Reorientation behaviour of bent core molecules in response to an external electric field as detected by time-resolved FTIR spectroscopy
Reorientation behaviour of bent core molecules in response to an external electric field as detected by time-resolved FTIR spectroscopy
复制标题
时间分辨 FTIR 光谱检测到弯曲核心分子响应外部电场的重新取向行为
DOI：
10.1080/026782999204093
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发表时间：
1999
期刊：
影响因子：
2.2
通讯作者：
F. Kremer
中科院分区：
文献类型：
--
作者：
S. Shilov;S. Rauch;H. Skupin;G. Heppke;F. Kremer
采用时间分辨偏振傅里叶变换红外光谱（FTIR）分析了非手性弯曲核心分子在外加电场作用下的取向和迁移率。通过剪切ITO涂层CaF2窗口之间的物质，在高温B2相中形成了外消旋和同手性两种结构域。这些领域的每一个都具有两个自发的对称性破断不稳定性，分别产生对称和反对称的电光响应。利用红外光谱的特异性，在分子水平上分析了弯核液晶材料的这种开关行为。通过这种方法，可以详细地跟踪电诱导锥体上不同段的重定向和高频反铁电结构的抑制。此外，还确定了两个羰基围绕分子长轴的偏旋。结果表明……
Time-resolved polarized Fourier transform infrared spectroscopy (FTIR) is employed to analyse the segmental orientation and mobility of achiral bent core molecules in response to an external electric field. By shearing the substance between ITO coated CaF2 windows two types of domain, racemic and homochiral, are formed in the high temperature B2 phase. Each of these domains is characterized by two spontaneous symmetry-breaking instabilities which yield a symmetric and an antisymmetric electro-optical response, respectively. Taking advantage of the specificity of IR spectroscopy, this switching behaviour is analysed on a molecular level for the moieties of the bent core liquid crystal materials. In this way, the electrically induced reorientation of the different segments on a cone and the suppression of the antiferroelectric structure at higher frequencies can be followed in detail. Furthermore the biased rotation of the two carbonyl groups around the molecular long axis is determined. It is shown that al...