Regensburg 2019 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 7: Interfaces and Thin Films (joint session CPP/DY)

DY 7.2: Vortrag

Montag, 1. April 2019, 15:15–15:30, H14

Competition of structural and electrostatic forces in colloidal dispersions confined between of two charged surfaces — •Michael Ludwig and Regine von Klitzing — Soft Matter at Interfaces, Department of Physics, Technische Universität Darmstadt

Structural forces can be observed when pure solvents and ionic liquids, as well as dispersions containing nanoparticles, micelles, polymers or polyelectrolytes are confined between two smooth surfaces into a thin liquid film. Upon surface-approach, liquid matter has to be depleted from the vicinity of the surfaces, altering the interactions between the surfaces.

The present study addresses structural forces across thin films of suspensions of nanoparticles (NP) confined between two charged surfaces measured with a colloidal-probe atomic force microscope (CP-AFM). Special attention is drawn to the transition from diluted to concentrated NP-packing and to the effect of the outer surface charge. An extended fitting procedure was introduced to accurately fit experimental data. The need of an additional repulsive contribution to the fitting formula will be discussed in terms of the DLVO-framework.