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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 35: Microfluidics II: Boundary conditions
CPP 35.4: Vortrag
Donnerstag, 26. März 2009, 15:00–15:15, ZEU 160
In-situ investigation of the solid/liquid interface of a block copolymer solution under shear stress with µ-focus GISAXS — •Andreas Timmann1, Stephan Volkher Roth1, Steffen Fischer2, and Stephan Förster2 — 1HASYLAB at DESY, Notkestr. 85, D-22603 Hamburg, Germany — 2Inst. f. Phys. Chem., Uni HH, Grindelallee 117, D-20145 Hamburg, Germany
Block-copolymers are interesting for their ability to self organize in various structures. In dilute solution they form micelles, cylindrical micelles and vesicles. The length scales of these structures ranges from about 5 nm up to several hundred nanometres. Hence such structures are well suited for investigations using small-angle X-ray scattering.
The experiments were performed the beamline BW4 at HASYLAB, Hamburg [1] using the microfocus set-up. We present the results of the investigation of a 13 wt.% solution of a poly-(isoprene-block-ethylene oxide) in water. The block degrees of polymerization of the isoprene and the polyethylene oxide were 55 and 170, respectively. The shear stress was applied by a stress-controlled Bohlin CVO rheometer in a plate-plate-geometry with a diameter of 20 mm and a gap of 1 mm. We investigated the interface layer of the solution with the rotor of the shear geometry at different temperatures. Under shear a desorption of the micelles from the rotor plate was observed, which is independent of the actual shear rate. [2]
References:
Roth et al., Rev. Sci. Instrum., 2006, 77, 085106
Timmann et al., App. Phys. Let., 2007, 91, 213102