EPR study of the polydomain structure of the twist-bend nematic phase of CB9CB in the bulk

被引:4
作者
Bacchiocchi, Corrado [1 ]
Tamba, Maria-Gabriela [2 ]
Mehl, Georg H. [2 ]
Arcioni, Alberto [3 ]
Miglioli, Isabella [3 ]
Zannoni, Claudio [3 ]
机构
[1] Univ Camerino, Div Chem, Sch Sci & Technol, Camerino, MC, Italy
[2] Univ Hull, Dept Chem, Kingston Upon Hull, N Humberside, England
[3] Univ Bologna, Dipartimento Chim Ind Toso Montanari, Bologna, Italy
基金
英国工程与自然科学研究理事会;
关键词
Bent-shaped bimesogenic liquid-crystals; dimers; orientational order; dynamics; LIQUID-CRYSTAL DIMERS; DIRECTOR CONFIGURATION; ORDER; DYNAMICS;
D O I
10.1080/02678292.2018.1501110
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
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. [GRAPHICS] .
引用
收藏
页码:2109 / 2120
页数:12
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