Abstract
Director fields around spherical and cylindrical micro particles embedded in a uniformly aligned nematic liquid crystal are investigated by means of fluorescence confocal polarizing microscopy. Both dipolar configurations (point-like defects) and quadrupolar configurations (ring-like defect lines) are observed for spherical particles. However, only defect lines appear in the vicinity of particles with cylindrical shape. In contrast to previous predictions for sphero-cylinders, the defect lines around the cylindrical particles studied here seem to be pinned at the cylinder edges. The experimental results are in good agreement with numerical simulations.
Acknowledgments
Financial support of this work by the European Science Foundation (EUROCORES, 05-SONS-FP-014) and the German Research Foundation (DFG, KI 411/14-1) is gratefully acknowledged.