Explanations of the cover picture
Nu: streak texture of a uniaxial nematic mesophase with typical four or two strips per defect.
Nb: biaxial nematic mesophase with only two strips per defect.
Colh: pseudo-focal conical texture of a 2-dimensional hexagonal columnar mesophase (p6mm). The texture is obtained between two crossed polarisers. The columns are spirally wound around the central defect and lies planar on the substrate surface. This creates a texture similar to a Maltese cross.
Colorh: texture of an ondulated mesophase with 3-dimensional, orthorhombic columnar structure. This mesophase is formed by cooling of the hexagonal phase. The helical superstructure of the columns and their resulting ondulated column morphology leads to a 3D positional range of the columns.
CubI: facet structure of a drop of a cubic-centered mesophase consisting of micelles, which are built up by conically folded star mesogens.
Conoscopic images of a uniaxial and biaxial nematic mesophase. A closed Isogyren cross, also with rotation of the sample, indicates a uniaxial phase. An open cross indicates a biaxial phase. An additional inserted circular polarizer makes the optical axis visible.