c-director relaxation around a vortex of strength +1 in free-standing smectic-C films
Institut für Experimentelle Physik, Otto-von-Guericke-Universität, Universitätsplatz 2, D-39106, Magdeburg, Germany
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Accepted: 2 October 2006
Published online: 9 November 2006
The relaxation of director fields in freely suspended smectic films is studied experimentally by means of polarizing microscopy, and analyzed by solving the torque balance equation under appropriate initial and boundary conditions. We consider in particular the role of anchoring conditions of the c-director at particles and defects in the film. The structure of regular relaxation patterns allows to determine the elastic anisotropy of smectic materials. The splay elastic constant can exceed the bend constant by a factor of two and more. A remarkable consequence of this anisotropy is the stick-slip-like relaxation around a central defect of topological strength s = + 1.
PACS: 61.30.Jf Defects in liquid crystals – / 05.45.-a Nonlinear dynamics and chaos – / 62.20.Dc Elasticity, elastic constants –
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2006