Structure of smectic defect cores: an X-ray study of 8CB liquid crystal   ultra-thin films
  We study the structure of very thin liquid crystal films frustrated by antagonistic anchorings in the smectic phase. In a cylindrical geometry, the structure is dominated by the defects for film thicknesses smaller than 150 nm and the detailed topology of the defects cores can be revealed by x-ray diffraction. They appear to be split in half tube-shaped Rotating Grain Boundaries (RGB). We determine the RGB spatial extension and evaluate its energy per unit line. Both are significantly larger than the ones usually proposed in the literature 
Jean-Philippe Michel (INSP), Emmanuelle Lacaze (INSP), Michel Goldmann   (INSP), Marc Gailhanou (LURE), Marc De Boissieu (LT...