Repulsive and attractive depletion forces mediated by nonadsorbing polyelectrolytes in the Donnan limit

J. Landman, Max Schelling, Remco Tuinier, Mark Vis*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

In mixtures of colloids and nonadsorbing polyelectrolytes, a Donnan potential arises across the region between surfaces that are depleted of the polyelectrolyte and the rest of the system. This Donnan potential tends to shift the polyelectrolyte density profile toward the colloidal surface and leads to the local accumulation of polyelectrolytes. We derive a zero-field theory for the disjoining pressure between two parallel flat plates. The polyelectrolyte is allowed to enter the confined interplate region at the cost of a conformational free energy penalty. The resulting disjoining pressure shows a crossover to a repulsive regime when the interplate separation gets smaller than the size of the polyelectrolyte chain, followed by an attractive part. We find a quantitative match between the model and self-consistent field computations that take into
account the full Poisson–Boltzmann electrostatics.
Original languageEnglish
Article number164904
Number of pages13
JournalJournal of Chemical Physics
Volume154
Issue number16
DOIs
Publication statusPublished - 23 Apr 2021

Fingerprint Dive into the research topics of 'Repulsive and attractive depletion forces mediated by nonadsorbing polyelectrolytes in the Donnan limit'. Together they form a unique fingerprint.

Cite this