Inverted critical adsorption of polyelectrolytes in confinement

Sidney J. De Carvalho, Ralf Metzler, Andrey G. Cherstvy

    Research output: Contribution to journalArticleScientificpeer-review

    55 Citations (Scopus)

    Abstract

    What are the fundamental laws for the adsorption of charged polymers onto oppositely charged surfaces, for convex, planar, and concave geometries? This question is at the heart of surface coating applications, various complex formation phenomena, as well as in the context of cellular and viral biophysics. It has been a long-standing challenge in theoretical polymer physics; for realistic systems the quantitative understanding is however often achievable only by computer simulations. In this study, we present the findings of such extensive Monte-Carlo in silico experiments for polymer-surface adsorption in confined domains. We study the inverted critical adsorption of finite-length polyelectrolytes in three fundamental geometries: planar slit, cylindrical pore, and spherical cavity. The scaling relations extracted from simulations for the critical surface charge density σ<inf>c</inf> - defining the adsorption-desorption transition - are in excellent agreement with our analytical calculations based on the ground-state analysis of the Edwards equation. In particular, we confirm the magnitude and scaling of σ<inf>c</inf> for the concave interfaces versus the Debye screening length 1/κ and the extent of confinement a for these three interfaces for small κa values. For large κa the critical adsorption condition approaches the known planar limit. The transition between the two regimes takes place when the radius of surface curvature or half of the slit thickness a is of the order of 1/κ. We also rationalize how σ<inf>c</inf>(κ) dependence gets modified for semi-flexible versus flexible chains under external confinement. We examine the implications of the chain length for critical adsorption - the effect often hard to tackle theoretically - putting an emphasis on polymers inside attractive spherical cavities. The applications of our findings to some biological systems are discussed, for instance the adsorption of nucleic acids onto the inner surfaces of cylindrical and spherical viral capsids.

    Original languageEnglish
    Pages (from-to)4430-4443
    Number of pages14
    JournalSoft Matter
    Volume11
    Issue number22
    DOIs
    Publication statusPublished - 14 Jun 2015
    Publication typeA1 Journal article-refereed

    Publication forum classification

    • Publication forum level 2

    ASJC Scopus subject areas

    • General Chemistry
    • Condensed Matter Physics

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