학술논문

Physical properties of a bent-core nematic liquid crystal and its mixtures with calamitic molecules.
Document Type
Article
Source
Phase Transitions. Oct2012, Vol. 85 Issue 10, p872-887. 16p. 1 Black and White Photograph, 4 Diagrams, 1 Chart, 4 Graphs.
Subject
*NEMATIC liquid crystals
*MIXTURES
*PHYSICS experiments
*PHENYLENE compounds
*BENZOATES
*BROADBAND dielectric spectroscopy
*ELASTIC constants
Language
ISSN
0141-1594
Abstract
This article summarizes the results obtained by various experimental methods on the physical properties of a bent-core nematic liquid crystal 4-chloro-1,3-phenylene bis-4-[4′-(9-decenyloxy) benzoyloxy] benzoate (ClPbis10BB). The material exhibits unusual properties in all aspects tested. Its bend flexoelectric coefficient is 1000 times larger than in calamitics; it is viscoelastic with a large, shear-rate-dependent viscosity. Its bend and twist elastic constants are abnormally low; thus the nematic phase can be rendered to be a blue fog phase with a small amount of chiral dopant. It shows very high flow birefringence and unusually small leading Landau coefficient. It has two types of isotropic phases; at lower temperature it is probably tetrahedratic that can be transferred into the nematic phase with magnetic field. ClPbis10BB has a frequency-dependent conductivity anisotropy which is characterized by a double sign inversion. It exhibits various electroconvection (EC) patterns which are currently not understood in the frame of the standard theory of EC. [ABSTRACT FROM PUBLISHER]