Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 45: Solid / liquid interfaces I
O 45.8: Talk
Wednesday, March 28, 2012, 12:15–12:30, A 060
Adsorption of P123 at the solid-liquid Interface — •Stefan Gerth1, Michael Klimczak1, Andrew Nelson2, Hans-Georg Steinrück1, and Andreas Magerl1 — 1Chair of Crystallography and Structural Physics, Staudtstraße 3, Erlangen — 2The Australian Nuclear Science and Technology Organization, Australia
Aqueous solutions of tri-block copolymers offer an excellent model system for the study of crystallization in soft matter. Further, these surfactants are well-known for the reduction of surface tension and to reduce friction at the interface. We investigate, as sample, the tri-block copolymer Pluronic P123 consisting of a central part of 70 propylene oxide (PO) units terminated by two end groups of 20 ethylene oxide (EO) units (EO20–PO70–EO20).
Our interest is in the near surface crystallization of a diluted Pluronic P123 system, below the temperature and concentration for crystallization in the bulk. In particular we are interested in the effect of shear for these agglomerated polymers.
The recovery of an adsorbed micellar layer was observed in dependence of the previously applied shear rate and polymer concentration. It has to be stressed that in this concentration and temperature regime no bulk crystallization occurs as investigated in small angle X-ray scattering measurements and rheometry data. Therefore, the ordering is only induced from the interface.