Surface anchoring on layers of grafted liquid-crystalline chain molecules: A computer simulation

By Monte Carlo simulations of a soft ellipsoid model for liquid crystals, we study whether a layer of grafted liquid-crystalline chain molecules can induce tilt in a nematic fluid. The chains are fairly short (four monomers) and made of the same particles as the solvent. They are attached to a substrate which favors parallel (planar) alignment. At low grafting densities, the substrate dominates and we observe planar alignment. On increasing the grafting density, we find a first order transition from planar to tilted alignment. Beyond the transition, the tilt angle with respect to the surface normal decreases continuously. The range of accessible anchoring angles is quite large.Comment: To appear in J. Chem. Phy

Discotic Mesophases of the Hexakis(alkylsulfono)benzene Series: Characterization by Differential Scanning Calorimetry, Optical Microscopy and Nuclear Magnetic Resonance Spectroscopy

Members of the Hexakis(alkylsulfono)benzene series 4, containing 7 to 15 carbon atoms per alkyl chain (4 c-k), exhibit one and possibly several liquid crystalline discotic mesophases. The mesophases are uniaxial and most probably have a columnar structure. Their anisotropic magnetic susceptibility is negative and in sufficiently strong magnetic fields they align with the director perpendicular to the field direction. Deuterium NMR spectra of C6D6 dissolved in the mesophases exhibit quadrupolar splittings which are strongly temperature dependent. In analogy with the conventional discotics this suggests the presence of multiple solvation sites for solute molecules

Nematische fluessige Kristalle fuer die Anwendung in Automobil-Displays Schlussbericht

With 11 figs., 10 tabs.SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman