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High elongation of polyelectrolyte chains in the osmotic limit of spherical polyelectrolyte brushes: a study by cryogenic transmission electron microscopy.

Authors
  • Wittemann, Alexander
  • Drechsler, Markus
  • Talmon, Yeshayahu
  • Ballauff, Matthias
Type
Published Article
Journal
Journal of the American Chemical Society
Publication Date
Jul 13, 2005
Volume
127
Issue
27
Pages
9688–9689
Identifiers
PMID: 15998064
Source
Medline
License
Unknown

Abstract

We investigate the conformation of long polyelectrolyte chains attached to colloidal latex particles by cryogenic transmission electron microscopy (cryo-TEM). The dense grafting of the polyelectrolyte chains ("polyelectrolyte brush") leads to a confinement of the counterions and a concomitantly high osmotic pressure within the polyelectrolyte layer attached to the core particles. Cryo-TEM has provided first model-independent direct proof for the strong stretching of the polyelectrolyte chains by direct visualization. If salt is added, cryo-TEM clearly shows how chains collapse because of the strong screening of the electrostatic interaction. Moreover, the analysis of interacting particles by cryo-TEM shows that the polyelectrolyte chains retract at close contact. Hence, we demonstrate how cryo-TEM can be used to analyze directly the spatial structure of polyelectrolyte brushes in situ.

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