Columnar Liquid Crystals (columnar + liquid_crystal)

Distribution by Scientific Domains


Selected Abstracts


Electric-Field-Responsive Lithium-Ion Conductors of Propylenecarbonate-Based Columnar Liquid Crystals

ADVANCED MATERIALS, Issue 16 2009
Harutoki Shimura
One-dimensional lithium-ion conductors responsive to electric fields are prepared by the complexation of a columnar propylenecarbonate-based liquid crystal and lithium triflate. The assemblies are aligned macroscopically by an alternating electric field, and they transport ions along the columnar axes. [source]


Homeotropic Alignment of Columnar Liquid Crystals in Open Films by Means of Surface Nanopatterning,

ADVANCED MATERIALS, Issue 6 2007
I. Gearba
Columnar liquid crystals (LCs) are reported to align spontaneously homeotropically,that is, orthogonally to the surface (see figure and inside cover),on a glass surface covered with a layer of poly(tetrafluoroethylene) transferred by friction (rubbing). This strategy for producing macroscopic monodomains of homeotropically aligned LCs may find important applications in the fabrication of LC-based organic solar cells. [source]


UV/Vis to NIR Photoconduction in Cyclopalladated Complexes

CHEMISTRY - AN ASIAN JOURNAL, Issue 7 2009
Nicolas Godbert
Abstract Funky discotics: Photoconductivity is measured in newly synthesized cyclopalladated metallomesogens exhibiting hexagonal columnar mesophases at room temperature. The tuning of the HOMO/LUMO energy levels by modification of the chain/core linkage (ester 1 vs ether 2) makes compound 2 photoconductive across the whole UV/Vis/NIR range. The incorporation of a rigid core, formed by a cyclopalladated azobenzene fragment bonded to an ancillary Schiff base ligand, into molecules with 12 or 11 peripheral alkyl chains has been successfully achieved. These new complexes, 1 and 2, respectively, are columnar liquid crystals between room temperature and about 50,°C. Both cyclometallated and ancillary ligands have been polyalkylated through either aryl ester (electron-withdrawing group) or aryl ether (electron-releasing group) linkages, in order to tune the HOMO/LUMO energy levels. The photoconductive properties of 1 and 2 have been studied as a function of their absorption properties before and after annealing, from the UV/Vis to NIR region. Compared with the reference compounds, tris-alkynyl benzene discotics, these new materials gave similar performances (,/I,8×10,13,S,cm,W,1 with E=10,V,,m,1 at ,=370,nm). Moreover, complex 2 shows a normalized photoconductivity ,/I=8.5×10,13,S,cm,W,1 at ,=760,nm. Organic photoconductors in such a high wavelength spectral range are not common and are usually assembled by mixing dyes with organic semiconductors. [source]


Electroluminescent Diodes from Complementary Discotic Benzoperylenes

CHEMPHYSCHEM, Issue 9 2003
Sonia Alibert-Fouet Dr.
Unequal brothers: Benzoperylene carboxylic acid derivatives with flexible chains not only form charge-transporting columnar liquid crystals (see graphic), their charge-transport properties can also be tuned to be either of n - or of p -type: relatively minor changes in the substitution pattern yield different materials that are complementary enough to form red-fluorescent charge-transfer complexes and p,n junction electronic devices. [source]