Comparative structural study of thin films of a columnar liquid crystal aligned by mechanical shearing and zone casting

Zone casting is a promising method for fabrication of open highly oriented crystalline and liquid crystalline (LC) films for various applications in (opto)electronics. We have performed a comparative structural analysis of mechanically sheared and zone-cast films of a model columnar LC. Grazing Incidence X-ray diffraction and UV–vis spectroscopy show that, contrary to the mechanically sheared films, the columns in the zone-cast films are aligned perpendicular to the casting direction. In the films, two LC domains with [20] or [11] reciprocal space vectors perpendicular to the substrate plane are observed. This can be explained by a small lattice mismatch allowing epitaxial growth of the LC domains on each other.