Publication Title

Physical Review E

Publication Date

9-15-2002

Document Type

Article

DOI

10.1103/PhysRevE.66.031708

Keywords

Achiral Molecules, Behavior, Phases

Disciplines

Physics

Abstract

Electro-optical, calorimetric, x-ray, and dielectric measurements are reported on a mixture containing a bent-core liquid crystal 4-chloro-1,3-phenylinebis [4-(4-n-tetradecyloxyphenyliminomethyl) benzoate] mixed with the nonpolar solvent n-hexadecane (HEX). It is observed that the addition of HEX depresses the isotropic-to-smectic phase transition temperature, but the crystallization temperature does not change considerably. Instead, the texture of the crystalline phase changes and, at sufficiently high concentrations of HEX (>20 wt %), an optically isotropic phase appears. Above 40 wt % HEX concentrations, the mesophase completely disappears and a direct isotropic solid-to-isotropic liquid transition takes place. At increasing HEX concentration, the transition enthalpies, the layer ordering, and the magnitude of the electric polarization decrease. X-ray studies reveal that HEX molecules pack in between the smectic layers, resulting in an increase of the layer spacing by about 3 Angstrom. The increase of the layer spacing saturates at 5 wt % of HEX. The phase segregation observed seems to be due to steric interactions between the flexible HEX molecules and the rigid bent cores of the liquid crystal molecules.

Comments

Copyright 2002 American Physical Society. Available on publisher's site at http://dx.doi.org/10.1103/PhysRevE.66.031708


Included in

Physics Commons

Share

COinS