Dielectric, calorimetric and mesophase properties of 1′′-(2′,4-difluorobiphenyl-4′-yloxy)-9′′-(4-cyanobiphenyl-4′-yloxy) nonane: an odd liquid crystal dimer with a monotropic mesophase having the characteristics of a twist-bend nematic phase
作者:N. Sebastián、D. O. López、B. Robles-Hernández、M. R. de la Fuente、J. Salud、M. A. Pérez-Jubindo、D. A. Dunmur、G. R. Luckhurst、D. J. B. Jackson
DOI:10.1039/c4cp03462g
日期:——
about the molecular dynamics in the isotropic phase, in the nematic mesophase and across the isotropic-to-nematic phase transition. Two orientations, parallel and perpendicular to the director, have been investigated. In the high temperature nematic mesophase, the dielectric anisotropy is found to be positive. Measurements of the parallel component of the dielectric permittivity are well-explained by the
本文报道了一种新型的液晶相,该液晶相具有由非对称醚键连接的液晶二聚体形成的扭曲弯曲向列相的特征。二聚体1'-((2',4-二氟联苯-4'-基氧基)-9''-(4-氰基联苯-4'-基氧基)壬烷(FFO9OCB)在充分高的冷却下显示出两个液晶相各向同性相的速度 高温中间相在文献中已被报道为向列型,并在本研究中得到证实。另一个中间相是亚稳态的,可以过冷,从而产生玻璃态。它的鉴定和表征是基于光学纹理,宽带介电谱,量热法,向列相中张量和弯曲弹性常数的测量以及可混溶性研究。结论是,低温中间相表现出扭曲弯曲向列相的特征。介电测量使我们能够获得静态介电常数和各向同性相,向列介观相以及各向同性至向列相变中分子动力学的信息。已经研究了平行于和垂直于指向矢的两个方向。在高温向列中间相中,发现介电各向异性为正。介电常数的平行分量的测量由向列二聚体中的介电弛豫的分子理论很好地解释了(M. Stocchero,A。Ferrarini,GJ