Supramolecule command surface for liquid crystal alignment

Devices based on liquid crystal display technology, ranging from watches to flat panel displays, have proliferated over the past few decades and can now be found in all conceivable aspects of everyday life. It is surprising that a crucial part in the construction of such displays, namely the alignment layer, which dictates the surface alignment of mesogenic molecules, relies essentially on a mechanical rubbing process which was invented 100 years ago. In this paper, recent developments in the construction of alignment layers (also called command layers) based on the self-assembly of molecular and macromolecular components are discussed. Two topics are highlighted: (i) tuneable layers formed by hierarchical assembly of siloxane oligomers and phthalocyanine dyes on indium-tin-oxide surfaces and (ii) command layers formed by self-assembly of porphyrin trimers. (c) 2007 Society of Chemical Industry