EPR study of the polydomain structure of the twist-bend nematic phase of CB9CB in the bulk
EPR study of the polydomain structure of the twist-bend nematic phase of CB9CB in the bulk
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DOI：
10.1080/02678292.2018.1501110
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发表时间：
2018-12-08
期刊：
影响因子：
2.2
通讯作者：
Zannoni，Claudio
中科院分区：
文献类型：
--
作者：
Bacchiocchi，Corrado;Tamba，Maria-Gabriela;Zannoni，Claudio
1“，9”-双（4-氰基联苯-4 '-基）壬烷（CB 9 CB）的X-型二聚体在本体中显示的液晶相的EPR自旋探针光谱表明，在从各向同性相冷却时，该材料形成具有沿光谱仪场沿着宏观取向的均匀指向矢的单轴X-型相。在进一步冷却时，在约4K的双相区之后观察到向扭曲弯曲的双相的转变。在这个较低温度的结晶阶段，指向矢看起来并不宏观地对准。的非均匀的董事分布建模为收集的单畴倾斜的磁场和周围的倾斜方向的取向分布。
EPR spin probe spectra of the liquid crystal phases exhibited, in the bulk, by the 1″,9″-bis(4-cyanobiphenyl-4’-yl)nonane (CB9CB) bent-shape dimer showed that, on cooling from the isotropic phase, this material forms a uniaxial nematic phase with a uniform director macroscopically aligned along the spectrometer field. Upon further cooling, a transition into the twist-bend nematic phase is observed after a biphasic region of approximately 4 K. In this lower temperature nematic phase, the director does not appear to be macroscopically aligned. The non-uniform director distribution is modelled as a collection of monodomains tilted with respect to the magnetic field and orientationally distributed around the tilt direction.