The persistence length of adsorbed dendronized polymers

Research output: Contribution to journalArticle

Abstract

The persistence length of cationic dendronized polymers adsorbed onto oppositely charged substrates was studied by atomic force microscopy (AFM) and quantitative image analysis. One can find that a decrease in the ionic strength leads to an increase of the persistence length, but the nature of the substrate and of the generation of the side dendrons influence the persistence length substantially. The strongest effects as the ionic strength is being changed are observed for the fourth generation polymer adsorbed on mica, which is a hydrophilic and highly charged substrate. However, the observed dependence on the ionic strength is much weaker than the one predicted by the Odijk, Skolnik, and Fixman (OSF) theory for semi-flexible chains. Low-generation polymers show a variation with the ionic strength that resembles the one observed for simple and flexible polyelectrolytes in solution. For high-generation polymers, this dependence is weaker. Similar dependencies are found for silica and gold substrates. The observed behavior is probably caused by different extents of screening of the charged groups, which is modified by the polymer generation, and to a lesser extent, the nature of the substrate. For highly ordered pyrolytic graphite (HOPG), which is a hydrophobic and weakly charged substrate, the electrostatic contribution to the persistence length is much smaller. In the latter case, we suspect that specific interactions between the polymer and the substrate also play an important role.

Details

Authors
  • Lucie Grebikova
  • Svilen Kozhuharov
  • Plinio Maroni
  • Andrey Mikhaylov
  • Giovanni Dietler
  • A Dieter Schlüter
  • Magnus Ullner
  • Michal Borkovec
Organisations
External organisations
  • University of Geneva
  • Swiss Federal Institute of Technology
  • ETH Zürich
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Chemistry
  • Polymer Chemistry

Keywords

  • Journal Article
Original languageEnglish
Pages (from-to)13498-506
Number of pages9
JournalNanoscale
Volume8
Issue number27
Publication statusPublished - 2016 Jul 21
Publication categoryResearch
Peer-reviewedYes