulations and good agreement is found between both approaches. For surface separations shorter than the polymer length, the polymers are mainly oriented parallel to the surfaces, and the surface-surface interaction is repulsive. When the surface separation is comparable to the length of polymers, the polymers have two main orientations. The first corresponds to the polymers adsorbed to the surface with their centers located near to or in contact with the surface; the second corresponds to polymers which are perpendicular to the charged surfaces, bridging both surfaces and leading to an attractive force between them. Increasing the surface charge density leads to a more pronounced attraction via bridging. At surface separations greater than the polymer length, the polymers in the center of the system are still mainly perpendicular to the surfaces, due to "chaining" between zwitterions that enable them to bridge the surfaces at larger separations. This leads to an attractive interaction between the surfaces with a range significantly longer than the length of the polymers.
Original languageEnglish
Pages (from-to)4397-4405
Number of pages10
JournalSoft Matter
Volume12
Issue number19
Early online date18 Apr 2016
DOIs
Publication statusPublished - 21 May 2016

Keywords

  • multivalent ions
  • multivalent zwitterionic polymers
  • charged surfaces
  • splitting field theory
  • Monte Carlo simulations

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1 Citation (Scopus)
2 Downloads (Pure)

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