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DY: Fachverband Dynamik und Statistische Physik

DY 16: Pattern Formation

DY 16.5: Vortrag

Mittwoch, 13. März 2013, 11:00–11:15, H46

Orientational selection in pattern formation — •Vanessa Weith, Alexei Krekhov, and Walter Zimmermann — Universität Bayreuth, Theoretische Physik I, 95440 Bayreuth, Germany

Spatially periodic patterns in two-dimensional isotropic systems are on large length scales orientationally disordered. Examples are lamellae in diblock copolymers with the lamellae perpendicular to substrates or stripe patterns occurring in experiments on gas convection in large aspect ratio systems.

The orientational selection of the wave vector q of lamellae in diblock copolymers or stripe patterns in model systems can be induced by appropriate surface preparations of confining substrates. In addition we show, that the orientation of q of lamellae and stripe patterns can be controlled by traveling, spatially periodic modulations of the control parameter. Assuming a parallel orientation of the wave vector k and the velocity v of the modulation, we find in the case of a small velocity that the wave vector of patterns, q, orients perpendicular to v and parallel to v in the case of larges values of |v |.