Premium
Effects of Alkyl Chain Length on Properties of 1‐Alkyl‐3‐methylimidazolium Fluorohydrogenate Ionic Liquid Crystals
Author(s) -
Xu Fei,
Matsumoto Kazuhiko,
Hagiwara Rika
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201001364
Subject(s) - alkyl , mesophase , crystallography , liquid crystal , ionic liquid , materials science , bilayer , texture (cosmology) , chemistry , ionic conductivity , organic chemistry , biochemistry , optoelectronics , electrode , artificial intelligence , membrane , computer science , electrolyte , image (mathematics) , catalysis
A series of 1‐alkyl‐3‐methylimidazolium fluorohydrogenate salts (C x MIm(FH) 2 F, x =8, 10, 12, 14, 16, and 18) have been characterized by thermal analysis, polarized optical microscopy, IR spectroscopy, X‐ray diffraction, and anisotropic ionic conductivity measurements. Liquid crystalline mesophases with a smectic A interdigitated bilayer structure are observed from C 10 to C 18 , showing a fan‐like or focal conic texture. The temperature range of the mesophase increases with the increase in the alkyl chain length (from 10.1 °C for C 10 MIm(FH) 2 F to 123.1 °C for C 18 MIm(FH) 2 F). The distance between the two layers in the smectic structure gradually increases with increasing alkyl chain length and decreases with increasing temperature. Conductivity parallel to the smectic layers is around 10 mS cm −1 regardless of the alkyl chain length, whereas that perpendicular to the smectic layers decreases with increasing alkyl chain length because of the thicker insulating sheet with the longer alkyl chain.