Regensburg 2010 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 37: Poster: Colloids and Complex Liquids

CPP 37.11: Poster

Mittwoch, 24. März 2010, 17:30–19:00, Poster B2

Interactions in Thin Aqueous Film of Colloidal Suspensions — •Yan Zeng and Regine von Klitzing — Stranski-Laboratorium, Department of Chemistry, TU Berlin, Strasse des 17.Juni 124, D-10623 Berlin

Colloidal suspensions are omnipresent in daily life and have many technical applications. To understand the interactions between particles in thin film of colloidal suspensions, we perform force measurements by using Colloidal Probe Atomic Force Microscopy (CP-AFM), in which particles show oscillatory force due to the layer formations of particles under spatial confinement. The distance of layers can be figured out from the force profiles and compared with the mean particle distance obtained from Small Angle X-Ray Scattering (SAXS). Thus we know the structuring of colloidal suspensions can be survived from 3D to 2D or not? Particle concentration, particle size and ionic strength of suspensions have been studied both by CP-AFM and SAXS. The effects of Surface charge and surface elasticity have been studied as well by replacing the solid silicon wafer with mica sheet, air/liquid interface, and modified silicon with polyelectrolyte adsorbed layers. Those are measured by CP-AFM and compared with results from Thin Film Pressure Balance (TFPB) in which particle suspensions form thin films between fluid interfaces and shows no dependency of step size on the particle concentrations. The effect of charge on nanoparticles is studied by adding non-ionic surfactants into particle suspensions and by using non-ionic surfactant itself at concentrations above CMC. Latter case shows significant different result as that of charged particles.