Regensburg 2002 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 16: Polymere Netzwerke und Polymere mit besonderer Architektur

CPP 16.3: Vortrag

Donnerstag, 14. März 2002, 10:00–10:20, H38

Confirmation of spherical Polyelectrolyte Brushes characterised by anomalous small-angle X-ray scattering (ASAXS) — •Nico Dingenouts¹, Matthias Ballauff¹, Christos Likos², and T. Narayanan³ — ¹Polymer Institut, Universität Karlsruhe, Kaiserstr. 12, 76128 Karlsruhe — ²Institut für theoretische Physik II, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf — ³ESRF, Grenoble

Spherical polyelectrolyte brushes are composed of latex particles of colloidal dimensions with chemical grafted polyelectrolyte chains on their surfaces. The polyelectrolyte chains are highly charged. The chemical nature, the length and the grafting density of the chains can be varied in a wide range.

Here, we present a experimental study of a spherical polyelectrolyte brush about the confirmation of the chains and the distribution of the counterions. Due to the high number of counterions the osmotic pressure of the ions and the electrostatics are is responsible for the confimation and the properties of the system. Two different methods were used: The osmotic coefficient, determined via osmotic pressure measurements gives information about the free counterions and anomalous small-angle X-ray scattering that is sensitive to the confirmation of the polymer chains and the distribution of counter ions inside the brush. The results are compared with computer simulations and and theoretical models recently developed by Ch. Likos.