Arthur Boller

Synthesis and some Physical Properties of Phenylpyrimidines

Abstract The four classes of 2,5-disubstituted cyano-alkylphenyl- and alkyl-cyanophenyl-pyrimidines have been prepared.

Low electrooptic threshold in new liquid crystals

New room temperature nematic liquid crystals with positive dielectric anisotropy were investigated in display cells with twisted nematic molecular ordering. Threshold voltages as low as 0.9 V and contrast ratios of 100:1 at 1.3 V are reported.

New Nematic Liquid Crystals: Influence of Rigid Cored, Alkenyl Side-Chains and Polarity on Material and Display Properties

Abstract From the design of non-polar molecular structures exhibiting different rigid cores and isolated C=C double bonds in different side-chain positions and from investigations into the static dielectric birefringence, viscous, and all three elastic constants k 1, k 2, k 3, new, negative dielectric anisotropic nenatic liqueid crystals result, namely apolar alkenyls, which are shown to cover a wide range of materail porpertie, including large twist constants k 2. The combination of double bonds in 4-position, with rigid cores comprising heterocyclic rings is shown to lead to exceptionally low elastic rations k 3/k 1 ∼ 0.4 with simultaeoulsy low optical anisotropies and low roatational viscosities γ1. Moreover, laterally substituted alkenyls are shown to exhibit large negative dielectric anisotropies rendering them applicable for low viscous, positive contrasat guest-host mixtures with high order parameters 0.72≤ S ≤ 0.78. The stability of the new nematics comprising isolated double bonds is shown to be ...