Dynamics of electric-field-induced molecular reorientation of a surface-stabilized antiferroelectric liquid crystal in the smectic-C* phase probed by time-resolved infrared spectroscopy.
Dynamics of electric-field-induced molecular reorientation of a surface-stabilized antiferroelectric liquid crystal in the smectic-C* phase probed by time-resolved infrared spectroscopy.
复制标题
通过时间分辨红外光谱探测近晶 C* 相中表面稳定反铁电液晶的电场诱导分子重新取向的动力学。
DOI：
10.1103/physreve.63.051704
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Y. Ozaki
中科院分区：
文献类型：
--
作者：
A. Verma;B. Zhao;A. Bhattacharjee;Y. Ozaki
本文用偏振相关和时间分辨傅里叶变换红外光谱研究了手性反铁电液晶在不同温度下的电场诱导铁电相（Sm-C*）。在直流电场下的偏振相关的红外光谱表明，平均烷基链轴不重合的液晶基元轴，是相对于层正常比液晶基元倾斜。通过对不同时间延迟下红外吸收峰的时间响应分析，发现几乎所有的分子链段都围绕分子长轴发生了取向偏移和旋转受阻，整个分子的旋转也受到了阻碍。进一步推断，液晶基元，手性段，和烷基链达到其平衡取向在几乎相同的时间切换的交流电场的极性，但不同的分子片段通过不同的角度重新取向。
Polarization dependent and time-resolved Fourier transform infrared studies have been carried out on the electric-field-induced ferroelectric phase (Sm-C*) of a chiral, antiferroelectric liquid crystal at different temperatures. Polarization dependent infrared spectra under dc electric field reveal that the average alkyl chain axis does not coincide with the mesogen axis and is less tilted with respect to the layer normal than the mesogen. The analysis of the various absorbance profiles obtained from temporal response of absorption changes of infrared bands at different time delays provides clear evidence for biased orientation and hindered rotation of almost all the molecular segments around the average molecular long axis and the rotation of the whole molecule around its axis is also hindered. It is further inferred that the mesogen, the chiral segment, and the alkyl chains reach their equilibrium orientations at nearly the same time on switching the polarity of the ac electric field but the different molecular segments reorient through different angles.