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Structure formation control of disc-shaped molecules

: Janietz, D.


Molecular Crystals and Liquid Crystals 396 (2003), pp.251-264
ISSN: 0026-8941
ISSN: 1542-1406
Journal Article
Fraunhofer IAP ()

Supramolecular assemblies of radial multialkynylbenzene derivatives are presented which arise either from specific interactions with interfaces or from the covalent linkage of different molecular fragments. Surface-assisted molecular orientation control was investigated at the air/water interface, on photo-oriented azobenzene films and on rubbed polyimide orientation layers, respectively. Surface alignment generates edge-on or tilted orientations of the aromatic discs. Two- and three-dimensional architectures are formed which differ remarkably from the nematic-discotic bulk phases of the compounds. On the other hand, linking chemically a pentaalkynylbenzene donor moiety with an intramolecular acceptor function leads to charge-transfer mesogens, displaying novel types of mesophases which cannot be achieved with binary mixtures of flat donor and acceptor components.