Alignment of liquid crystals with patterned isotropic surfaces

The molecules of a nematic liquid crystal exposed to an isotropic surface a dopt a mean tilt relative to the normal but have no in-plane alignment-that is, they are free to have any azimuthal orientation in the surface plane. Pursuing the theoretical suggestion by Meyer that, in spite of this azimuth al degeneracy, spatially inhomogeneous isotropic surfaces combine with liqu id crystal elastic anisotropy to produce alignment, we show that a boundary line between two isotropic regions that differ in mean tilt does indeed al ign the liquid crystal. The boundaries on a patterned surface of distinct i sotropic regions thus act as a system of lines that the molecular orientati on locally follows. This enables the development of liquid crystal alignmen t surfaces based on printing or lithographic patterning.