Salt-regulated attraction and repulsion of spherical polyelectrolyte brushes towards polyelectrolyte multilayers

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Christoph Hanske - , University of Bayreuth (Author)
  • Christian Schneider - , University of Bayreuth, Helmholtz Centre Berlin for Materials and Energy (Author)
  • Markus Drechsler - , University of Bayreuth (Author)
  • Alexander Wittemann - , University of Bayreuth, University of Konstanz (Author)
  • Andreas Fery - , University of Bayreuth (Author)

Abstract

Adsorption of colloidal particles presents an interesting alternative to the modification of surfaces using covalent coupling or physisorption of molecules. However, to tailor the properties of these materials full control over the effective particle-substrate interactions is required. We present a systematic investigation of the adsorption of spherical polyelectrolyte brushes (SPB) onto polyelectrolyte multilayers (PEM). A brush layer grafted from colloidal particles allows the incorporation of various functional moieties as well as the precise adjustment of their adsorption behaviour. In the presence of oppositely charged surfaces the amount of adsorbed SPB monotonically increases with the ionic strength, whereas equally charged substrates efficiently prevent colloidal attachment below a threshold salt concentration. We found that the transition from the osmotic to the salted brush regime at approximately 100 mM coincided with a complete loss of substrate selectivity. In this regime of high ionic strength, attractive secondary interactions become dominant over electrosteric repulsion. Due to the soft polyelectrolyte corona a surface coverage exceeding the theoretical jamming limit could be realized. Both the adsorption kinetics and the resulting thin film morphologies are discussed. Our study opens avenues for the production of two-dimensional arrays and three-dimensional multilayered structures of SPB particles. This journal is

Details

Original languageEnglish
Pages (from-to)4196-4203
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume14
Issue number12
Publication statusPublished - 28 Mar 2012
Peer-reviewedYes
Externally publishedYes

External IDs

PubMed 22354351