[DSC and temperature-dependent infrared spectroscopic study of hydrogen-bonded liquid crystal complexes].
The hydrogen-bonded liquid crystalline complexes based on 4', 4-bipyridine and 4-(trans-4-propylcyclohexyl) benzoic acid and trans-4-(trans-4-propylcyclohexyl)cyclohexyl carboxylic acid assigned as PCBA-BPy and PCCA-BPy were prepared and measured by polarized optical microscopy (POM), differential scanning calorimeter (DSC) and temperature-dependent FTIR It was found that PCBA-BPy and PCCA-BPy exhibited both smectic and nematic phase while all of their predecessors showed no smectic phase. The temperature-dependent FTIR studies revealed that the hydrogen bonding in complex PCBA-BPy was very different from that in PCCA-BPy. The wave number of C=O band had an obvious change at the crystal 1-crystal 2 transition but almost didn't change at smectic-nematic and nematic-isotropic transition; while in PCCA-BPy, it showed no sudden changes but shift to 1 709 cm(-1) gradually with the increase in temperature. The results from temperature-dependent FTIR studies also revealed that when the temperature was higher than the clearing point of the complexes, both of the complexes decomposed partially.
School of Materials Science and Engineering, University of Science and Technology, Beijing 100083, China.
Qiang
Q
Wei
Hui
H
Cao
Li-Pei
LP
Zhang
Xiao-Tao
XT
Yuan
Huai
H
Yang
Yan-Bin
YB
Wang