Dresden 2009 – scientific programme
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SYSO: Symposium Self-organizing Surfaces and Interfaces
SYSO 7: Self-Organizing Surfaces and Interfaces VI
SYSO 7.5: Talk
Thursday, March 26, 2009, 16:45–17:00, GÖR 226
Structure Formation Kinetics in Evaporating Droplets of Diblock-Copolymer Solutions — •Silke Rathgeber1,2, Diogo Bastos de Toledo1, Andreas Timmann3, and Stephan Roth3 — 1Max Planck-Institute for Polymer Research, 55128 Mainz, Germany. — 2Johannes Gutenberg-University, 55099 Mainz, Germany. — 3HASYLAB at DESY, 22603 Hamburg, Germany.
We followed the structure formation kinetics in droplets of diblock-copolymer solutions during the evaporation process using grazing incidence small-angle x-ray scattering. Aim of our investigation was to get insight which impact the confining interfaces, film-air and film-substrate, have on the structure formation in the droplets during the later stages of the evaporation process. As model system we have chosen poly(styrene)-b-poly(isoprene) (PS-PI) diblock-copolymers solved in anisole, a low-vapor-pressure solvent with sufficient slow evaporation rate. We investigated symmetric as well as asymmetric PS-PI diblock copolymers which form lamellar and hexagonal bulk phases. The particular setup of our experiment allowed us to follow the structural changes occuring at the film-air interface as well as close to the substrate-film interface simultanously. Ordering starts at the substrate. Skin layer formation at the film-air interface is not observed. The talk will discuss the drying scenarios in detail. This includes the appearence of interface mediated structures.