Dresden 2014 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 16: Interfaces and Thin Films II

CPP 16.3: Vortrag

Dienstag, 1. April 2014, 10:00–10:15, ZEU 114

Scaling theory for compressed polymer-brush bilayers — •Torsten Kreer — Leibniz Institut für Polymerforschung Dresden, 01069 Dresden, Germany

When linear macromolecules are grafted densely onto a surface, the individual chains are forced to stretch away from the surface plane forming a polymer brush. Polymer brushes allow one to tune surface properties by modification of the functionality or the molecular parameters, i.e., chain length and density of the grafted chains. Thus, they are important in many respects, e.g. for the stabilization of colloidal dispersions, floccation, wetting phenomenae, and (bio-)lubrication. Of particular interest are two polymer brushes compressed against each other (so-called "polymer-brush bilayers"), which play an important role as model systems, e.g. to study biolubrication. Starting from the classical concepts to calculate the interaction free energy of such bilayers, known as the famous theory of Milner, Witten, and Cates and the scaling approach of Alexander and de Gennes, an alternative picture is developed that describes both numerical and experimental data significantly better. To this extent, basic scaling theory and the strong-stretching limit of the self-consistent mean-field theory will be discussed.