Dresden 2006 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 5: Polyelectrolytes

CPP 5.5: Vortrag

Montag, 27. März 2006, 15:45–16:00, ZEU 160

Structuring of polyelectrolytes in thin aqueous nanofilms — •Dan Qu¹, Katarzyna Ciunel², Jan Skov Pedersen³, Tommy Nylander⁴, and Regine v. Klitzing⁵ — ¹MPI für Kolloid- und Grenzflächenforschung, D-14224 Potsdam — ²Stranski-Laboratorium, TU Berlin, Str, d, 17. Juni 112, D-10623 Berlin — ³Department of Chemistry, University of Aarhus, Langelandsgade 140, DK-8000 Aarhus C — ⁴Department of Chemistry I, Lund University, Box 124 SE-221 00 Lund — ⁵Institut für Physikalische Chemie, CAU Kiel, Ludewig-Meyn-Strasse 8, D-24118 Kiel

Confinement effects on the structuring of polyelectrolyte chain in aqueous media are studied within nanofilms. The effect of interfaces is studied by choosing films with different surfaces, which are foam films (air/liquid/air), wetting films and films between two solid interfaces. The measurements are carried out in a Thin Film Pressure Balance (TFPB), a Colloidal Probe Atomic Force Microscope (CP-AFM) and a Surface Force Apparatus (SFA). In the semi-dilute regime the confined polyelectrolyte solutions show a force oscillation in a TFPB and in a CP-AFM. While in CP-AFM the whole oscillation is detectable, the TFPB measures only the repulsive parts which leads to steps in the isotherm. The step width corresponds to the period of the oscillation which leads to the conclusion that the properties of the interfaces do not affect the structuring of the polyelectrolytes. In addition the comparison between CP-AFM and SAXS studies shows that there is no confinement effect on the characteristic lengths of the polyelectrolyte system and the counterion distribution.